Condensed Matter
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 [1] arXiv:2406.12886 [pdf, other]

Title: Bessel beam fabrication of graphitic micro electrodes in diamond using laser burstsAkhil Kuriakose, Francesco P. Mezzapesa, Caterina Gaudiuso, Andrea Chiappini, Federico Picollo, Antonio Ancona, Ottavia JedrkiewiczSubjects: Materials Science (condmat.mtrlsci); Optics (physics.optics)
We present the fabrication of conductive graphitic microelectrodes in diamond by using pulsed Bessel beams in the burst mode laser writing regime. The graphitic wires are created in the bulk of a 500 {\mu}m thick monocrystalline HPHT diamond (with (100) orientation) perpendicular to the sample surface, without beam scanning or sample translation. In particular, the role of different burst features in the resistivity of such electrodes is investigated for two very different subpulse durations namely 200 fs and 10 ps, together with the role of thermal annealing. MicroRaman spectroscopy is implemented to investigate the laserinduced crystalline modification, and the results obtained by using two different laser repetition rates, namely 20 Hz and 200 kHz, are compared. A comparison of the microRaman spectra and of the resistivity of the electrodes fabricated respectively with 10 ps single pulses and with bursts (of subpulses) of similar total duration has also been made, and we show that the burst mode writing regime allows to fabricate more conductive micro electrodes, thanks to the heat accumulation process leading to stronger graphitization. Moreover, the microfabrication of diamond by means of the longest available bursts (~ 46.7 ps duration) featured by 32 subpulses of 200 fs duration, with intraburst time delay of 1.5 ps (subTHz bursts), leads to graphitic wires with the lowest resistivity values obtained in this work, especially at low repetition rate such as 20 Hz. Indeed, micro electrodes with resistivity on the order of 0.01 {\Omega} cm can be fabricated by Bessel beams in the burst mode regime even when the bursts are constituted by femtosecond laser subpulses, in contrast with the results of the standard writing regime with single fs pulses typically leading to less conductive micro electrodes.
 [2] arXiv:2406.12888 [pdf, html, other]

Title: A Space Group Symmetry Informed Network for O(3) Equivariant Crystal Tensor PredictionComments: This paper has been accepted to ICML 24 as a poster. You are encouraged to cite the conference version of this paperSubjects: Materials Science (condmat.mtrlsci); Artificial Intelligence (cs.AI); Atomic Physics (physics.atomph)
We consider the prediction of general tensor properties of crystalline materials, including dielectric, piezoelectric, and elastic tensors. A key challenge here is how to make the predictions satisfy the unique tensor equivariance to O(3) group and invariance to crystal space groups. To this end, we propose a General Materials Tensor Network (GMTNet), which is carefully designed to satisfy the required symmetries. To evaluate our method, we curate a dataset and establish evaluation metrics that are tailored to the intricacies of crystal tensor predictions. Experimental results show that our GMTNet not only achieves promising performance on crystal tensors of various orders but also generates predictions fully consistent with the intrinsic crystal symmetries. Our code is publicly available as part of the AIRS library (this https URL).
 [3] arXiv:2406.12889 [pdf, other]

Title: Widebandgap semiconductor of threedimensional unconventional stoichiometric NaCl2 crystalSiyan Gao, Junlin Jia, Xu Wang, YueYu Zhang, Yijie Xiang, Pei Li, Ruobing Yi, Xuchang Su, Guosheng Shi, Feifei Qin, YiFeng Zheng, Lei Chen, Yu Qiang, Junjie Zhang, Lei Zhang, Haiping FangSubjects: Materials Science (condmat.mtrlsci)
The expanding applications call for novel newgeneration widebandgap semiconductors. Here, we show that a compound only composed of the ordinary elements Na and Cl, namely threedimensional NaCl2 crystal, is a widebandgap semiconductor. This finding benefits from the breaking of conventional stoichiometry frameworks in the theoretical design, leading to the discovery of threedimensional XY2 (X = Na, Li, K; Y = Cl, F, Br, I) crystals, with covalent bonds of Y pairs inducing the wide bandgap from 2.24 to 4.45 eV. Crucially, such an unexpected NaCl2 crystal was successfully synthesized under ambient conditions. The unconventional stoichiometric strategy with other chemical elements potentially yields more widebandgap semiconductors, offering the capability for bandgap tuning. These unconventional stoichiometric materials may also exhibit superconductivity, transparent inorganic electrides, highenergydensity, and beyond.
 [4] arXiv:2406.12893 [pdf, html, other]

Title: A variational method for the simulation of hydrogen diffusion in metalsSubjects: Materials Science (condmat.mtrlsci); Computational Physics (physics.compph)
We present a new method for the approximate solution of the strongly coupled, nonlinear stressdiffusion problem that appears when modeling hydrogen transport in metals. The most salient feature of the proposed approximation is that it is fully variational, meaning that all the discrete equations are obtained from the optimality conditions of an incremental potential, even for inelastic mechanical behavior. Like other variational methods, the proposed algorithm has remarkable properties, including the symmetry of the tangent operator, making its solution extremely efficient compared to other similar methods available in the literature.
 [5] arXiv:2406.12894 [pdf, html, other]

Title: The importance of definitions in crystallographyComments: 10 pages, 10 figures. The latest version is maintained at this https URLJournalref: Published in IUCrJ, v.11 (4), 2024Subjects: Materials Science (condmat.mtrlsci)
This paper was motivated by the articles "Same or different  that is the question" in CrystEngComm (July 2020) and "Change to the definition of a crystal" in the IUCr newsletter (June 2021). Experimental approaches to crystal comparisons require rigorously defined classifications in crystallography and beyond. Since crystal structures are determined in a rigid form, their strongest equivalence in practice is rigid motion, which is a composition of translations and rotations in 3dimensional space. Conventional representations based on reduced cells and standardizations theoretically distinguish all periodic crystals. However, all cellbased representations are inherently discontinuous under almost any atomic displacement that can arbitrarily scale up a reduced cell. Hence comparing millions of known structures in materials databases needs continuous distance metrics.
 [6] arXiv:2406.12940 [pdf, html, other]

Title: Measurement of exciton fraction of microcavity excitonpolaritons using transfermatrix modelingJonathan Beaumariage, Zheng Sun, Hassan Alnatah, Qi Yao, David M. Myers, Mark Steger, Ken West, Kirk Baldwin, Loren N. Pfeiffer, Man Chun Alan Tam, Zbig R. Wailewski, David W. SnokeComments: 16 pages, 11 figuresSubjects: Mesoscale and Nanoscale Physics (condmat.meshall); Quantum Gases (condmat.quantgas)
We present a careful calibration of the exciton fraction of polaritons in high$Q$ ($\sim 300,000$), longlifetime ($\sim 300$ ps), GaAs/AlGaAs microcavities.This is a crucial parameter for manybody theories which include the polaritonpolariton this http URL is much harder to establish this number in high$Q$ structures compared to low$Q$ structures, because the upper polariton is nearly invisible in high$Q$ cavities.We present a combination of photoluminescence, photoluminescence excitation, and reflectivity measurements to highly constrain the fit model, and compare the results of this model to the results from low$Q$ structures.We present a fitted curve of exciton fraction as a function of the lower polariton energy for multiple samples which have been used in prior experiments.
 [7] arXiv:2406.12962 [pdf, html, other]

Title: Gauging modulated symmetries: KramersWannier dualities and noninvertible reflectionsComments: 67 pagesSubjects: Strongly Correlated Electrons (condmat.strel); High Energy Physics  Theory (hepth); Mathematical Physics (mathph); Quantum Physics (quantph)
Modulated symmetries are internal symmetries that act in a nonuniform, spatially modulated way and are generalizations of, for example, dipole symmetries. In this paper, we systematically study the gauging of finite Abelian modulated symmetries in ${1+1}$ dimensions. Working with local Hamiltonians of spin chains, we explore the dual symmetries after gauging and their potential new spatial modulations. We establish sufficient conditions for the existence of an isomorphism between the modulated symmetries and their dual, naturally implemented by lattice reflections. For instance, in systems of prime qudits, translation invariance guarantees this isomorphism. For nonprime qudits, we show using techniques from ring theory that this isomorphism can also exist, although it is not guaranteed by lattice translation symmetry alone. From this isomorphism, we identify new KramersWannier dualities and construct related noninvertible reflection symmetry operators using sequential quantum circuits. Notably, this noninvertible reflection symmetry exists even when the system lacks ordinary reflection symmetry. Throughout the paper, we illustrate these results using various simple toy models.
 [8] arXiv:2406.12963 [pdf, html, other]

Title: Weak Superfluidity in Twisted Optical PotentialsComments: 11 pages, 5 figures, comments welcomeSubjects: Quantum Gases (condmat.quantgas); Disordered Systems and Neural Networks (condmat.disnn); Strongly Correlated Electrons (condmat.strel)
A controlled twist between different underlying lattices allows one to interpolate, under a unified framework, across ordered and (quasi)disordered matter while drastically changing quantum transport properties. Here, we use quantum Monte Carlo simulations to determine the unique phase diagrams of stronglycorrelated ultracold bosons in twisted optical potentials. We show that at commensurate twisting angles, spectral gaps govern the formation of insulating patterns, separated by thin superfluid domains. The latter form weak superfluids, which are very sensitive to thermal fluctuations, but can be stabilized under appropriate parameter control. In contrast, slightly changing the twisting angle to a incommensurate value destroys most spectral gaps, leaving behind a prominent Bose glass phase. Our results are directly applicable to current generation experiments that quantum simulate moiré physics.
 [9] arXiv:2406.12964 [pdf, html, other]

Title: Vortex structure in a $d$wave superconductor obtained by a confinement transition from the pseudogap metalComments: 30 pages, 10 figuresSubjects: Strongly Correlated Electrons (condmat.strel); Superconductivity (condmat.suprcon)
We compute the structure of flux $h/(2e)$ vortices in a $d$wave superconductor using a continuum SU(2) gauge theory of 2 flavors of charge $e$, SU(2)fundamental Higgs bosons. Period2 charge order is present near the vortex center. Upon coupling the electrons to the superconducting and charge order parameters, we find that the electronic local density of states does not have a zerobias peak, in contrast to BCS theory. But there are subgap peaks at positive and negative bias, and these exhibit antiphase periodic spatial modulations, as observed in scanning tunneling microscopy experiments in the underdoped cuprates (K. Matsuba et al., J. Phys. Soc. Jpn. 76, 063704 (2007)).
 [10] arXiv:2406.12965 [pdf, html, other]

Title: Spin mechanism of drag resistance in stronglycorrelated electron liquidsComments: 10 pages, 3 figuresSubjects: Strongly Correlated Electrons (condmat.strel)
We investigate the effect of Coulomb drag resistance in a bilayer system of stronglycorrelated electron liquids magnetized by an inplane field employing the framework of hydrodynamic theory. We identify a mechanism for drag magnetoresistance, which physically arises from the spin diffusion driven by fluctuations of the spin currents within a partially spinpolarized fluid. This effect is further enhanced by acoustic and optic plasmon resonances within the bilayer, where hydrodynamic plasmons are driven by fluctuating viscous stresses. We express the drag magnetoresistivity in terms of the intrinsic dissipative coefficients and basic thermodynamic properties of the electron fluid. Our results are derived nonperturbatively in interaction strength and do not rely on assuming Fermiliquid behavior of the electron liquid, and applicable also in the regimes of semiquantum and highly correlated classical fluids.
 [11] arXiv:2406.12966 [pdf, html, other]

Title: Origin of the hidden energy scale and the $f$ratio in geometrically frustrated magnetsComments: 4.5+1 pages, 3+2 figures, 2 tablesSubjects: Strongly Correlated Electrons (condmat.strel); Mesoscale and Nanoscale Physics (condmat.meshall); Materials Science (condmat.mtrlsci); Quantum Gases (condmat.quantgas); Statistical Mechanics (condmat.statmech)
Sufficiently clean geometrically frustrated (GF) magnets are the largest class of candidate materials that may host quantum spin liquids (QSLs). Some of them have been shown to exhibit spinglass freezing, potentially precluding QSLs, at the "hidden energy scale", which is significantly lower than the microscopic energy scale of spin interactions. Here, we investigate the origin of the hidden energy scale and its relationship to the $f$ratio, the figure of merit for the degree of frustration in GF magnetic materials. The available experimental and numerical data provide evidence that GF magnets display, universally, two distinct temperature scales in the specific heat, the lowest of which is of the order of the hidden energy scale $T^*$. We argue that this scale is determined by nonmagnetic excitations, similar to spin exchanges in chains of spins. The collective entropy of such excitations matches the entropy of the ground states of the Ising model on the same lattice, which provides a way to verify the proposed scenario in experiment. We further confirm this scenario of the hidden energy scale by numerical simulations of spins on the kagome lattice. As $T^*$ is a property of the clean GF medium, it leads to a constraint on the $f$ratio.
 [12] arXiv:2406.12967 [pdf, html, other]

Title: Fluctuation Spectrum of Critical Fermi SurfacesComments: 52 pages, 7 figures; Part of the manuscript first appeared in arXiv:2311.03455 and arXiv:2311.03458. The current manuscript combines and expands the two previous manuscripts in a selfcontained style with additional resultsSubjects: Strongly Correlated Electrons (condmat.strel); High Energy Physics  Theory (hepth)
We investigate the Gaussian fluctuation spectrum of the large $N$ YukawaSYK model, which describes a Fermi surface coupled to an Isingnematic quantum critical point in (2+1) spacetime dimensions with translation symmetry. The large $N$ saddle point is described by the MigdalEliashberg equations, and the Gaussian fluctuation around it is generated by the BetheSalpeter kernel $K_\text{BS}$. Based on the Ward identities, we propose an inner product on the space of two point functions, which reveals a large number of soft modes of $K_\text{BS}$. These soft modes parameterize deformation of the Fermi surface, and their fluctuation eigenvalues describe their decay rates. We analytically compute these eigenvalues for a circular Fermi surface, and we discover the oddparity modes to be parametrically longerlived than the evenparity modes, due to the kinematic constraint of fermions scattering on a convex FS. The sign of the eigenvalues signals an instability of the Isingnematic quantum critical point at zero temperature for a convex Fermi surface. At finite temperature, the system can be stabilized by thermal fluctuations of the critical boson. We derive an effective action that describes the softmode dynamics, and it leads to a linearized Boltzmann equation, where the real part of the softmode eigenvalues can be interpreted as the collision rates. The structure of the effective action is similar to the theory of linear bosonization of a Fermi surface. Analyzing the Boltzmann equation, we obtain a conventional hydrodynamic transport regime and a tomographic transport regime. In both regimes, the conductance of the system in finite geometry can be a sharp indicator for the softmode dynamics and nonFermi liquid physics.
 [13] arXiv:2406.12968 [pdf, html, other]

Title: Unconventional earlytime relaxation in the Rydberg chainSubjects: Statistical Mechanics (condmat.statmech); Strongly Correlated Electrons (condmat.strel)
We show that unconventional relaxation dynamics of special initial states in onedimensional arrays of Rydberg atoms produce nongeneric decay of the initialstate survival probability at early times. Using the PXP hamiltonian as a minimal model of the Rydberg blockade, we prove that the earlytime survival probability for states exhibiting quantum manybody scarring decays at a characteristic rate, whose finitesize scaling is determined solely by scars. We numerically investigate the effects of both revivalenhancing and ergodicityrestoring perturbations and find results consistent with the limiting cases of integrable and ergodic dynamics, respectively. Since the survival probability is easily accessible experimentally at early times, our findings enable us to probe the presence of scars at time scales much shorter than that of thermalization.
 [14] arXiv:2406.12971 [pdf, html, other]

Title: SuperconductorInsulator Transition in the TMD moir\'{e} systems and the Deconfined Quantum Critical PointComments: 10 pages, 6 figuresSubjects: Strongly Correlated Electrons (condmat.strel)
We propose that the recently observed superconductorinsulator transition (SIT) in the twisted bilayer transition metal dichalcogenides moiré system at hole filling $\nu = 1$ may be described by the deconfined quantum critical point (DQCP), which was originally proposed for the transition between the Néel order and the valence bond solid (VBS) order on the square lattice. The key symmetries involved in the original DQCP include a $\mathrm{SO}(3)_s$ spin symmetry, as well as a $C_4$ lattice rotation symmetry for the VBS order that is enlarged into a $\mathrm{U}(1)_v$ symmetry near the DQCP. In the current SIT under consideration, the counterpart of the $\mathrm{SO}(3)_s$ spin symmetry is an approximate $\mathrm{SO}(3)_v$ symmetry that transforms between different crystalline orders on the triangular lattice; and the role of the $\mathrm{U}(1)_v$ symmetry is replaced by the ordinary charge$\mathrm{U}(1)_e$ symmetry. And at the DQCP the $\mathrm{SO}(3)_v \times \mathrm{U}(1)_e$ may enlarge into an emergent $\mathrm{SO}(5)$ symmetry. Under strain, the SIT is driven into either a prominent first order transition, or an "easyplane" DQCP, which is expected to have an emergent $\mathrm{O}(4)$ symmetry.
 [15] arXiv:2406.12972 [pdf, html, other]

Title: A fractal geometry immersed in a hierarchical magnetic flux distributionComments: 5 page, 6 figures; Sierpinski gasket (SPG) fractal geometry; Comments are welcomeSubjects: Mesoscale and Nanoscale Physics (condmat.meshall); Disordered Systems and Neural Networks (condmat.disnn); Statistical Mechanics (condmat.statmech)
Fractal geometry presents us with a selfsimilarity in their pattern at various length scales that is prevalent in our natural world. We present theoretical model of a Sierpinski gasket (SPG) fractal geometry with a deterministic perturbation in the form of a hierarchical distribution of magnetic flux. Such flux configuration induces a deterministic disorder in the AharonovBohm (AB) phases picked up by the electron wavefunction. Using the tightbinding formalism, we show that by tunning the strength of the hierarchy parameter of those AB phases, one can systematically engineer quantum states in a SPG fractal lattice. In addition to this, we have also observed that by controlling the strength of this hierarchy parameter in the magnetic flux, one can effectively regulate the persistent current in the SPG fractal structure. This characteristic is found to be true for various filling factors. Our results could be useful for designing nanoelectronic devices using molecular fractal structures fabricated by chemical synthesis technique.
 [16] arXiv:2406.12981 [pdf, html, other]

Title: Quantum geometry of bosonic Bogoliubov quasiparticlesComments: 7+21 pages, 4 figuresSubjects: Quantum Gases (condmat.quantgas); Mesoscale and Nanoscale Physics (condmat.meshall); Quantum Physics (quantph)
Topological and geometrical features arising in bosonic Bogoliubovde Gennes (BdG) systems have mainly been studied by utilizing a generalized symplectic version of the Berry curvature and related Chern numbers. Here, we propose a symplectic quantum geometric tensor (SQGT), whose imaginary part leads to the previously studied symplectic Berry curvature, while the real part gives rise to a symplectic quantum metric, providing a natural distance measure in the space of bosonic Bogoliubov modes. We propose how to measure all components of the SQGT by extracting excitation rates in response to periodic modulations of the systems' parameters. Moreover, we connect the symplectic Berry curvature to a generalized symplectic anomalous velocity term for Bogoliubov Bloch wave packets. We test our results for a bosonic BogoliubovHaldane model.
 [17] arXiv:2406.13044 [pdf, html, other]

Title: The Origin of Photoplasticity in ZnSSubjects: Materials Science (condmat.mtrlsci)
ZnS is a brittle material but shows extraordinary plasticity during mechanical tests performed in complete darkness. This phenomenon is known as the photoplastic effect, whose underlying mechanisms have long been unclear. We study the impact of light, via photoexcited charge carriers, on the dislocation core structure and mobility using firstprinciples calculations. We calculate the core structure and the chargedependent Peierls barriers of the glide set of Shockley partial dislocations in ZnS. Our findings reveal that locally charged dislocations capture excess carriers in the system, leading to core reconstructions that alter the Peierls barrier, resulting in higher barriers and lower mobility for these dislocations. This altered and asymmetric mobility, depending on dislocation character (edge or mixed) and local stoichiometry (Zn or S rich), is responsible for the brittle behavior of ZnS under light exposure and will be reversed in complete darkness.
 [18] arXiv:2406.13047 [pdf, html, other]

Title: Symplectic Representation of the GinzburgLandau TheoryComments: 9 pages, 1 figuresSubjects: Superconductivity (condmat.suprcon); Mathematical Physics (mathph)
In this work, the GinzburgLandau theory is represented on a symplectic manifold with a phase space content. The order parameter is defined by a quasiprobability amplitude, which gives rise to a quasiprobability distribution function, i.e., a Wignertype function. The starting point is the thermal group representation of Euclidean symmetries and gauge symmetry. Wellknown basic results on the behavior of a superconductor are rederived, providing the consistency of representation. The critical superconducting current density is determined and its usual behavior is inferred. The negativety factor associated with the quasidistribution function is analyzed, providing information about the nonclassicality nature of the superconductor state in the region closest to the edge of the superconducting material.
 [19] arXiv:2406.13051 [pdf, other]

Title: Size Effect of Negative Capacitance State and Subthreshold Swing in Van der Waals Ferrielectric FieldEffect TransistorsComments: 40 pages, 6 figures, 4 AppendicesSubjects: Materials Science (condmat.mtrlsci); Applied Physics (physics.appph)
Analytical calculations corroborated by the finite element modelling show that thin films of Van der Waals ferrielectrics covered by a 2Dsemiconductor are promising candidates for the controllable reduction of the dielectric layer capacitance due to the negative capacitance (NC) effect emerging in the ferrielectric film. The NC state is conditioned by energydegenerated polydomain states of the ferrielectric polarization induced in the films under incomplete screening conditions in the presence of a dielectric layer. Calculations performed for the FETtype heterostructure "ferrielectric CuInP2S6 film  2DMoS2 singlelayer  SiO2 dielectric layer" reveal the pronounced size effect of the multilayer capacitance. Derived analytical expressions for the electric polarization and multilayer capacitance allow to predict the thickness range of the dielectric layer and ferrielectric film for which the NC effect is the most pronounced in various Van der Waals ferrielectrics, and the corresponding subthreshold swing becomes much less than the Boltzmann's limit. Obtained results can be useful for the size and temperature control of the NC effect in the steepslope ferrielectric FETs.
 [20] arXiv:2406.13067 [pdf, html, other]

Title: Unified Finiteelement Model for Transient Absorption and Raman Scattering of Vibrating Noble Metal NanoparticlesSubjects: Mesoscale and Nanoscale Physics (condmat.meshall)
Transient absorption and Raman scattering measurements on noble metal nanoparticles offer complimentary information on their vibrational modes and mechanical interactions with their surroundings. We have developed a comprehensive modeling tool for simulating both of these spectra based on COMSOL Multiphysics finiteelement simulation software. This application can be used to predict the spectra for arbitrary geometries and metal compositions, takes into account local changes in dielectric function for the metals, and can model the small vibrational amplitudes of real transient absorption measurements. We present simulation results for gold and silver nanospheres, silver nanocubes, and gold truncated nanocubes, showing the ability to calculate relative peaks heights in Raman spectra and the ability to fit amplitudes of transientabsorption signals to experiment, and showing that Raman spectra can include contributions from modes often neglected due to symmetry considerations.
 [21] arXiv:2406.13070 [pdf, html, other]

Title: Influence of the coating brittleness on the thermomechanical fatigue behavior of a $\beta$NiAl coated R125 Nibased superalloyCapucine Billard, Damien Texier, Matthieu Rambaudon, JeanChristophe Teissedre, Noureddine Bourhila, Dimitri Marquie, Lionel Marcin, Hugo Singer, Vincent MaurelSubjects: Materials Science (condmat.mtrlsci); Applied Physics (physics.appph)
The brittleness of an aluminide diffusion coating protecting a René 125 Nibased polycrystalline superalloy was investigated over a wide range of temperatures in its asreceived and thermally aged form. Isothermal and thermal cycled aging were performed on the coated system at a maximum temperature of 1100 °C. Microstructure evolutions and damage initiation within the coating were characterized. Interrupted tensile tests and thermomechanical fatigue tests were conducted to document critical stressstrain conditions leading to the coating cracking and lifetime for the case of thermomechanical fatigue loading. Advanced digital image correlation and acoustic emission techniques were used to detect coating cracking. Isothermal oxidation or cyclic oxidation led to improved straintofailure due to metallurgical evolutions and also longer fatigue life under thermomechanical fatigue conditions.
 [22] arXiv:2406.13071 [pdf, html, other]

Title: Structural analysis of Gibbs states and metastates in shortrange classical spin glasses: indecomposable metastates, dynamicallyfrozen states, and metasymmetryComments: 69 pages (apologies)Subjects: Statistical Mechanics (condmat.statmech); Disordered Systems and Neural Networks (condmat.disnn); Mathematical Physics (mathph)
We consider shortrange classical spin glasses, or other disordered systems, consisting of Ising spins. For a lowtemperature Gibbs state in infinite size in such a system, for given random bonds, it is controversial whether its decomposition into pure states will be trivial or nontrivial. We undertake a general study of the overall structure of this problem, based on metastates, which are essential to prove the existence of a thermodynamic limit. A metastate is a probability distribution on Gibbs states, for given disorder, that satisfies certain covariance properties. First, we prove that any metastate can be decomposed as a mixture of indecomposable metastates, and that all Gibbs states drawn from an indecomposable metastate are alike macroscopically. Next, we consider stochastic stability of a metastate under random perturbations of the disorder, and prove that any metastate is stochastically stable. Dynamicallyfrozen states play a role in the analysis of Gibbs states drawn from a metastate, either as states or as parts of states. Using a mapping into real Hilbert space, we prove results about Gibbs states, and classify them into six types. Any indecomposable metastate has a compact symmetry group, though it may be trivial; we call this a metasymmetry. Metastateaverage states are studied, and can be related to states arising dynamically at long times after a quench from high temperature, under some conditions. Many features that are permitted by general results are already present in replica symmetry breaking (RSB). Our results are for cases both with and without spinflip symmetry of the Hamiltonian and, technically, we use mixed $p$spininteraction models.
 [23] arXiv:2406.13076 [pdf, html, other]

Title: The interplay between a pseudogap and superconductivity in a twodimensional Hubbard modelComments: 16 pages, 9 figuresJournalref: Phys. Lett. A 517 (2024), 129656Subjects: Strongly Correlated Electrons (condmat.strel); Superconductivity (condmat.suprcon)
Strongly correlated electrons systems may exhibit a variety of interesting phenomena, for instance, superconductivity and pseudogap, as is the case of cuprates and pnictides. In strongly correlated electron systems, it is considered essential to understand, not only the nature of the pseudogap, but also the relationship between superconductivity and the pseudogap. In order to address this question, in the present work, we investigated a oneband Hubbard model treated by the Green's function method within an npole approximation. In the strongly correlated regime, antiferromagnetic correlations give rise to nearly flat band regions in the nodal points of the quasiparticle bands. As a consequence, a pseudogap emerges at the antinodal points of the Fermi surface. The obtained results indicate that the same antiferromagnetic correlations responsible for a pseudogap, can also favor superconductivity, providing an increase in the superconducting critical temperature Tc.
 [24] arXiv:2406.13096 [pdf, other]

Title: Electric field enhances the electronic and diffusion properties of pentagraphene nanoribbons for application in lithiumion batteries: a firstprinciples studyThi Nhan Tran, Nguyen Vo Anh Duy, Nguyen Hoang Hieu, Truc Anh Nguyen, Nguyen To Van, Viet Bac Thi Phung, Peter Schall, Minh Triet DangComments: 21 pages, 5 figuresSubjects: Materials Science (condmat.mtrlsci); Computational Physics (physics.compph)
Enhancing the electronic and diffusion properties of lithiumion batteries is crucial for improving the performance of the fastgrowing energy storage devices. Here we use first principles methods with density functional theory and the climbing imagenudged elastic band method to evaluate the impact of an external electric field on the stability, electronic and diffusion properties of pentagraphene nanoribbons upon lithium adsorption. We show that by adsorbing a lithium atom, these semiconductor nanoribbons become metal with a formation energy of 0.22 (eV). The diffusion coefficient of this material is five orders of magnitude higher than that of a common carbon graphite layer. Under a relatively small vertical electric field, these lithiumion systems are even more stable, and their diffusion coefficient is enhanced significantly of 711 times higher than that of the material in the absence of an applied electric field and 520 times higher than in the case of commercial graphitic carbon layers. Our results highlight the role of an external electric field as a novel switch to improve the efficiency of lithiumion batteries with pentagraphene nanoribbon electrodes and open a new horizon for the use of more environmentally friendly pentagonal materials as electrode materials in lithiumion battery industry.
 [25] arXiv:2406.13097 [pdf, other]

Title: Can it be detected? A computational protocol for evaluating MOFmetal oxide chemiresistive sensors for early disease detectionComments: 20 pages with 22 pages of supporting information. 7 figures and 1 table. In preparation for submission to a journalSubjects: Materials Science (condmat.mtrlsci)
Human breath contains over 3000 volatile organic compounds, abnormal concentrations of which can indicate the presence of certain diseases. Recently, metalorganic framework (MOF)metal oxide composite materials have been explored for chemiresistive sensor applications, however their ability to detect breath compounds associated with specific diseases remains unknown. In this work, we present a new highthroughput computational protocol for evaluating the sensing ability of MOFmetal oxide towards small organic compounds. This protocol uses a clusterbased method for accelerated structure relaxation, and a combination of binding energies and densityofstates analysis to evaluate sensing ability, the latter measured using Wasserstein distances. We apply this protocol to the case of the MOFmetal oxide composite material NM125TiO2 and show that it is consistent with previously reported experimental results for this system. We examine the sensing ability of NM125TiO2 for over 100 humanbreath compounds spanning 13 different diseases. Statistical inference then allows us to identifies ones which subsequent experimental efforts should focus on. Overall, this work provides new tools for computational sensor research, while also illustrating how computational materials science can be integrated into the field of preventative medicine.
 [26] arXiv:2406.13100 [pdf, html, other]

Title: Understanding the Influence of Hydrogen on BCC Iron Grain Boundaries using the Kinetic Activation Relaxation technique (kART)Comments: 12 pages, 10 FiguresSubjects: Materials Science (condmat.mtrlsci)
Hydrogen embrittlement (HE) poses a significant challenge in the mechanical integrity of iron and its alloys. This study explores the influence of hydrogen atoms on two distinct grain boundaries (GBs), $\Sigma37$ and $\Sigma3$, in bodycenteredcubic (BCC) iron. Using the kinetic activationrelaxation technique (kART), an offlattice kinetic Monte Carlo approach, we examine diffusion barriers and mechanisms associated with these GBs. Our findings reveal distinct behaviors of hydrogen in different GB environments, emphasizing the elastic deformation that arises around the GB in the presence of H that leads to either the predominance of new pathways and diffusion routes or a pinning effect of H atoms. We find that, for these systems, while GB is energetically favorable for H, this element diffuses more slowly at the GBs than in the bulk. Moreover, with detailed information about the evolution landscape around GB, we find that the saturation of a GB with hydrogen both stabilizes the GB by shifting barriers associated with Fe diffusion to higher energies and smooths the energy landscape, reducing the number of diffusion events. This comprehensive analysis enhances our understanding of hydrogen's role in GB behavior, contributing valuable insights for the design and optimization of materials in hydrogenrelated applications.
 [27] arXiv:2406.13102 [pdf, html, other]

Title: On the trapped magnetic moment in typeII superconductorsSubjects: Superconductivity (condmat.suprcon)
Measurements of the trapped (remanent) magnetic moment, $M_{trap}\left(H\right)$, when a small magnetic field $H$ is turned off after cooling below the superconducting transition temperature, $T_c$, or ramping a magnetic field up and down after cooling in a zero field, have advantages in difficult cases of small samples and large fielddependent backgrounds, which is relevant for hydrogenbased ultrahigh$T_{c}$ superconductors (UHTS). Until recently, there was no need for a separate paper on the trapped magnetic flux for wellknown critical state models due to the simplicity of the physics involved. However, recent publications showed the need for such an analysis. This note summarizes the expectations for the Bean model with constant critical current density and the Kim model with fielddependent critical currents. It is shown that if the trapped moment is fitted to the power law, $M_{trap}\propto H^{\alpha}$, the fixed exponent $\alpha=2$ is exact for the Bean model, while Kim models show a wide interval of possible values, $2\leq\alpha\leq4$. Furthermore, accounting for reversible magnetization expands the range of possible exponents to $1\leq\alpha\leq4$. In addition, demagnetizing factors are essential and make the trapped moment orientation dependent even in isotropic materials.
As a concrete application, it is shown that flux trapping experiments on H$_{3}$S UHTS compounds can be described well using this generalized approach, lending further support to the typeII superconducting nature of H$_{3}$S under ultrahigh pressure.  [28] arXiv:2406.13142 [pdf, html, other]

Title: Optimal pretrain/finetune strategies for accurate material property predictionsSubjects: Materials Science (condmat.mtrlsci)
Overcoming the challenge of limited data availability within materials science is crucial for the broadbased applicability of machine learning within materials science. One pathway to overcome this limited data availability is to use the framework of transfer learning (TL), where a pretrained (PT) machine learning model (on a larger dataset) can be finetuned (FT) on a target (typically smaller) dataset. Our study systematically explores the effectiveness of various PT/FT strategies to learn and predict material properties with limited data. Specifically, we leverage graph neural networks (GNNs) to PT/FT on seven diverse curated materials datasets, encompassing sizes ranging from 941 to 132,752 datapoints. We consider datasets that cover a spectrum of material properties, ranging from band gaps (electronic) to formation energies (thermodynamic) and shear moduli (mechanical). We study the influence of PT and FT dataset sizes, strategies that can be employed for FT, and other hyperparameters on pairwise TL among the datasets considered. We find our pairwise PTFT models to consistently outperform models trained from scratch on the target datasets. Importantly, we develop a GNN framework that is simultaneously PT on multiple properties (MPT), enabling the construction of generalized GNN models. Our MPT models outperform pairwise PTFT models on several datasets considered, and more significantly, on a 2D material band gap dataset that is completely outofdistribution from the PT datasets. Finally, we expect our PT/FT and MPT frameworks to be generalizable to other GNNs and materials properties, which can accelerate materials design and discovery for various applications.
 [29] arXiv:2406.13163 [pdf, html, other]

Title: LLMatDesign: Autonomous Materials Discovery with Large Language ModelsSubjects: Materials Science (condmat.mtrlsci); Artificial Intelligence (cs.AI); Computation and Language (cs.CL)
Discovering new materials can have significant scientific and technological implications but remains a challenging problem today due to the enormity of the chemical space. Recent advances in machine learning have enabled datadriven methods to rapidly screen or generate promising materials, but these methods still depend heavily on very large quantities of training data and often lack the flexibility and chemical understanding often desired in materials discovery. We introduce LLMatDesign, a novel languagebased framework for interpretable materials design powered by large language models (LLMs). LLMatDesign utilizes LLM agents to translate human instructions, apply modifications to materials, and evaluate outcomes using provided tools. By incorporating selfreflection on its previous decisions, LLMatDesign adapts rapidly to new tasks and conditions in a zeroshot manner. A systematic evaluation of LLMatDesign on several materials design tasks, in silico, validates LLMatDesign's effectiveness in developing new materials with userdefined target properties in the small data regime. Our framework demonstrates the remarkable potential of autonomous LLMguided materials discovery in the computational setting and towards selfdriving laboratories in the future.
 [30] arXiv:2406.13164 [pdf, html, other]

Title: Magnetoresistance hysteresis in the superconduting state of Kagome CsV$_3$Sb$_5$Comments: 9 pages, 3 figuresSubjects: Superconductivity (condmat.suprcon); Mesoscale and Nanoscale Physics (condmat.meshall); Materials Science (condmat.mtrlsci)
The hysteresis of magnetoresistance observed in superconductors is of great interest due to its potential connection with unconventional superconductivity. In this study, we perform electrical transport measurements on Kagome superconductor CsV$_3$Sb$_5$ nanoflakes and uncover unusual hysteretic behaviour of magnetoresistance in the superconducting state. This hysteresis can be induced by applying either a large DC or AC current at temperatures ($T$) well below the superconducting transition temperature ($T_{\rm c}$). As $T$ approaches $T_{\rm c}$, similar weak hysteresis is also be detected by applying a small current. Various scenarios are discussed, with particular focus on the effects of vortex pinning and the presence of timereversalsymmterybreaking superconducting domains. Our findings support the latter, hinting at chiral superconductivity in Kagome superconductors.
 [31] arXiv:2406.13178 [pdf, html, other]

Title: Efficient Modelling of Anharmonicity and Quantum Effects in PdCuH$_2$ with Machine Learning PotentialsSubjects: Superconductivity (condmat.suprcon)
Quantum nuclear effects and anharmonicity impact a wide range of functional materials and their properties. One of the most powerful techniques to model these effects is the Stochastic SelfConsistent Harmonic Approximation (SSCHA). Unfortunately, the SSCHA is extremely computationally expensive, prohibiting its routine use. We propose a protocol that pairs machine learning interatomic potentials, which can be tailored for the system at hand via active learning, with the SSCHA. Our method leverages an upscaling procedure that allows for the treatment of supercells of up to thousands of atoms with practically minimal computational effort. The protocol is applied to PdCuH$_x$ ($x = 02$) compounds, chosen because previous experimental studies have reported superconducting critical temperatures, $T_\text{c}$s, as high as 17~K at ambient pressures in an unknown hydrogenated PdCu phase. We identify a $P4/mmm$ PdCuH$_2$ structure, which is shown to be dynamically stable only upon the inclusion of quantum fluctuations, as being a key contributor to the measured superconductivity. For this system, our methodology is able to reduce the computational expense for the SSCHA calculations by $\sim$96\%. The proposed protocol opens the door towards the routine inclusion of quantum nuclear motion and anharmonicity in materials discovery.
 [32] arXiv:2406.13203 [pdf, other]

Title: Dynamical phasefield model of cavity electromagnonic systemsSubjects: Mesoscale and Nanoscale Physics (condmat.meshall); Materials Science (condmat.mtrlsci); Applied Physics (physics.appph)
Cavity electromagnonic system, which simultaneously consists of cavities for photons, magnons (quanta of spin waves), and acoustic phonons, provides an exciting platform to achieve coherent energy transduction among different physical systems down to single quantum level. Here we report a dynamical phasefield model that allows simulating the coupled dynamics of the electromagnetic waves, magnetization, and strain in 3D multiphase systems. As examples of application, we computationally demonstrate the excitation of hybrid magnonphoton modes (magnon polaritons), Floquetinduced magnonic AulterTownes splitting, dynamical energy exchange (Rabi oscillation) and relative phase control (Ramsey interference) between the two magnon polariton modes. The simulation results are consistent with analytical calculations based on Floquet Hamiltonian theory. Simulations are also performed to design a cavity electromagnomechanical system that enables the triple phononmagnonphoton resonance, where the resonant excitation of a chiral, fundamental (n=1) transverse acoustic phonon mode by magnon polaritons is demonstrated. With the capability to predict coupling strength, dissipation rates, and temporal evolution of photon/magnon/phonon mode profiles using fundamental materials parameters as the inputs, the present dynamical phasefield model represents a valuable computational tool to guide the fabrication of the cavity electromagnonic system and the design of operating conditions for applications in quantum sensing, transduction, and communication.
 [33] arXiv:2406.13206 [pdf, other]

Title: Two dimensional magnets: Forgotten history and recent progress towards spintronic applicationsDavid L. Cortie, Grace L. Causer, Kirrily C. Rule, Helmut Fritzsche, Wolfgang Kreuzpaintner, Frank KloseComments: 28 pages, 7 figuresJournalref: Adv. Funct. Mater. 2020, 30, 1901414Subjects: Materials Science (condmat.mtrlsci); Strongly Correlated Electrons (condmat.strel)
The recent discovery of twodimensional magnetic order in vander Waals materials has stimulated a renaissance in the field of atomicallythin magnets. This has led to promising demonstrations of spintronic functionality such as tunneling magnetoresistance. The frantic pace of this emerging research, however, has also led to some confusion surrounding the underlying phenomena of phase transitions in twodimensional (2D) magnets. In fact, there is a rich history of experimental precedents beginning in the 1960s with quasi2D bulk magnets and progressing to the 1980s using atomicallythin sheets of elemental metals. This review provides a holistic discussion of the current state of knowledge on the three distinct families of lowdimensional magnets: quasi2D, ultrathin films and vander Waals crystals. It highlights the unique opportunities presented by the latest implementation in vander Waals materials. By revisiting the fundamental insights from the field of lowdimensional magnetism, this review will highlight factors that can be used to enhance material performance. For example, the limits imposed on the critical temperature by the MerminWagner theorem can be escaped in three separate ways: magnetocrystalline anisotropy, long range interactions and shape anisotropy. Several recent experimental reports of atomicallythin magnets with Curie temperatures above room temperature are highlighted.
 [34] arXiv:2406.13218 [pdf, html, other]

Title: Lipid membrane domains control actin network viscoelasticityComments: There are 11 pages with four figures in the main text. Ancillary files include a supplemental appendix and three supplemental videos. The supplemental appendix contains three video legends, a supplemental note, and two supplemental figuresSubjects: Soft Condensed Matter (condmat.soft)
The mammalian cell membrane is embedded with biomolecular condensates of protein and lipid clusters, which interact with an underlying viscoelastic cytoskeleton network to organize the cell surface and mechanically interact with the extracellular environment. However, the mechanical and thermodynamic interplay between the viscoelastic network and liquidliquid phase separation of 2dimensional (2D) lipid condensates remains poorly understood. Here, we engineer materials composed of 2D lipid membrane condensates embedded within a thin viscoelastic actin network. The network generates localized anisotropic stresses that deform lipid condensates into triangular morphologies with sharp edges and corners, shapes unseen in 3D composite gels. Kinetic coarsening of phaseseparating lipid condensates accelerates the viscoelastic relaxation of the network, leading to an effectively softer composite material over intermediate timescales. We dynamically manipulate the membrane composition to control the elastictoviscous crossover of the network. Such viscoelastic composite membranes may enable the development of coatings, catalytic surfaces, separation membranes, and other interfaces with tunable spatial organization and plasticity mechanisms.
 [35] arXiv:2406.13245 [pdf, html, other]

Title: Free energy equivalence between meanfield models and nonsparsely diluted meanfield modelsComments: 9 pages, 0 figureSubjects: Disordered Systems and Neural Networks (condmat.disnn); Statistical Mechanics (condmat.statmech); Mathematical Physics (mathph); Probability (math.PR)
We studied nonsparsely diluted meanfield models that differ from sparsely diluted meanfield models, such as the VianaBray model. We prove that the free energy of nonsparsely diluted meanfield models coincides exactly with that of the corresponding meanfield models with different parameters in ferromagnetic and spinglass models composed of any discrete spin $S$ in the thermodynamic limit. Our results are a broad generalization of the results of a previous study [Bovier and Gayrard, J. Stat. Phys. 72, 643 (1993)], where the densely diluted meanfield ferromagnetic Ising model (diluted CurieWeiss model) was analyzed rigorously, and it was proven that its free energy was exactly equivalent to that of the corresponding meanfield model (CurieWeiss model) with different parameters.
 [36] arXiv:2406.13273 [pdf, html, other]

Title: Anisotropic magnetization dynamics in Fe5GeTe2: Role of critical fluctuationsSubjects: Materials Science (condmat.mtrlsci)
We analyze the magnetization dynamics and magnetic anisotropy in bulk single crystalline Fe5GeTe2, a van der Waals 2D ferromagnet, using broadband Ferromagnetic Resonance Spectroscopy. We find sizable anisotropy in the Lande g factor at room temperature which is attributed to anisotropic critical fluctuations and not spinorbit interaction.
 [37] arXiv:2406.13289 [pdf, html, other]

Title: Hubbard model on a triangular lattice at finite temperaturesComments: 15 pages, 5 figuresSubjects: Strongly Correlated Electrons (condmat.strel)
Using the strong coupling diagram technique, we find three phases of the halffilled isotropic Hubbard model on a triangular lattice at finite temperatures. The weakinteraction ($U\lesssim5t$) and stronginteraction ($U\gtrsim9t$) phases are similar to those obtained by zerotemperature methods  the former is a metal without perceptible spin excitations; the latter is a Mott insulator with the 120$^\circ$ shortrange spin ordering. Zerotemperature approaches predict a nonmagnetic insulating spinliquid phase sandwiched between these two regions. In our finitetemperature calculations, the Mott gap in the intermediate phase is filled by the Fermilevel peak, which is a manifestation of the bound states of electrons with pronounced spin excitations. We relate the appearance of these excitations at finite temperatures to the Pomeranchuk effect.
 [38] arXiv:2406.13297 [pdf, other]

Title: Certification Grade Quantum Dot Luminescent Solar Concentrator Glazing with Optical Communication Capability for Connected Sustainable ArchitectureFrancesco Meinardi, Francesco Bruni, Claudio Castellan, Marco Meucci, Ali Muhammad Umair, Marcello La Rosa, Jacopo Catani, Sergio BrovelliJournalref: Advanced Energy Materials 2024, 14, 2304006Subjects: Materials Science (condmat.mtrlsci)
Energy sustainability and interconnectivity are the two main pillars on which cuttingedge architecture is based and require the realisation of energy and intelligent devices that can be fully integrated into buildings, capable of meeting stringent regulatory requirements and operating in realworld conditions. Luminescent solar concentrators, particularly those based on nearinfrared emitting reabsorptionfree quantum dots, are considered good candidates for the realisation of semitransparent photovoltaic glazing, but despite important advances in optical property engineering strategies, studies of finished devices suitable for realworld operation are still lacking. In this paper, we demonstrate the first example of a fully assembled quantum dot luminescent solar concentratorbased photovoltaic glazing that meets all international standards for photovoltaic and building elements. We also show that these devices are capable of functioning as efficient Visible Light Communication (VLC) receivers even under full sunlight, thus combining energy and wireless connectivity functions in a realistic solution for smart, sustainable buildings.
 [39] arXiv:2406.13313 [pdf, other]

Title: Solutiondependent electrostatic spray deposition (ESD) ZnO thin film growth processesComments: 20 pages, 7 figuresSubjects: Materials Science (condmat.mtrlsci)
The present study describes a facile route of zinc oxide (ZnO) grows using the solutiondependent electrostatic spray deposition (ESD) method at temperatures ranging from 300 °C  500 °C. In this work, zinc chloride (ZnCl2) was dissolved in ethanol (CH3CH2OH) to prepare the 0.1 M concentration of 20 ml for spray solution by ESD. Adding different deionized water (H2O) ratio, three different solutions were prepared. The results reveal that adding H2O ration, suppressing the caxis crystal growth of ZnO thin films. The adhesion of anions was believed to be responsible for this suppression. XRD texture analysis examined the preferred orientations of the (100) and (002) planes of the ZnO thin films. Microstructural parameters namely, lattice parameters, bond length, positional parameters, full width at half maximum, crystallite sizes, lattice strain, and lattice dislocation density, are investigated. This research marks a turning point in costeffective industrial and commercial applications for ESDdeposited electronics.
 [40] arXiv:2406.13324 [pdf, html, other]

Title: Quantum Metricinduced Oscillations in Flat BandsSubjects: Mesoscale and Nanoscale Physics (condmat.meshall)
The transport of Bloch electrons under strong fields is traditionally understood through two mechanisms: intraband Bloch oscillations and interband Zener tunneling. Here we propose a new oscillation mechanism induced by the interband quantum metric, which would significantly affect the electron dynamics under strong fields. By considering the multiband dynamics to the second order of the density matrix, we reveal that quantum metricinduced oscillations (QMO) persist regardless of band dispersion, even in exactly flat bands. The resultant drift current can reach a magnitude comparable to the Bloch oscillationsinduced drift current in systems where interband tunneling is negligible. Notably, the {QMO}induced drift current increases linearly with electric field strength under the constraints of timereversal or spatialinversion symmetry, emerging as the primary delocalized current. We further show that both onedimensional and twodimensional superlattices are potential platforms for investigating QMO.
 [41] arXiv:2406.13326 [pdf, other]

Title: Chiral {\pi} Domain Walls Composed of Twin HalfInteger Surface Disclinations in Ferroelectric Nematic Liquid CrystalsShengzhu Yi, Zening Hong, Zhongjie Ma, Chao Zhou, Miao Jiang, Xiang Huang, Mingjun Huang, Satoshi Aya, Rui Zhang, QiHuo WeiSubjects: Soft Condensed Matter (condmat.soft); Mesoscale and Nanoscale Physics (condmat.meshall); Materials Science (condmat.mtrlsci)
Ferroelectric nematic liquid crystals are polar fluids characterized by microscopic orientational ordering and macroscopic spontaneous polarizations. Within these fluids, walls that separate domains of different polarizations are ubiquitous. We demonstrate that the {\pi} walls in films of polar fluids consist of twin halfinteger surface disclinations spaced horizontally, enclosing a subdomain where the polarization exhibits left or righthanded {\pi} twists across the film. The degenerate geometric configurations of these twin disclinations give rise to kinks and antikinks, effectively partitioning subdomains of opposite chirality like Ising chains. The hierarchical topological structures dictate that fielddriven polar switching entails a twostep annihilation process of the disclinations. These findings serve as a cornerstone for comprehending other walls in ferroelectric and ferromagnetic materials, thereby laying the base for domain engineering crucial for advancing their nonlinear and optoelectronic applications.
 [42] arXiv:2406.13347 [pdf, other]

Title: Topological boundary states in engineered quantumdot molecules on the InAs(111)A surfaceComments: 18 pages in total including 16 pages of main text plus figures and legends plus Appendix section and references as well as two pages of Supplemental MaterialSubjects: Mesoscale and Nanoscale Physics (condmat.meshall)
Atom manipulation by scanning tunneling microscopy was used to construct quantum dots on the InAs(111)A surface. Each dot comprised six ionized indium adatoms. The positively charged adatoms create a confining potential acting on surfacestate electrons, leading to the emergence of a bound state associated with the dot. By lining up the dots into Ndot chains with alternating tunnel coupling between them, quantumdot molecules were constructed that revealed electronic boundary states as predicted by the SuSchriefferHeeger (SSH) model of onedimensional topological phases. Dot chains with odd N were constructed such that they host a single end or domainwall state, allowing one to probe the localization of the boundary state on a given sublattice by scanning tunneling spectroscopy. We found probability density also on the forbidden sublattice together with an asymmetric energy spectrum of the chainconfined states. This deviation from the SSH model arises because the dots are charged and create a variation in onsite potential along the chain  which does not remove the boundary states but shifts their energy away from the midgap position. Our results demonstrate that topological boundary states can be created in quantumdot arrays engineered with atomicscale precision.
 [43] arXiv:2406.13368 [pdf, other]

Title: Lewis Acidity and Basicity Diagnostics of Molten Salt for its Properties and Structure Online MonitoringChangzu Zhu, Jia Song, Xiaorui Xu, Chengyu Wang, Yang Tong, Lve Lin, Shaoqiang Guo, Wentao Zhou, Adrien Couet, Yafei WangSubjects: Materials Science (condmat.mtrlsci)
Analogous to the aqueous solution where the pH of the solvent affects its multiple behaviors, the Lewis aciditybasicity of molten salts also greatly influences their thermophysical and thermochemical properties. In the study, we develop ion probes to quantitatively determine the aciditybasicity scale of molten NaClxAlCl3 (x = 1.52.1) salt using insitu ultraviolet visible (UVVis) spectroscopy. With the accumulation of aciditybasicity data of NaClAlCl3 molten salt for a variety of compositions, the correlation between the aciditybasicity of salt and its measured fundamental properties are derived. To understand the physical and chemical features controlling the aciditybasicity variations, the structures of NaClxAlCl3 molten salts with different chemical compositions are investigated in terms of bonded complexes and coordination numbers. The comprehensive understanding of the correlation between composition, aciditybasicity, properties, and structures of molten salt can serve for the full screening and online monitoring of salt melt in extreme environments by simply measuring the salt aciditybasicity as developed in this study.
 [44] arXiv:2406.13377 [pdf, html, other]

Title: Magnetisminduced secondorder nonlinear optical responses in multiferroic BiFeO$_3$Subjects: Materials Science (condmat.mtrlsci)
Nonlinear optical (NLO) responses of noncentrosymmetric nonmagnets have drawn a lot of attention in the past decades because of their significance in materials characterization, green energy and device applications. However, the magnetisminduced NLO responses have rarely been studied so far. In this paper, we first extend the numerical calculation friendly formula by Rashkeev $\textit{et al.}$ [Phys. Rev. B $\textbf{57}$, 3905 (1998)] for second harmonic generation (SHG) in nonmagnetic materials to include magnetic systems and then calculate the magnetisminduced NLO responses of BiFeO$_3$, a multiferroic that exhibits both ferroelectricity and antiferromagnetic (AFM) ordering at room temperature and has a band gap that falls in the visible frequency region. First, we find that the calculated magnetisminduced SHG susceptibilities are large and the SHG intensity is tunable with the reversal of magnetization. In particular, we find a strong magnetic contrast of the SHG signal of approximately 440% at SHG photon energy of 4.82 eV, thus enabling a magnetic control of the SHG in BiFeO$_3$. Also, because of the sensitivity of the SHG signal to the direction of the Néel vector, the SHG can be utilized to detect the reversal of the Néel vector in the AFM materials, which is an important issue for AFM spintronics. Second, the calculated BPVE in BiFeO$_3$ are also strong, being larger than some wellknown NLO compounds such as BaTiO$_3$, GaAs, CdS and CdSe. Finally, we analyse the origins of the prominent features in the NLO response spectra in terms of the calculated quantum geometric quantities. Our interesting findings suggest that the magnetismdriven NLO responses in BiFeO$_3$ are significant, anisotropic and tunable, and that understanding the magnetismdriven components of both SHG and BPVE is essential for their applications in, e.g., multiferroicbased photovoltaic devices.
 [45] arXiv:2406.13382 [pdf, other]

Title: Flexoelectricity in Amorphous Hafnium Oxide (HfO$_2$)Subjects: Materials Science (condmat.mtrlsci); Applied Physics (physics.appph)
Flexoelectricity, inherent in all materials, offers a promising alternative to piezoelectricity for nanoscale actuation and sensing. However, its widespread application faces significant challenges: differentiating flexoelectric effects from those of piezoelectricity and other phenomena, verifying its universality across all material structures and thicknesses, and establishing a comprehensive database of flexoelectric coefficients across different materials. This work introduces a groundbreaking methodology that accurately isolates flexoelectricity from piezoelectric, electrostrictive and electrostatic effects, with a detection threshold extending below 1 fC/m. The robustness of this method is demonstrated through its application to amorphous hafnium oxide (HfO$_2$), successfully measuring a flexoelectric coefficient of 105 $\pm$ 10 pC/m. This measurement signifies the first measurement of flexoelectricity in hafnia, as well as in any amorphous material. Additionally, the study compiles a list of published flexoelectric coefficients, revealing an important insight. The relationship between the flexoelectric coefficient and the material's relative permittivity is better approximated by a quadratic proportionality. This challenges the traditional linear assumption proposed in Kogan's work and opens new avenues for future research in flexoelectric materials.
 [46] arXiv:2406.13387 [pdf, html, other]

Title: Boundary conditions alter density and stress fluctuations in shearthickening suspensionsSubjects: Soft Condensed Matter (condmat.soft)
Discontinuous shear thickening (DST) in dense suspensions is accompanied by significant fluctuations in stress at a fixed shear rate. In this work, normal stress fluctuations are shown to have a onetoone relationship with the formation and dissolution of local highdensity regions. Namely, a burst in the force response corresponds to the spontaneous appearance of inhomogeneity. We observe that boundary conditions can significantly alter the spatiotemporal scale of these fluctuations, from shortlived to more sustained and enduring patterns. We estimate the occurrence frequency R and the average intensity Q of individual bursts/inhomogeneity events. The growth of R with the shear rate is the most rapid for the rigid boundary, whereas Q is nonmonotonic with confinement stiffness. Our results indicate that boundary conditions alter the development of inhomogeneity and thus the stress response under shear.
 [47] arXiv:2406.13389 [pdf, html, other]

Title: Unifying Mixed Gas Adsorption in Molecular Sieve Membranes and MOFs using Machine LearningComments: Accepted in Separation and Purification Technology, on June 16, 2024. Data available at this https URLSubjects: Soft Condensed Matter (condmat.soft); Materials Science (condmat.mtrlsci); Machine Learning (cs.LG); Computational Physics (physics.compph)
Recent machine learning models to accurately obtain gas adsorption isotherms focus on polymers or metalorganic frameworks (MOFs) separately. The difficulty in creating a unified model that can predict the adsorption trends in both types of adsorbents is challenging, owing to the diversity in their chemical structures. Moreover, models trained only on single gas adsorption data are incapable of predicting adsorption isotherms for binary gas mixtures. In this work, we address these problems using feature vectors comprising only the physical properties of the gas mixtures and adsorbents. Our model is trained on adsorption isotherms of both single and binary mixed gases inside carbon molecular sieving membrane (CMSM), together with data available from CoRE MOF database. The trained models are capable of accurately predicting the adsorption trends in both classes of materials, for both pure and binary components. ML architecture designed for one class of material, is not suitable for predicting the other class, even after proper training, signifying that the model must be trained jointly for proper predictions and transferability. The model is used to predict with good accuracy the CO2 uptake inside CALF20 framework. This work opens up a new avenue for predicting complex adsorption processes for gas mixtures in a wide range of materials.
 [48] arXiv:2406.13391 [pdf, html, other]

Title: Connecting Rashba and Dresselhaus spinorbit interactions to inversion asymmetry in perovskite oxide heterostructuresComments: 14 pages, 10 figuresSubjects: Materials Science (condmat.mtrlsci)
Inversion asymmetry, combined with spin orbit interaction, leads to Rashba or Dresselhaus effects, or combinations of them that are promising for technologies based on antiferromagnetic spintronics. Since understanding the exact nature of spinorbit interaction is crucial for developing a technology based on it, mapping the nature of inversion asymmetry with the type of spinorbit interaction becomes the key. We simulate a perovskite oxide heterostructure LaAlO$_3$SrIrO$_3$SrTiO$_3$ preserving the inversion symmetry within density functional theory to demonstrate the relation between the nature of inversion asymmetry and the corresponding Rashba or Dresselhaustype interaction. With progressive distortion in the heterostructure, we find how the structure inversion asymmetry sets in with distorted bond lengths and bond angles, leading to Rashba effect in the system. Further, introduction of tilted IrO$_6$ octahedra leads to bulk inversion asymmetry, helping a combined RashbaDresselhaus interaction to set in. A comparison of the spin textures obtained from our DFT calculations and theoretical modeling helps us identify the exact nature of the interactions. Besides demonstrating the connection between the nature of asymmetry with Rashba and Dresselhaus interactions, our work may serve as a guide to identifying different types of Rashbalike spinorbit interactions.
 [49] arXiv:2406.13407 [pdf, html, other]

Title: Predicting BN analogue of 8164 graphyne: \textit{In silico} insights into its structural, electronic, optical, and thermal transport propertiesIsaac M. Félix, Jessé M. Pontes, Djardiel S. Gomes, Thiago B. G. Guerra, Sérgio A. F. Azevedo, Leonardo D. Machado, Lídia C. Gomes, Raphael M. TromerSubjects: Materials Science (condmat.mtrlsci)
The boron nitride (BN) analogue of 8164 graphyne, termed SBNyne, is proposed for the first time. Its physical properties were explored using firstprinciples calculations and classical molecular dynamics (MD) simulations. Thermal stability assessments reveal that SBNyne maintains structural integrity up to 1000 K. We found that SBNyne exhibits a wide indirect bandgap of 4.58 eV using HSE06 and 3.20 eV using PBE. It displays strong optical absorption in the ultraviolet region while remaining transparent in the infrared and visible regions. Additionally, SBNyne exhibits significantly lower thermal conductivity compared to hBN. Phonon spectrum analysis indicates that outofplane phonons predominantly contribute to the vibrational density of states only at very low frequencies, explaining its low thermal conductivity. These findings expand the knowledge of BNbased 2D materials and open new avenues for their design and advanced technological applications.
 [50] arXiv:2406.13429 [pdf, other]

Title: Quasiparticles with fractional charges in fractionally filled systemsComments: 12 pages, 5 figuresSubjects: Mesoscale and Nanoscale Physics (condmat.meshall)
We study systems that approach a state possessing discrete symmetry due to different degenerate realizations for the system. For concreteness, we consider fractionally filled systems where degeneracy comes from the presence of identical sublattices. We show that such systems possess a new type of quasiparticles with fractional charges, which we refer to as fractyons. We discuss static and dynamic properties of these quasiparticles.
 [51] arXiv:2406.13435 [pdf, html, other]

Title: An Attempt to Derive the Expression of the Constant in the Thermodynamic Uncertainty Relations by a Statistical Model for a QuasiIdeal NanoGasComments: 11 pages, 1 FigureSubjects: Mesoscale and Nanoscale Physics (condmat.meshall)
In recent work, we have shown that fundamental quantities such as the total entropy production, the thermodynamic variables conjugate to the thermodynamic forces, and the GlansdorffPrigogine's dissipative variable may be discretized at the mesoscopic scale. The Canonical Commutation Rules (CCRs) valid at the mesoscopic scale have been postulated and the measurement process consists of determining the eigenvalues of the operators associated with the thermodynamic quantities. The essence of that work was to analyze the consequences of these postulates. This letter aims to understand the physical nature of the new constant (beta) introduced in the CCRs. In particular, two questions are still open. Is beta a new fundamental constant? Does the constant in the CCRs correspond to the lowest limit? We shall tackle the problem starting from the simplest assumption: the expression of beta can be derived from a simple model (a heuristic model) for nanogas and studied through the tools of classical statistical physics. We will find that the theoretical value is very close to the experimental one. We shall not go further in our interpretation; we shall limit ourselves simply by noticing that according to our model, the constant beta does not appear to be a new fundamental constant but corresponds to the minimum value.
 [52] arXiv:2406.13442 [pdf, html, other]

Title: Designing necks and wrinkles in inflated auxetic membranesJournalref: International Journal of Mechanical Sciences 268 (2024) 109031Subjects: Soft Condensed Matter (condmat.soft); Pattern Formation and Solitons (nlin.PS)
This article presents the potentiality of inflatable, functionallygraded auxetic membranes to produce wrinkles and necks. We obtain elastic instabilities at desired locations in axisymmetric membranes and with prescribed patterns in square membranes. First, we use an analytical approach to obtain a series of universal results providing insights into the formation of wrinkles and necks in inflated, axisymmetric membranes. For example, we prove analytically that necks and wrinkles may never overlap in pressurized, axially symmetric membranes. Second, we implement the relaxed strain energy of tension field theory into a Finite Element solver (COMSOL). By tuning spatial inhomogeneities of the material moduli, we corroborate our universal results, describe the onset of wrinkling in an averaged way, and also generate nontrivial instabilities at desired locations. This study on membranes with morphing or corrugation on demand has potential applications in Braille reading and haptics.
 [53] arXiv:2406.13483 [pdf, html, other]

Title: Voltagecontrolled nonaxisymmetric vibrations of soft electroactive tubes with strainstiffening effectJournalref: International Journal of Solids and Structures 290 (2024) 112671Subjects: Soft Condensed Matter (condmat.soft); Pattern Formation and Solitons (nlin.PS)
Material properties of soft electroactive (SEA) structures are significantly sensitive to external electromechanical biasing fields (such as prestretch and electric stimuli), which generate remarkable knockon effects on their dynamic characteristics. In this work, we analyze the electrostatically tunable nonaxisymmetric vibrations of an incompressible SEA cylindrical tube under the combination of a radially applied electric voltage and an axial prestretch. Following the theory of nonlinear electroelasticity and the associated linearized theory for superimposed perturbations, we derive the nonlinear static response of the SEA tube to the inhomogeneous biasing fields for the Gent ideal dielectric model. Using the State Space Method, we efficiently obtain the frequency equations for voltagecontrolled smallamplitude threedimensional nonaxisymmetric vibrations, covering a wide range of behaviors, from the purely radial breathing mode to torsional modes, axisymmetric longitudinal modes, and prismatic diffuse modes. We also perform an exhaustive numerical analysis to validate the proposed approach compared with the conventional displacement method, as well as to elucidate the influences of the applied voltage, axial prestretch, and strainstiffening effect on the nonlinear static response and vibration behaviors of the SEA tube. The present study clearly indicates that manipulating electromechanical biasing fields is a feasible way to tune the smallamplitude vibration characteristics of an SEA tube. The results should benefit experimental work on, and design of, voltagecontrolled resonant devices made of SEA tubes.
 [54] arXiv:2406.13504 [pdf, html, other]

Title: Selforganized transport in noisy dynamic networksComments: 12 pages, 10 figuresSubjects: Statistical Mechanics (condmat.statmech); Adaptation and SelfOrganizing Systems (nlin.AO); Biological Physics (physics.bioph); Neurons and Cognition (qbio.NC)
We present a numerical study of multicommodity transport in a noisy, nonlinear network. The nonlinearity determines the dynamics of the edge capacities, which can be amplified or suppressed depending on the local current flowing across an edge. We consider network selforganization for three different nonlinear functions: For all three we identify parameter regimes where noise leads to selforganization into more robust topologies, that are not found by the sole noiseless dynamics. Moreover, the interplay between noise and specific functional behavior of the nonlinearity gives rise to different features, such as (i) continuous or discontinuous responses to the demand strength and (ii) either single or multistable solutions. Our study shows the crucial role of the activation function on noiseassisted phenomena.
 [55] arXiv:2406.13509 [pdf, html, other]

Title: A higherdimensional geometrical approach for the classification of 2D squaretrianglerhombus tilingsSubjects: Materials Science (condmat.mtrlsci)
Squaretrianglerhombus ($\mathcal{STR}$) tilings are encountered in various selforganized multicomponent systems. They exhibit a rich structural diversity, encompassing both periodic tilings and longrange ordered quasicrystals, depending on the proportions of the three tiles and their orientation distributions. We derive a general scheme for characterizing $\mathcal{STR}$ tilings based on their lift into a fourdimensional hyperspace. In this approach, the average hyperslope ($2 \times 2$) matrix $\mathcal{H}$ of a patch defines its global composition with four real coefficients: $\mathcal{X}$, $\mathcal{Y}$, $\mathcal{Z}$, and $\mathcal{W}$. The matrix $\mathcal{H}$ can be computed either directly from the areaweighted average of the hyperslopes of individual tiles or indirectly from the border of the patch alone. The coefficient $\mathcal{W}$ plays a special role as it depends solely on the rhombus tiles and encapsulates a topological charge, which remains invariant upon local reconstructions in the tiling. For instance, a square can transform into a pair of rhombuses with opposite topological charges, giving rise to local modes with five degrees of freedom. We exemplify this classification scheme for $\mathcal{STR}$ tilings through its application to experimental structures observed in twodimensional BaTiO films on metal substrates, demonstrating the hyperslope matrix $\mathcal{H}$ as a precise tool for structural analysis and characterization.
 [56] arXiv:2406.13518 [pdf, html, other]

Title: Multiband transport in RuO$_2$Florent Pawula (1 and 2), Ali Fakih (1), Ramzy Daou (1), Sylvie Hébert (1), Natalia Mordvinova (1), Oleg Lebedev (1), Denis Pelloquin (1), Antoine Maignan (1) ((1) CRISMAT Caen, (2) IMN Nantes)Subjects: Materials Science (condmat.mtrlsci)
We present electrical and thermal transport measurements in single crystals of the metallic oxide RuO$_2$. The resistivity and Seebeck coefficient measured up to 970K confirm the metallic nature of transport. Magnetoresistance and Hall effect measurements as a function of orientation can be most easily described by a multiband transport model. We find that the ordinary Hall effect dominates any anomalous Hall signal in single crystals.
 [57] arXiv:2406.13534 [pdf, html, other]

Title: Electric field manipulation of magnetization in an insulating dilute ferromagnet through piezoelectromagnetic couplingD. Sztenkiel, K. Gas, N. Gonzalez Szwacki, M. Foltyn, C. Sliwa, T. Wojciechowski, J. Z. Domagala, D. Hommel, M. Sawicki, T. DietlComments: 18 pages, 10 FiguresSubjects: Materials Science (condmat.mtrlsci)
We report magnetization changes generated by an electric field in ferromagnetic Ga$_{1x}$Mn$_x$N grown by molecular beam epitaxy. Two classes of phenomena have been revealed. First, over a wide range of magnetic fields, the magnetoelectric signal is odd in the electric field and reversible. Employing a macroscopic spin model and atomistic LandauLifshitzGilbert theory with Langevin dynamics, we demonstrate that the magnetoelectric response results from the inverse piezoelectric effect that changes the trigonal singleion magnetocrystalline anisotropy. Second, in the metastable regime of ferromagnetic hystereses, the magnetoelectric effect becomes nonlinear and irreversible in response to a timedependent electric field, which can reorient the magnetization direction. Interestingly, our observations are similar to those reported for another dilute ferromagnetic semiconductor Cr$_x$(Bi$_{1y}$Sb$_y$)$_{1x}$Te$_3$, in which magnetization was monitored as a function of the gate electric field. Those results constitute experimental support for theories describing the effects of timedependent perturbation upon glasses far from thermal equilibrium in terms of an enhanced effective temperature.
 [58] arXiv:2406.13535 [pdf, html, other]

Title: Quasiperiodic potential induced corner states in a quadrupolar insulatorComments: 9 pages, 14 figuresSubjects: Mesoscale and Nanoscale Physics (condmat.meshall)
We systematically investigate the topological and localization properties of a quadrupolar insulator represented by the celebrated BenalcazarBernevigHughes model in presence of a quasiperiodic disorder instilled in its hopping amplitude. While disorder can be detrimental to the existence of the topological order in a system, we observe the emergence of a disorder driven topological phase where the original (clean) system demonstrates trivial behavior. This phenomenon is confirmed by the reemergence of zero energy states in the bandstructure together with a nonzero bulk quadrupole moment, which in turn establishes the bulk boundary correspondence (BBC). Furthermore, the distribution of the excess electronic charge shows a pattern that is reminiscent of the bulk quadrupole topology. To delve into the localization properties of the midband states, we compute the inverse participation and normalized participation ratios. It is observed that the ingap states become critical (multifractal) at the point that discerns a transition from a topological localized to a trivial localized phase. Finally, we carry out a similar investigation to ascertain the effect of the quasiperiodic disorder on the quadrupolar insulator when the model exhibits topological properties in the absence of disorder. Again, we note a multifractal behavior of the eigenstates in the vicinity of the transition.
 [59] arXiv:2406.13541 [pdf, html, other]

Title: Pairing amplification induced by nonadiabatic effects on the electronphonon interaction throughout the BCSBEC crossoverComments: 11 pages, 5 figuresSubjects: Superconductivity (condmat.suprcon)
Nonadiabatic effects in the electronphonon coupling are important whenever the ratio between the phononic and the electronic energy scales, the adiabatic ratio, is non negligible. For superconducting systems, this gives rise to additional diagrams in the superconducting selfenergy, the vertex and cross corrections. In this work we explore these corrections in a twodimensional singleband system through the crossover between the weakcoupling BCS and strongcoupling BoseEinstein regimes. By focusing on the pseudogap phase, we identify the parameter range in which the pairing amplitude is amplified by nonadiabatic effects and map them throughout the BCSBEC crossover. These effects become stronger as the system is driven deeply in the crossover regime, for phonon frequencies of the order of the hopping energy and for large enough electronphonon coupling. Finally, we provide the phase space regions in which the effects of nonadiabaticity are more relevant for unconventional superconductors.
 [60] arXiv:2406.13548 [pdf, html, other]

Title: Dynamical Instabilities of Strongly Interacting Ultracold Fermions in an Optical CavityFilip Marijanović, Sambuddha Chattopadhyay, Luka Skolc, Timo Zwettler, CatalinMihai Halati, Simon B. Jäger, Thierry Giamarchi, JeanPhilippe Brantut, Eugene DemlerSubjects: Quantum Gases (condmat.quantgas); Atomic Physics (physics.atomph)
Recent quench experiments on ultra cold fermions in optical cavities provide a clean platform for studying how longrange interactions between fermions structure their dynamics. Motivated by these experiments, we provide a theoretical analysis of the dynamical instabilities that lead to the formation of superradiance as the hybrid system is driven across the selforganization transition. We compute the rate at which order forms and quantify the fluctuations of the prequench state which seed the instability. Our results quantitatively match existing experiments on free fermions and make predictions for quench experiments involving near unitary fermi gases coupled to an optical cavity. Our work suggests that the nonlocal nature of the photonmediated interactions between fermions generates ordering dynamics that are qualitatively different than those observed in shortrange interacting systems.
 [61] arXiv:2406.13550 [pdf, other]

Title: Local structure maturation in high entropy oxide (Mg,Co,Ni,Cu,Zn)1x(Cr,Mn)xO thin filmsGabriela E. Niculescu, Gerald R. Bejger, John P. Barber, Joshua T. Wright, Saeed S. I. Almishal, Matthew Webb, Sai Venkata Gayathri Ayyagari, JonPaul Maria, Nasim Alem, John T. Heron, Christina M. RostSubjects: Materials Science (condmat.mtrlsci)
High entropy oxides (HEO)s have garnered much interest due to their available high degree of tunability. Here, we study the local structure of (MgNiCuCoZn)0.167(MnCr)0.083O, a composition based on the parent HEO (MgNiCuCoZn)0.2O.We synthesized a series of thin films via pulsed laser deposition at incremental oxygen partial pressures. Xray diffraction shows lattice parameter to decrease with increased pO2 pressures until the onset of phase separation. Xray absorption fine structure shows that specific atomic species in the composition dictate the global structure of the material as Cr, Co, and Mn shift to energetically favorable coordination with increasing pressure. Transmission electron microscopy analysis on a lowerpressure sample exhibits a rock salt structure, but the higherpressure sample reveals reflections reminiscent of the spinel structure. In all, these findings give a more complete picture on how (MgNiCuCoZn)0.167(MnCr)0.083O forms with varying initial conditions and advances fundamental knowledge of cation behavior in high entropy oxides.
 [62] arXiv:2406.13561 [pdf, html, other]

Title: Shape and Size Tunability of Sheets of Interlocked Ring CopolymersComments: Main 15 pages, 9 figuresSubjects: Soft Condensed Matter (condmat.soft); Statistical Mechanics (condmat.statmech)
Mechanically bonded membranes of interlocked ring polymers are a significant generalization of conventional elastic sheets, where connectivity is provided by covalent bonding, and represent a promising class of topological metamaterials. In this context, two open questions regard the largescale reverberations of the heterogeneous composition of the rings and the inequivalent modes of interlocking neighboring rings. We address these questions with Langevin dynamics simulations of chainmails with honeycomblattice connectivity, where the rings are block copolymers with two segments of different rigidity. We considered various combinations of the relative lengths of the two segments and the patterns of the over and underpasses linking neighboring rings. We find that varying ring composition and linking patterns have independent and complementary effects. While the former sets the overall size of the chainmail, the latter defines the shape, enabling the selection of starkly different conformation types. Notably, one of the considered linking patterns favors saddleshaped membranes, providing a first example of spontaneous negative Gaussian curvature in mechanically bonded sheets. The results help establish the extent to which mechanically bonded membranes can differ from conventional elastic membranes, particularly for the achievable shape and size tunability.
 [63] arXiv:2406.13590 [pdf, html, other]

Title: Chirality Effects in Molecular ChainmailComments: 18 pages, 12 figuresSubjects: Soft Condensed Matter (condmat.soft); Statistical Mechanics (condmat.statmech); Differential Geometry (math.DG); General Topology (math.GN)
Motivated by the observation of positive Gaussian curvature in kinetoplast DNA networks, we consider the effect of linking chirality in square lattice molecular chainmail networks using Langevin dynamics simulations and constrained gradient optimization. Linking chirality here refers to ordering of overunder versus underover linkages between a loop and its neighbors. We consider fully alternating linking, maximally nonalternating, and partially nonalternating linking chiralities. We find that in simulations of polymer chainmail networks, the linking chirality dictates the sign of the Gaussian curvature of the final state of the chainmail membranes. Alternating networks have positive Gaussian curvature, similar to what is observed in kinetoplast DNA networks. Maximally nonalternating networks form isotropic membranes with negative Gaussian curvature. Partially nonalternating networks form flat diamondshaped sheets which undergo a thermal folding transition when sufficiently large, similar to the crumpling transition in tethered membranes. We further investigate this topologycurvature relationship on geometric grounds by considering the tightest possible configurations and the constraints that must be satisfied to achieve them.
 [64] arXiv:2406.13609 [pdf, html, other]

Title: 3D Visualization Reveals the Cooling Rate Dependent Crystallization near a Wall in Dense Microgel SystemsComments: Main: 10 pages, 9 figures; SI: 7 pages, 5 figuresSubjects: Soft Condensed Matter (condmat.soft)
Controlled crystallization, melting and vitrification are important fundamental processes in nature and technology. However, the microscopic details of these fundamental phenomena still lack understanding, in particular how the cooling rate and presence of a wall influence the crystal nucleation and glass formation. Thermoresponsive microgels provide the possibility to study phase transitions on a singleparticle level, owing to the ability to tune the particle size with temperature. In this study, we employ composite microgels consisting of a hard core and a crosslinked poly(Nisopropyl acrylamidecomethacrylic acid) shell to study the crystallization of dense suspensions of soft colloids near a wall using confocal microscopy. We investigate the effect of cooling rate on the fluidtosolid transition close to the sample wall. The structures formed during cooling range from glassy in case of a rapid temperature quench, to crystalline when a slow cooling rate is used. Detailed analysis of the final structure reveals that the cooling rate also sets the degree of alignment of the crystal domains with the wall as a result of a balance between homogeneous and heterogenous crystal nucleation. The results presented here yield valuable insight into the microscopic details of temperaturecontrolled crystallization near a wall. This understanding will help pave the way towards optimal crystallization conditions for microgel applications.
 [65] arXiv:2406.13614 [pdf, other]

Title: Relative TimeofFlight Measurement in an Ultrafast Electron MicroscopeSubjects: Materials Science (condmat.mtrlsci)
Efforts to push the spatiotemporal imagingresolution limits of femtosecond (fs) laserdriven ultrafast electron microscopes (UEMs) to the combined angstromfs range will benefit from stable sources capable of generating high bunch charges. Recent demonstration of unconventional offaxis photoemitting geometries are promising, but connections to the observed onset of structural dynamics are yet to be established. Here we use the insitu photoexcitation of coherent phonons to quantify the relative timeofflight (rTOF) of photoelectron packets generated from the Ni Wehnelt aperture and from a Ta cathode setback from the aperture plane. We further support the UEM experiments with particletracing simulations of the precise electrongun architecture and photoemitting geometries. In this way, we measure discernable shifts in electronpacket TOF of tens of picoseconds for the two photoemitting surfaces. These shifts arise from the impact the Wehneltaperture offaxis orientation has on the electronmomentum distribution, which modifies both the collection efficiency and the temporalpacket distribution relative to onaxis emission. Future needs are identified; we expect this and other developments in UEM electrongun configuration to expand the range of materials phenomena that can be directly imaged on scales commensurate with fundamental structural dynamics.
 [66] arXiv:2406.13615 [pdf, html, other]

Title: Landau Level SingleElectron PumpingE. Pyurbeeva, M.D. Blumenthal, J.A. Mol, H. Howe, H. E. Beere, T. Mitchell, D. A. Ritchie, M. PepperComments: 8 pages, 4 figuresSubjects: Mesoscale and Nanoscale Physics (condmat.meshall)
We present the first detailed study of the effect of a strong magnetic field on singleelectron pumping in a device utilising a fingergate splitgate configuration. In the quantum Hall regime, we demonstrate electron pumping from Landau levels in the leads, where the measurements exhibit pronounced oscillations in the lengths of the pumping plateaus with the magnetic field, reminiscent of Shubnikovde Haas oscillations. This similarity indicates that the pumping process is dependent on the density of states of the 2D electron gas over a narrow energy window. Based on these observations, we develop a new theoretical description of the operation of singleelectron pumps which for the first time allows for the determination of the physical parameters of the experiment; such as the capture energy of the electrons, the broadening of the quantised Landau levels in the leads, and the quantum lifetime of the electrons.
 [67] arXiv:2406.13634 [pdf, html, other]

Title: Intertwined superconductivity and orbital selectivity in a threeorbital Hubbard model for the iron pnictidesComments: 7 pages (inclusive of supplemental material), 4 figures in the main text, 3 figures in the supplemental materialSubjects: Strongly Correlated Electrons (condmat.strel); Superconductivity (condmat.suprcon)
We study a threeorbital HubbardKanamori model relevant for ironbased superconductors using variational wave functions, which explicitly include spatial correlations and electron pairing. We span the nonmagnetic sector ranging from a filling $n=4$, which is representative of undoped ironbased superconductors, to $n=3$. In the latter case, a Mott insulating state is found, with each orbital at half filling. In the strongcoupling regime, when the electron density is increased, we find a spontaneous differentiation between the occupation of $d_{xz}$ and $d_{yz}$ orbitals, which leads to an orbitalselective state with a nematic character that becomes stronger at increasing density. One of these orbitals stays half filled for all densities while the other one hosts (together with the $d_{xy}$ orbital) the excess of electron density. Most importantly, in this regime, longrange pairing correlations appear in the orbital with the largest occupation. Our results highlight a strong link between orbitalselective correlations, nematicity, and superconductivity, which requires the presence of a significant Hund's coupling.
 [68] arXiv:2406.13639 [pdf, html, other]

Title: Universal Role of Combined Symmetry for the Protection of the Dirac Cone in Antiferromagnetic Topological InsulatorsAsuka Honma, Noriyuki Kabeya, Seigo Souma, Yongjian Wang, Kunihiko Yamauchi, Kosuke Nakayama, Daichi Takane, Kenichi Ozawa, Miho Kitamura, Koji Horiba, Hiroshi Kumigashira, Tamio Oguchi, Takashi Takahashi, Noriaki Kimura, Yoichi Ando, Takafumi SatoComments: 18 pages, 5 figuresSubjects: Mesoscale and Nanoscale Physics (condmat.meshall); Strongly Correlated Electrons (condmat.strel)
Antiferromagnetic topological insulators (AF TIs) are predicted to exhibit exotic physical properties such as gigantic optical and topological magnetoelectric responses. While a key to achieving such phenomena relies on how to break the symmetry protecting the Diraccone surface state (SS) and acquire the mass of Dirac fermions, the mechanism has yet to be clarified. To address this issue, we carried out microfocused angleresolved photoemission spectroscopy for GdBi hosting the typeII AF order, and uncovered the stripetype 2$\times$1 reconstruction of the Fermi surface associated with the AF band folding. Intriguingly, in contrast to NdBi with the typeI AF order displaying the surfaceselective Diracfermion mass, GdBi shows massless behavior irrespective of AF domains due to the robust topological protection. These results strongly suggest a crucial role of the ThetaTD (timereversal and translational) symmetry to create the Diracfermion mass in AF TIs.
 [69] arXiv:2406.13646 [pdf, html, other]

Title: Traveling Fronts and the Smoothing of the CollectiveMotion Phase Transition in Vibrated Polar DisksJournalref: Physical Review E 109, 054610 (2024)Subjects: Soft Condensed Matter (condmat.soft)
One of the most well known features of active matter is the tendencey of selfpropelled particles to undergo systemwide collective motion. With low enough rotational noise or high enough global density, these systems spontaneously break symmetry and transition to a state with nonzero net momentum. The transition is currently understood as discontinuous, with phase coexistence manifesting in terms of dense travelling bands propagating through a dilute background. Here we show that the phase transition appears continuous in experiments with a system of hundreds of polar vibrated disks, and compare the fluctuations in this system to the traveling bands that are present in larger systems. We argue that this difference is due to finite size effects, which are often considered an artifact of simulations in studies with equilibrium systems, but that are of fundamental importance in many systems of selfpropelled particles such as those composed of living individuals.
 [70] arXiv:2406.13648 [pdf, html, other]

Title: Why Matthiessen's rule is violated in the high$T_{c}$ cuprate superconductors?Comments: 14 pages, 10 figuresSubjects: Strongly Correlated Electrons (condmat.strel); Superconductivity (condmat.suprcon)
The perfect linearin$T$ dc resistivity in the strange metal phase of the high$T_{c}$ cuprate superconductors is probably the most prominent manifestation of their nonFermi liquid nature. A major puzzle about the strange metal behavior is that there is no discernible change in the trend of the dc resistivity at a temperature when we expect the electronphonon coupling to play an essential role. The empirical Matthiessen's rule of summation of the resistivity from different scattering channels seems to be simply violated. On the other hand, the electronphonon coupling has long been proposed to be responsible for the various spectral anomalies observed in the cuprate superconductors. In particular, the $B_{1g}$ buckling mode of the oxygen ion in the $CuO_{2}$ plane is proposed to be responsible for the peakdiphump spectral shape around the antinodal point. Here we show that the coupling to the $B_{1g}$ buckling mode is strongly suppressed by the vertex correction from the antiferromagnetic spin fluctuation in the system as a result of the destructive interference between electronphonon matrix element at momentum differ by the antiferromagnetic wave vector. In the real space scenario, such a destructive interference effect simply amounts to the fact that the electron hopping between nearestneighboring sites is suppressed by the antiferromagnetic spin correlation between the electrons. More generally, we argue that the electronphonon coupling strength in the cuprate superconductors should diminish with the proximity of the Mott insulating phase as a result of similar vertex correction from the electron correlation effect. We think that this offers an interpretation for the violation of the Matthiessen's rule in the dc resistivity of the strange metal phase of the cuprate superconductors.
 [71] arXiv:2406.13649 [pdf, html, other]

Title: Competition of vortex core structures in superfluid $^3$HeBComments: 15 pages, 6 figuresSubjects: Other Condensed Matter (condmat.other)
Among vortex structures identified so far in superfluid $^3$HeB, the most common are the Aphasecore vortex and the doublecore vortex. According to earlier numerical calculations, the doublecore vortex is energetically favored nearly everywhere in the $p$$T$ phase diagram. Nevertheless, in experiments the Aphasecore vortex has been observed down to temperatures of $0.6T_{\mathrm{c}}$ at high pressures. We use the GinzburgLandau formalism to calculate the energies of the two vortex structures in the experimentally relevant magnetic field as well as the energy barrier for the transition between the two structures. Assigning vanishing barrier as the boundary of the metastability region of the Aphasecore vortex, we reproduce the experimentally measured vortex phase diagram and provide an explanation for the reappearance of the doublecore vortex near the critical temperature $T_{\mathrm{c}}$ at low pressures: The difference in Zeeman energy between the two vortex structures becomes relatively more important close to $T_{\mathrm{c}}$, and the Aphasecore vortex becomes unstable. In contrast to the equilibrium vortex structures, we suggest that the vortex nucleation process favors the Aphasecore vortex over the doublecore vortex. Our approach can be used to analyze competition between different vortex structures in other unconventional superfluids and superconductors.
 [72] arXiv:2406.13676 [pdf, html, other]

Title: Oxygen vacancies kinetics in $TaO_{2h}$/$Ta_{2}$$O_{5x}$ memristive interfacesComments: preprint 19 pages, 6 figures. Supp. Material under requestSubjects: Mesoscale and Nanoscale Physics (condmat.meshall)
Oxygen vacancies (OV) are pervasive in metal oxides and play a pivotal role in the switching behaviour of oxidebased memristive devices. In this work we address, through a combination of experiments and theoretical simulations, OV dynamics in $Pt/TaO_{2h}/Ta_{2}O_{5x}/TaO_${2y}$/Pt$ devices. In particular, we focus on the RESET transition (from low to high resistance), induced by the application of electrical pulse(s), by choosing different initial OV profiles and studying their kinetics during the mentioned process. We demonstrate that by selecting specific OV profiles it is possible to tune the characteristic timescale of the RESET. Finally, we show that the implementation of gradual RESETs, induced by applying many (small) successive pulses, allows estimating the activation energies involved in the OV electromigration process. Our results help paving the way for OV engineering aiming at optimizing key memristive figures such as switching speed or power consumption, which are highly relevant for neuromorphic or inmemory computing implementations.
 [73] arXiv:2406.13689 [pdf, html, other]

Title: BoseEinstein condensation of polaritons at room temperature in a GaAs/AlGaAs structureHassan Alnatah, Qi Yao, Qiaochu Wan, Jonathan Beaumariage, Ken West, Kirk Baldwin, Loren N. Pfeiffer, David W. SnokeSubjects: Quantum Gases (condmat.quantgas)
We report the canonical properties of BoseEinstein condensation of polaritons, seen previously in many lowtemperature experiments, at room temperature in a GaAs/AlGaAs structure. These effects include a nonlinear energy shift of the polaritons, showing that they are not noninteracting photons, and dramatic line narrowing due to coherence, giving coherent emission with spectral width of 0.24 meV at room temperature with no external stabilization. This opens up the possibility of room temperature nonlinear optical devices based on polariton condensation.
 [74] arXiv:2406.13702 [pdf, other]

Title: VanHove annihilation and nematic instability on a Kagome latticeYuXiao Jiang, Sen Shao, Wei Xia, M. Michael Denner, Julian Ingham, Md Shafayat Hossain, Qingzheng Qiu, Xiquan Zheng, Hongyu Chen, ZiJia Cheng, Xian P. Yang, Byunghoon Kim, JiaXin Yin, Songbo Zhang, Maksim Litskevich, Qi Zhang, Tyler A. Cochran, Yingying Peng, Guoqing Chang, Yanfeng Guo, Ronny Thomale, Titus Neupert, M. Zahid HasanComments: 19 pages, 5 figures, accepted for publication in Nature materialsSubjects: Strongly Correlated Electrons (condmat.strel); Materials Science (condmat.mtrlsci)
Novel states of matter arise in quantum materials due to strong interactions among electrons. A nematic phase breaks the point group symmetry of the crystal lattice and is known to emerge in correlated materials. Here we report the observation of an intraunitcell nematic order and signatures of Pomeranchuk instability in the Kagome metal ScV6Sn6. Using scanning tunneling microscopy and spectroscopy, we reveal a stripelike nematic order breaking the crystal rotational symmetry within the Kagome lattice itself. Moreover, we identify a set of van Hove singularities adhering to the Kagome layer electrons, which appear along one direction of the Brillouin zone while being annihilated along other highsymmetry directions, revealing a rotational symmetry breaking. Via detailed spectroscopic maps, we further observe an elliptical deformation of Fermi surface, which provides direct evidence for an electronically mediated nematic order. Our work not only bridges the gap between electronic nematicity and Kagome physics, but also sheds light on the potential mechanism for realizing symmetrybroken phases in correlated electron systems.
 [75] arXiv:2406.13740 [pdf, html, other]

Title: Kinetic Inductance, Quantum Geometry, and Superconductivity in MagicAngle Twisted Bilayer GrapheneMiuko Tanaka, Joel Îj. Wang, Thao H. Dinh, Daniel RodanLegrain, Sameia Zaman, Max Hays, Bharath Kannan, Aziza Almanakly, David K. Kim, Bethany M. Niedzielski, Kyle Serniak, Mollie E. Schwartz, Kenji Watanabe, Takashi Taniguchi, Jeffrey A. Grover, Terry P. Orlando, Simon Gustavsson, Pablo JarilloHerrero, William D. OliverSubjects: Superconductivity (condmat.suprcon); Mesoscale and Nanoscale Physics (condmat.meshall); Strongly Correlated Electrons (condmat.strel); Quantum Physics (quantph)
The physics of superconductivity in magicangle twisted bilayer graphene (MATBG) is a topic of keen interest in moiré systems research, and it may provide insight into the pairing mechanism of other strongly correlated materials such as high$T_{\mathrm{c}}$ superconductors. Here, we use DCtransport and microwave circuit quantum electrodynamics (cQED) to measure directly the superfluid stiffness of superconducting MATBG via its kinetic inductance. We find the superfluid stiffness to be much larger than expected from conventional singleband Fermi liquid theory; rather, it aligns well with theory involving quantum geometric effects that are dominant at the magic angle. The temperature dependence of the superfluid stiffness exhibits a powerlaw behavior, which contraindicates an isotropic BCS model; instead, the extracted powerlaw exponents indicate an anisotropic superconducting gap, whether interpreted using the conventional anisotropic BCS model or a quantum geometric theory of flatband superconductivity. Moreover, the quadratic dependence of the stiffness on both DC and microwave current is consistent with GinzburgLandau theory. Taken together, these findings strongly suggest a connection between quantum geometry, superfluid stiffness, and unconventional superconductivity in MATBG. Finally, the combined DCmicrowave measurement platform used here is applicable to the investigation of other atomically thin superconductors.
 [76] arXiv:2406.13742 [pdf, html, other]

Title: Superfluid stiffness of twisted multilayer graphene superconductorsAbhishek Banerjee, Zeyu Hao, Mary Kreidel, Patrick Ledwith, Isabelle Phinney, Jeong Min Park, Andrew M. Zimmerman, Kenji Watanabe, Takashi Taniguchi, Robert M Westervelt, Pablo JarilloHerrero, Pavel A. Volkov, Ashvin Vishwanath, Kin Chung Fong, Philip KimSubjects: Superconductivity (condmat.suprcon); Mesoscale and Nanoscale Physics (condmat.meshall); Strongly Correlated Electrons (condmat.strel); Quantum Physics (quantph)
The robustness of the macroscopic quantum nature of a superconductor can be characterized by the superfluid stiffness, $\rho_s$, a quantity that describes the energy required to vary the phase of the macroscopic quantum wave function. In unconventional superconductors, such as cuprates, the lowtemperature behavior of $\rho_s$ drastically differs from that of conventional superconductors due to quasiparticle excitations from gapless points (nodes) in momentum space. Intensive research on the recently discovered magicangle twisted graphene family has revealed, in addition to superconducting states, strongly correlated electronic states associated with spontaneously broken symmetries, inviting the study of $\rho_s$ to uncover the potentially unconventional nature of its superconductivity. Here we report the measurement of $\rho_s$ in magicangle twisted trilayer graphene (TTG), revealing unconventional nodalgap superconductivity. Utilizing radiofrequency reflectometry techniques to measure the kinetic inductive response of superconducting TTG coupled to a microwave resonator, we find a linear temperature dependence of $\rho_s$ at low temperatures and nonlinear Meissner effects in the current bias dependence, both indicating nodal structures in the superconducting order parameter. Furthermore, the doping dependence shows a linear correlation between the zero temperature $\rho_s$ and the superconducting transition temperature $T_c$, reminiscent of Uemura's relation in cuprates, suggesting phasecoherencelimited superconductivity. Our results provide strong evidence for nodal superconductivity in TTG and put strong constraints on the mechanisms of these graphenebased superconductors.
 [77] arXiv:2406.13769 [pdf, html, other]

Title: Structural and Electronic Properties of Amorphous Silicon and Germanium Monolayers and Nanotubes: A DFT InvestigationComments: 5 pagesSubjects: Materials Science (condmat.mtrlsci)
A recent breakthrough has been achieved by synthesizing monolayer amorphous carbon (MAC), which introduces a material with unique optoelectronic properties. Here, we used ab initio (DFT) molecular dynamics simulations to study silicon and germanium MAC analogs. Typical unit cells contain more than 600 atoms. We also considered their corresponding nanotube structures. The cohesion energy values for MASi and MAGe range from 8.41 to 7.49 eV/atom and follow the energy ordering of silicene and germanene. Their electronic behavior varies from metallic to small band gap semiconductors. Since silicene, germanene, and MAC have already been experimentally realized, the corresponding MAClike versions we propose are within our present synthetic capabilities.
 [78] arXiv:2406.13795 [pdf, html, other]

Title: Perspective: Interactions mediated by atoms, photons, electrons, and excitonsComments: Comments are welcome. 23 pages + 12 figuresSubjects: Quantum Gases (condmat.quantgas); Mesoscale and Nanoscale Physics (condmat.meshall)
Interactions between quasiparticles mediated by a surrounding environment are ubiquitous and lead to a range of important effects from collective modes of low temperature quantum gases, superconductivity, to the interaction between elementary particles at high energies. This perspective article is motivated by experimental progress in the fields of quantum degenerate atomic gases, cavity QED, and twodimensional (2D) semiconductors, which enable a systematic exploration of mediated interactions in new settings and regimes. We first describe how to microscopically calculate the quasiparticle interaction using perturbation theory, diagrammatics, and the path integral, highlighting the key role played by the quantum statistics of the quasiparticles. Recent theoretical and experimental insights into quasiparticle and mediated interactions in general obtained from atomic gases are then discussed, after which we focus on hybrid lightatom systems where a remarkable long range photon mediated interaction can be realised. Next, we describe new and puzzling results regarding the interaction between quasiparticles in 2D semiconductors. We then discuss how mediated interactions open up ways to realise new quantum phases in atomic and hybrid atomphoton systems as well as 2D semiconductors, and the perspective ends by posing some open questions and outlook.
 [79] arXiv:2406.13799 [pdf, other]

Title: Observation of Electronic Viscous Dissipation in Graphene Magnetothermal TransportArtem Talanov, Jonah Waissman, Aaron Hui, Brian Skinner, Kenji Watanabe, Takashi Taniguchi, Philip KimComments: 32 pages, 9 figures, including supplementary informationSubjects: Mesoscale and Nanoscale Physics (condmat.meshall); Strongly Correlated Electrons (condmat.strel)
Hydrodynamic transport effectively describes the collective dynamics of fluids with welldefined thermodynamic quantities. With enhanced electronelectron interactions at elevated temperatures, the collective behavior of electrons in graphene with minimal impurities can be depicted as a hydrodynamic flow of charges. In this new regime, the wellknown rules of Ohmic transport based on a single electron picture no longer apply, necessitating the consideration of collective electron dynamics. In particular, the hydrodynamic analogues of Joule heating and thermal transport require consideration of the viscous motion of the electron fluid, which has a direct impact on energy dissipation and heat generation by the fluidic motion of charge. In this work, we probe graphene hydrodynamics with thermal transport and find two distinct, qualitative signatures: thermal conductivity suppression below the WiedemannFranz value and viscous heating leading to magneticallyinduced redistribution of temperature. We find these two effects are coincident in temperature and density, providing robust qualitative signatures of hydrodynamics, despite arising from two distinct aspects of this new regime: microscopic momentum conservation due to electronelectron scattering, and geometrydependent viscous dissipation. Our results mark the first observation of viscous electronic heating in an electron fluid, providing insight for thermal management in electronic hydrodynamic devices and offering a new methodology for identifying hydrodynamic states in other systems.
 [80] arXiv:2406.13810 [pdf, html, other]

Title: Harvesting Deformation Modes for Micromorphic Homogenization from Experiments on Mechanical MetamaterialsComments: 27 pages, 8 figures, abstract shortened to fulfil 1920 character limitJournalref: International Journal of Solids and Structures 112916 (2024)Subjects: Soft Condensed Matter (condmat.soft)
A micromorphic computational homogenization framework has recently been developed to deal with materials showing longrange correlated interactions, i.e. displaying patterning modes. Typical examples of such materials are elastomeric mechanical metamaterials, in which patterning emerges from local buckling of the underlying microstructure. Because pattern transformations significantly influence the resulting effective behaviour, it is vital to distinguish them from the overall deformation. To this end, the following kinematic decomposition into three parts was introduced in the micromorphic scheme: (i) a smooth mean displacement field, corresponding to the slowly varying deformation at the macroscale, (ii) a longrange correlated fluctuation field, related to the buckling pattern at the mesoscale, and (iii) the remaining uncorrelated local microfluctuation field at the microscale. The micromorphic framework has proven to be capable of predicting relevant mechanical behaviour, including size effects and spatial as well as temporal mixing of patterns in elastomeric metamaterials, making it a powerful tool to design metamaterials for engineering applications. The longrange correlated fluctuation fields need to be, however, provided a priori as input parameters. The main goal of this study is experimental identification of the decomposed kinematics in cellular metamaterials based on the threepart ansatz. To this end, a fullfield micromorphic Integrated Digital Image Correlation (IDIC) technique has been developed. The methodology is formulated for finitesize cellular elastomeric metamaterial specimens deformed in (i) virtually generated images and (ii) experimental images attained during insitu compression of specimens with millimetre sized microstructure using optical microscopy.
 [81] arXiv:2406.13811 [pdf, html, other]

Title: Seasonal footprints on ecological time series and jumps in dynamic states of protein configurations from a nonlinear forecasting method characterizationLeonardo Reyes, Kilver Campos, Douglas Avendaño, Lenin GonzálezPaz, Alejandro Vivas, Ysaías J. Alvarado, Saúl FloresComments: 5 pages, 8 figuresSubjects: Soft Condensed Matter (condmat.soft); Adaptation and SelfOrganizing Systems (nlin.AO)
We have analyzed phenology data and jumps in protein configurations with the nonlinear forecasting method proposed by May and Sugihara \cite{MS90}. Full plots of prediction quality as a function of dimensionality and forecasting time give fast and valuable information about Complex Systems dynamics.
 [82] arXiv:2406.13819 [pdf, html, other]

Title: Magnetochiral vortex ratchet effect in twodimensional arrays of $\varphi_0$Josephson junctionsSimon Reinhardt, AlexanderGeorg Penner, Johanna Berger, Christian Baumgartner, Sergei Gronin, Geoffrey C. Gardner, Tyler Lindemann, Michael J. Manfra, Leonid I. Glazman, Felix von Oppen, Nicola Paradiso, Christoph StrunkComments: 15 pages, 11 FiguresSubjects: Superconductivity (condmat.suprcon)
We demonstrate transport in 2D arrays of multiterminal $\varphi_0$junctions. When applying an inplane magnetic field we observe nonreciprocal vortex depinning currents, induced by a ratchetlike pinning potential. The ratchet effect is explained as a consequence of spontaneous supercurrents that arise in the presence of nextnearest neighbor Josephson couplings. Tuning the density of vortices to commensurate values of the frustration parameter results in an enhancement of the ratchet effect. In addition, we find a surprising sign reversal of the ratchet effect near frustration 1/3.
 [83] arXiv:2406.13825 [pdf, other]

Title: Low frequency noise in nanoparticlemolecule networks and implications for inmaterio reservoir computingComments: Full paper and supporting informationSubjects: Mesoscale and Nanoscale Physics (condmat.meshall); Applied Physics (physics.appph)
We study the lowfrequency noise (LFN), i.e. flicker noise, also referred to as 1/f noise, in 2D networks of molecularly functionalized gold nanoparticles (NMN: nanoparticlemolecule network). We examine the noise behaviors of the NMN hosting alkyl chains (octanethiol), fatty acid oleic acids (oleylamine), redox molecule switches (polyoxometalate derivatives) or photoisomerizable molecules (azobenzene derivatives) and we compare their 1/f noise behaviors. These noise metrics are used to evaluate which molecules are the best candidates to build inmaterio reservoir computing molecular devices based on NMNs.
 [84] arXiv:2406.13859 [pdf, html, other]

Title: Roomtemperature Ferroelectric Control of 2D Layered MagnetismComments: 5 pages, 6 figuresSubjects: Mesoscale and Nanoscale Physics (condmat.meshall)
Electrical tuning of magnetism is crucial for developing fast, compact, ultralow power electronic devices. Multiferroics offer significant potential due to their ability to control magnetic via an electric field through magnetoelectric coupling, especially in layered ferroelectric/ferromagnet heterostructures. A key challenge is achieving reversible and stable switching between distinct magnetic states using a voltage control. In this work, we present ferroelectric tuning of roomtemperature magnetism in a 2D layered ferromagnet. The energyefficient control consumes less than 1 fJ per operation which is normally in the order of several aJ, resulting in a ~43% change in magnetization. This tunable multiferroic interface and associated devices provide promising opportunities for nextgeneration reconfigurable communication systems, spintronics, sensors and memories.
 [85] arXiv:2406.13878 [pdf, html, other]

Title: Role of BathInduced ManyBody Interactions in the Dissipative Phases of the SuSchriefferHeeger ModelComments: 17 pages, 7 figuresSubjects: Mesoscale and Nanoscale Physics (condmat.meshall); Quantum Physics (quantph)
The SuSchriefferHeeger chain is a prototype example of a symmetryprotected topological insulator. Coupling it nonperturbatively to local thermal environments, either through the intercell or the intracell fermion tunneling elements, modifies the topological window. To understand this effect, we employ the recently developed reactioncoordinate polaron transform (RCPT) method, which allows treating systembath interactions at arbitrary strengths. The effective system Hamiltonian, which is obtained via the RCPT, exposes the impact of the baths on the SSH chain through renormalization of tunneling elements and the generation of manybody interaction terms. By performing exact diagonalization and computing the ensemble geometric phase, a topological invariant applicable even to systems at finite temperature, we distinguish the trivial band insulator (BI) from the topological insulator (TI) phases. Furthermore, through the RCPT mapping, we are able to pinpoint the main mechanism behind the extension of the parameter space for the TI or the BI phases (depending on the coupling scheme, intracell or intercell), which is the bathinduced, dimerized, manybody interaction. We also study the effect of onsite staggered potentials on the SSH phase diagram, and discuss extensions of our method to higher dimensions.
 [86] arXiv:2406.13886 [pdf, html, other]

Title: Alternating current Hanle effect as poor man's paramagnetic resonanceComments: 5 pages, 4 figuresSubjects: Materials Science (condmat.mtrlsci)
It is shown that in spin injection experiments the interplay between external magnetic field and alternating current can be observed already on a single ferromagnet/normal metal interface. The interface resistance is predicted to exhibit prominent features whenever the frequency of spin precession in the applied field becomes equal to the frequency of the driving current. Using these features, materialspecific gfactors of electrons in normal metals can be measured with less effort, albeit also with less precision.
 [87] arXiv:2406.13900 [pdf, html, other]

Title: Anomalous Fermi pockets on Hund's metal surface of Sr2RuO4 induced by the correlationenhanced spinorbit couplingTakeshi Kondo, Masayuki Ochi, Shuntaro Akebi, Yuyang Dong, Haruka Taniguchi, Yoshiteru Maeno, Shik ShinJournalref: Phys. Rev. B 109, L241107 (2024)Subjects: Strongly Correlated Electrons (condmat.strel); Materials Science (condmat.mtrlsci); Superconductivity (condmat.suprcon)
The electronic structure of the topmost layer in Sr2RuO4 in the close vicinity of the Fermi level is investigated by angleresolved photoemission spectroscopy (ARPES) with a 7eV laser. We find that the spinorbit coupling (SOC) predicted as 100 meV by the density functional theory (DFT) calculations is enormously enhanced in a real material up to 250 meV, even more than that of bulk state (200 meV), by the electroncorrelation effect increased by the octahedral rotation in the crystal structure. This causes the formation of highly orbitalmixing small Fermi pockets and reasonably explains why the orbitalselective Mott transition (OSMT) is not realized in perovskite oxides with crystal distortion. Interestingly, Hund's metal feature allows the quasiparticle generation only near EF, restricting the spectral gap opening derived by band hybridization within an extremely small binding energy (< 10 meV). Furthermore, it causes coherentincoherent crossover, making the Fermi pockets disappear at elevated temperatures. The anomalous Fermi pockets are characterized by the dichotomy of the orbitalisolating Hund's coupling and the orbitalmixing SOC, which is key to understanding the nature of Sr2RuO4.
 [88] arXiv:2406.13932 [pdf, html, other]

Title: Microscopic theory of magnetoresistance in ferromagnetic materialsComments: 6 pages, 4 figuresSubjects: Mesoscale and Nanoscale Physics (condmat.meshall)
The magnetoresistance (MR) effect, which stems from the spinexchange coupling between local moments and itinerant electrons in magnetic materials, is a challenging manybody and openquantum problem. Here, we develop a comprehensive microscopic theory of MR from an openquantum system perspective. The theory not only predicts the magnetic field and temperature dependencies of MR which are related to spin relaxation time and spinexchange field but also obtains the universal cosinesquare law of anisotropic MR that microscopically elucidates diverse MR effects from the magnoninduced spin flip, anisotropic spin relaxation, and Hanle spin precession of itinerant electrons. Moreover, we reveal fruitful behaviors of the MR effect that enable the simple detection of the microscopic spinexchange coupling through an electrical approach. Our theory contributes to a deeper understanding of the fundamental physics underlying MR and provides insights for experiments involving magnetic materials.
 [89] arXiv:2406.13950 [pdf, html, other]

Title: Valley polarization in twisted altermagnetismComments: 5 pages, 5 figuresSubjects: Materials Science (condmat.mtrlsci)
The combination of altermagnetism, twistronics and valleytronics is of great significance for potential applications in advanced electronic devices. Twisted magnetic van der Waals bilayers have been identified as an ideal platform for altermagnetism of any type, such as $d$wave, $g$wave, and $i$wave, by choosing the constituent monolayer with specific symmetry [arXiv:2404.17146 (2024)]. Here, we propose a way for achieving valley polarization in twisted altermagnetism by applying outofplane external electric field. Since the outofplane electric field creates a layerdependent electrostatic potential, the valleys form different layers will stagger, producing valley polarization. We also demonstrate the effectiveness of our proposed way using the twisted tightbinding model. It is found that the applied electric field can also induce valley/spingapless semiconductor and half metal besides valley polarization. Based on firstprinciples calculations, our proposed way to achieve valley polarization can be verified in twisted bilayer VOBr and monolayer $\mathrm{Ca(CoN)_2}$ as a special twisted altermagnet. These findings provide new opportunities for innovative spintronics, twistronics and valleytronics applications.
 [90] arXiv:2406.13953 [pdf, html, other]

Title: Peculiar corner states in magnetic fractalsComments: 5 figuresSubjects: Mesoscale and Nanoscale Physics (condmat.meshall)
Topological excitations in periodic magnetic crystals have received significant recent attention. However, it is an open question on their fate once the lattice periodicity is broken. In this work, we theoretically study the topological properties embedded in the collective dynamics of magnetic texture array arranged into a Sierpiński carpet structure with effective Hausdorff dimensionality $d_{f}=1.893$. By evaluating the quantized realspace quadrupole moment, we obtain the phase diagram supporting peculiar corner states that are absent in conventional square lattices. We identify three different higherorder topological states, i.e., outer corner state, type I and type II inner corner states. We further show that all these corner states are topologically protected and are robust against moderate disorder. Full micromagnetic simulations are performed to verify theoretical predictions with good agreement. Our results pave the way to investigating topological phases of magnetic texture based fractals and bridging the gap between magnetic topology and fractality.
 [91] arXiv:2406.13965 [pdf, html, other]

Title: Quantum analog to flapping of flags: interface instability for coflow binary superfluidsComments: 19 pages, 7 figuresSubjects: Quantum Gases (condmat.quantgas); General Relativity and Quantum Cosmology (grqc); High Energy Physics  Theory (hepth)
We study the interface dynamics in immiscible binary superfluids using its holographic description, which naturally consists of an inviscid superfluid component and a viscous normal fluid component. We give the first theoretical realization of interface instability for two superfluid components moving with identical velocity, providing a quantum analog to the flapping of flags that is common in daily life. This behavior is in sharp contrast to the one from GrossPitaevskii equation for which no such coflow instability develops in an isolated uniform system because of Galilean invariance. The real time evolution triggered by the dynamical instability exhibits intricate nonlinear patterns leading to quantum turbulence reminiscent of the quantum KelvinHelmholtz instability. Moreover, we show that such interface dynamics is essentially different from the Landau instability for which the frictionless flow becomes thermodynamically unstable above a critical superfluid velocity. Our study uncovers the rich interface dynamics of quantum fluids and the emergence of complex flow phenomena.
 [92] arXiv:2406.13978 [pdf, html, other]

Title: Topological Solitons in Squareroot Graphene Nanoribbons Controlled by Electric FieldsHaiyue Huang (1), Mamun Sarker (2), Percy Zahl (3), C. Stephen Hellberg (4), Jeremy Levy (5), Ioannis Petrides (1), Alexander Sinitskii (2), Prineha Narang (1,6) ((1) Division of Physical Sciences, College of Letters and Science, University of California, Los Angeles, California, USA (2) Department of Chemistry, University of Nebraska, Lincoln, Nebraska, USA (3) Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York, USA (4) U.S. Naval Research Laboratory, Washington, District of Columbia, USA (5) Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania, USA (6) Department of Electrical and Computer Engineering, University of California, Los Angeles, California, USA)Subjects: Mesoscale and Nanoscale Physics (condmat.meshall); Materials Science (condmat.mtrlsci); Computational Physics (physics.compph); Quantum Physics (quantph)
Graphene nanoribbons (GNRs) are unique quasionedimensional (1D) materials that have garnered a lot of research interest in the field of topological insulators. While the topological phases exhibited by GNRs are primarily governed by their chemical structures, the ability to externally control these phases is crucial for their potential utilization in quantum electronics and spintronics. Here we propose a class of GNRs featured by mirror symmetry and four zigzag segments in a unit cell that has unique topological properties induced and controlled by an externally applied electric field. Their band structures manifest two finite gaps which support topological solitons, as described by an effective squareroot model. To demonstrate the experimental feasibility, we design and synthesize a representative partially zigzag chevrontype GNR (pzcGNR) with the desired zigzag segments using a bottomup approach. Firstprinciples calculations on pzcGNR reveal band inversions at the two finite gaps by switching the direction of the electric field, which is in accordance with predictions from the squareroot Hamiltonian. We show different topological phases can be achieved by controlling the direction of the field and the chemical potential of the system in squareroot GNRs. Consequently, upon adding a stepfunction electric field, solitons states can be generated at the domain wall. We discuss the properties of two types of soliton states, depending on whether the terminating commensurate unit cell is mirror symmetric.
 [93] arXiv:2406.13981 [pdf, other]

Title: Electronic SelfOrganization in the \beta Pyrochlore Oxide CsW2O6Comments: 19 pages, 22 figuresSubjects: Materials Science (condmat.mtrlsci)
In this review, I present the electronic properties of the betapyrochlore oxide CsW2O6 and other related materials. At 215 K, CsW2O6 exhibits an electronic phase transition to a nonmagnetic insulating state, which exhibits a complex selforganization of 5d electrons. In this phase transition, various factors, such as geometrical frustration of the pyrochlore structure, moderately strong electron correlation, JahnTellerlike distortion, phase transition to the insulating state, and formation of chemical bonds in solids, which are powerful driving forces for achieving a wide variety of electronic properties in transition metal oxides, play important roles. In CsW2O6, the interplay of these factors has led to the emergence of an electronic phase transition that preserves the cubic symmetry, threedimensional nesting of Fermi surfaces, a possible charge order with a fractional valence satisfying the Anderson condition, and an equilateraltriangular trimer formation by a threecenteredtwoelectron bond. In addition to the introduction of these unique features of CsW2O6, each of them has been compared to those of other materials to provide an overview of the electronic properties of a wide variety of related materials, which can contribute to a complete understanding of the vast and infinite electronic phenomena in transition metal oxides.
 [94] arXiv:2406.14016 [pdf, other]

Title: Contribution of Andreev reflection to the mobility of surface state electrons on superfluid $^3$HeBComments: 21 pages, 5 figuresJournalref: J. Low Temp. Phys. (2024)Subjects: Other Condensed Matter (condmat.other); Mesoscale and Nanoscale Physics (condmat.meshall)
The mobility of the Wigner solid on the superfluid $^3$He is determined by the momentum transfer from the scattered $^3$He quasiparticles at the free surface. The scattering process of the quasiparticles is classified into the normal reflection and the Andreev retroreflection. Since the quasiparticles nearly conserve the momentum in the process of the Andreev retroreflection at the free surface, the Andreev reflected quasiparticles do not produce a resistive force to the Wigner solid. In this report, we have analytically calculated the contribution of the Andreev retroreflection to the mobility of the Wigner solid on superfluid $^3$HeB by employing a realistic model order parameter with the free surface. The Andreev retroreflection is lacked for quasiparticles with energy above the bulk energy gap under the model order parameter. Then, the Andreev retroreflection does not contribute to a rise in the mobility of the Wigner solid on the superfluid $^3$HeB. The present model calculation is in good agreement with the previous experimental observation. We have also discussed the Andreev retroreflection under a selfconsistently calculated order parameter.
 [95] arXiv:2406.14025 [pdf, other]

Title: Direct Observation of Dendrites Nucleation in Li Metal Battery by Machine Learning Accelerated Molecular Simulations under Realistic Electrochemical ConditionsTaiping Hu, Haichao Huang, Guobing Zhou, Xinyan Wang, Zheng Cheng, Fangjia Fu, Xiaoxu Wang, Fuzhi Dai, Kuang Yu, Shenzhen XuSubjects: Materials Science (condmat.mtrlsci)
Uncontrollable dendrites growth during electrochemical cycles leads to low Coulombic efficiency and critical safety issues in Li metal batteries. Hence, a comprehensive understanding of the dendrite formation mechanism is essential for further enhancing the performance of Li metal batteries. Machine learning accelerated molecular dynamics (MD) simulations can provide atomicscale resolution for various key processes at an abinitio level accuracy. However, traditional MD simulation tools hardly capture Li electrochemical depositions, due to lack of an electrochemical constant potential (ConstP) condition. In this work, we propose a ConstP approach that combines a machine learning force field with the charge equilibration method to reveal the dynamic process of Li dendrites nucleation at Li metal anode surfaces. Our results show that both dead Li cluster formation and inhomogeneous Li electrodepositions can induce Li dendrites nucleation. We further reveal that the local aggregation of Li atoms in amorphous inorganic components of solid electrolyte interphase is the key factor triggering the nucleation process. Overall, our simulations provide microscopic insights for Li dendrites formations in Li metal anodes. More importantly, we present an efficient and accurate simulation method for modeling realistic ConstP conditions, which holds considerable potential for broader applications in modeling of complex electrochemical interfaces.
 [96] arXiv:2406.14029 [pdf, html, other]

Title: Diraclike fermions anomalous magnetotransport in a spinpolarized oxide twodimensional electron systemYu Chen, Maria D'Antuono, Mattia Trama, Daniele Preziosi, Benoit Jouault, Frédéric Teppe, Christophe Consejo, Carmine A. Perroni, Roberta Citro, Daniela Stornaiuolo, Marco SalluzzoSubjects: Mesoscale and Nanoscale Physics (condmat.meshall); Strongly Correlated Electrons (condmat.strel)
In twodimensional electron systems (2DES) the breaking of the inversion, timereversal and bulk crystalfield symmetries is interlaced with the effects of spinorbit coupling (SOC) triggering exotic quantum phenomena. Here, we used epitaxial engineering to design and realize a 2DES characterized simultaneously by ferromagnetic order, large Rashba SOC and hexagonal band warping at the (111) interfaces between LaAlO$_{3}$, EuTiO$_{3}$ and SrTiO$_{3}$ insulators. The 2DES displays anomalous quantum corrections to the magnetoconductance driven by the timereversalsymmetry breaking occurring below the magnetic transition temperature. The results are explained by the emergence of a nontrivial Berry phase and competing weak antilocalization / weak localization backscattering of Diraclike fermions, mimicking the phenomenology of gapped topological insulators. These findings open perspectives for the engineering of novel spinpolarized functional 2DES holding promises in spinorbitronics and topological electronics.
 [97] arXiv:2406.14030 [pdf, html, other]

Title: The inviscid fixed point of the multidimensional BurgersKPZ equationComments: 17 pages, 5 figuresSubjects: Statistical Mechanics (condmat.statmech); Fluid Dynamics (physics.fludyn)
A new scaling regime characterized by a $z=1$ dynamical critical exponent has been reported in several numerical simulations of the onedimensional KardarParisiZhang and noisy Burgers equations. This scaling was found to emerge in the tensionless limit for the interface and in the inviscid limit for the fluid. Based on functional renormalization group, the origin of this scaling has been elucidated. It was shown to be controlled by a yet unpredicted fixed point of the onedimensional BurgersKPZ equation, termed inviscid Burgers fixed point. The associated universal properties, including the scaling function, were calculated. Here, we generalize this analysis to the multidimensional BurgersKPZ equation. We show that the inviscidBurgers fixed point exists in all dimensions $d$, and that it controls the large momentum behavior of the correlation functions in the inviscid limit. It turns out that it yields in all $d$ the same superuniversal value $z=1$ for the dynamical exponent.
 [98] arXiv:2406.14042 [pdf, html, other]

Title: Synthetic spinorbit coupling for the multispin models in optical latticesComments: 8 pages, 6 figuresSubjects: Quantum Gases (condmat.quantgas)
The essential role of synthetic spinorbit coupling in discovering new topological matter phases with cold atoms is widely acknowledged. However, the engineering of spinorbit coupling remains unclear for arbitraryspin models due to the complexity of spin matrices. In this work, we develop a more general but relatively straightforward method to achieve spinorbit coupling for multispin models. Our approach hinges on controlling the coupling between distinct pseudospins through two intermediary states, resulting in tunneling with spin flips that have directiondependent strength. The engineered spinorbit coupling can facilitate topological phase transitions with Chern numbers over 1, a unique characteristic of multispin models compared to spin1/2 models. By utilizing existing cold atom techniques, our proposed method provides an ideal platform for investigating topological properties related to large Chern numbers.
 [99] arXiv:2406.14049 [pdf, html, other]

Title: Emergent Universal Drag Law in a Model of SuperflowComments: 6+2 pages, 3+2 figures, 1 tableSubjects: Quantum Gases (condmat.quantgas); Fluid Dynamics (physics.fludyn)
Despite the fundamentally different dissipation mechanisms, many laws and phenomena of classical turbulence equivalently manifest in quantum turbulence. The Reynolds law of dynamical similarity states that two objects of same geometry across different length scales are hydrodynamically equivalent under the same Reynolds number, leading to a universal drag coefficient law. In this work we confirm the existence of a universal drag law in a superfluid wake, facilitated by the nucleation of quantized vortices. We numerically study superfluid flow across a range of Reynolds numbers for the paradigmatic classical hardwall and the Gaussian obstacle, popular in experimental quantum hydrodynamics. In addition, we provide a feasible method for measuring superfluid drag forces in an experimental environment using control volumes.
 [100] arXiv:2406.14070 [pdf, other]

Title: Electronelectron attraction via Coulomb correlations and possible superconductivity in a 1D electron liquid on a rigid neutralizing backgroundComments: 9 pages, 5 figuresSubjects: Superconductivity (condmat.suprcon)
Conditions at which a quasionedimensional (1D) electron system can be considered as a quantum liquid of impenetrable charged particles are theoretically analyzed. In the presence of an inert, neutralizing background, a motion of impenetrable electrons is shown to expose a positive charge, resulting in an effective mutual attraction of infinite range. As a result, all electrons are involved in the longrange pairing. A model of spinless fermions with infinitesimal attraction of infinite range is proposed to describe the excitation spectrum and the superconducting gap in lowdensity 1D electron channels. In contrast with the conventional theory, the energy gap does not contain exponentially small factors. It depends mostly on the Coulombic parameters of the system, which guides practical aspects of hightemperature superconductivity.
 [101] arXiv:2406.14079 [pdf, other]

Title: NanoPatterned PtBased Metallic Glass Electrocatalysts with InSitu Copper Oxide Foam for Enhanced Hydrogen EvolutionFeiFan Cai, Baran Sarac, Adnan Akman, Juan J. Londoño, Selin Gümrükcü, Lukas Schweiger, Martin Hantusch, Jan Schroers, Andreas Blatter, Annett Gebert, Florian Spieckermann, Jürgen EckertComments: 28 pages, 9 figures (including supplementary information)Subjects: Materials Science (condmat.mtrlsci); Chemical Physics (physics.chemph)
Hydrogen is a promising energy carrier for replacing fossil fuels, and hydrogen production via hydrogen evolution reaction (HER) is an environmentally friendly option if electrocatalysts with low overpotentials and longterm stability are used. In this work, the electrocatalytic performance of $\mathrm{Pt_{57.5}Cu_{14.7}Ni_{5.3}P_{22.5}}$ bulk metallic glass (BMG) with flat, micropatterned, and nanopatterned surfaces for HER in 0.5 M H2SO4 is studied. The nanopatterned PtBMG demonstrates outstanding longterm stability and selfimproving behavior with a final overpotential of 150 mV and a Tafel slope of 42 $\mathrm{mV dec^{1}}$ after 1000 linear sweep voltammetry (LSV) cycles, which is respectively 42% and 37% lower than in the first LSV cycle. Xray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES) indicate the formation of a layer of CuO/Cu2O foam deposited on top of the nanopatterned surface during the stability test of 1000 LSV cycles. A threestep process is proposed to explain the formation of CuxO foam via dynamic hydrogen bubble templating (DHBT) electrodeposition from Cu dissolution of the PtBMG without using copper salt. This work provides a method to create CuxO foams that could be used for various applications. Moreover, nanopatterned BMGs with DHBT deposition offer a feasible strategy to synthesize metal or metaloxide foams.
 [102] arXiv:2406.14151 [pdf, html, other]

Title: Automated detection and mapping of crystal tilt using thermal diffuse scattering in transmission electron microscopyMauricio Cattaneo, Knut MüllerCaspary, Juri Barthel, Katherine E. Mac Arthur, Nicolas Gauquelin, Marta LipinskaChwalek, Johan Verbeeck, Leslie J. Allen, Rafal E. DuninBorkowskiSubjects: Materials Science (condmat.mtrlsci)
Quantitative interpretation of transmission electron microscopy (TEM) data of crystalline specimens often requires the accurate knowledge of the local crystal orientation. A method is presented which exploits momentumresolved scanning TEM (STEM) data to determine the local mistilt from a major zone axis. It is based on a geometric analysis of Kikuchi bands within a single diffraction pattern, yielding the centre of the Laue circle. Whereas the approach is not limited to convergent illumination, it is here developed using unitcell averaged diffraction patterns corresponding to highresolution STEM settings. In simulation studies, an accuracy of approximately 0.1mrad is found. The method is implemented in automated software and applied to crystallographic tilt and inplane rotation mapping in two experimental cases. In particular, orientation maps of highMn steel and an epitaxially grown La$_{\text{0.7}}$Sr$_{\text{0.3}}$MnO$_{\text{3}}$SrTiO$_{\text{3}}$ interface are presented. The results confirm the estimates of the simulation study and indicate that tilt mapping can be performed consistently over a wide field of view with diameters well above 100nm at unit cell real space sampling.
 [103] arXiv:2406.14158 [pdf, html, other]

Title: Quantum vortices in fermionic superfluids: from ultracold atoms to neutron starsSubjects: Quantum Gases (condmat.quantgas); High Energy Astrophysical Phenomena (astroph.HE); Superconductivity (condmat.suprcon); Nuclear Theory (nuclth)
Superfluid dilute neutron matter and ultracold gas, close to the unitary regime, exhibit several similarities. Therefore, to a certain extent, fermionic ultracold gases may serve as emulators of dilute neutron matter, which forms the inner crust of neutron stars and is not directly accessed experimentally. Quantum vortices are one of the most significant properties of neutron superfluid, essential for comprehending neutron stars' dynamics. The structure and dynamics of quantum vortices as a function of pairing correlations' strength are being investigated experimentally and theoretically in ultracold gases. Certain aspects of these studies are relevant to neutron stars. We provide an overview of the characteristics of quantum vortices in swavetype fermionic and electrically neutral superfluids. The main focus is on the dynamics of fermionic vortices and their intrinsic structure.
 [104] arXiv:2406.14188 [pdf, html, other]

Title: Anisptropic plasmons in threefold Hopf semimetalsComments: 7 pages, 5 figuresSubjects: Mesoscale and Nanoscale Physics (condmat.meshall)
Threefold Hopf semimetals are a novel type of topological semimetals that possess an internal anisotropy characterized by a dipolar structure of the Berry curvature and an isotropic energy band structure consisting of a Dirac cone and a flat band. In this study, we theoretically investigate the impact of internal anisotropy on plasmons in threefold Hopf semimetals using randomphase approximation. In contrast to the classical intuition that isotropy of the energy band dispersion leads to isotropic plasmons in the classical regime (i.e., in the wavelength limit), we find that plasmons in threefold Hopf semimetals exhibit notable anisotropy even in the longwavelength limit. We derive an explicit analytical form of the longwavelength plasmon frequency, and numerically demonstrate the validity of our results in a wide range of situations. Our work reveals that the anisotropy of longwavelength plasmons can reach 25%, making it experimentally observable.
 [105] arXiv:2406.14193 [pdf, html, other]

Title: Reentrant localisation transitions and anomalous spectral properties in offdiagonal quasiperiodic systemsComments: 21 pages, 15 figures, comments are welcomeSubjects: Disordered Systems and Neural Networks (condmat.disnn)
We investigate the localisation properties of quasiperiodic tightbinding chains with hopping terms modulated by the interpolating AubryAndréFibonacci (IAAF) function. This offdiagonal IAAF model allows for a smooth and controllable interpolation between two paradigmatic quasiperiodic models: the AubryAndré and the Fibonacci model. Our analysis shows that the spectrum of this model can be divided into three principal bands, namely, two molecular bands at the edge of the spectrum and one atomic band in the middle, for all values of the interpolating parameter. We reveal that the states in the molecular bands undergo multiple reentrant localisation transitions, a behaviour previously reported in the diagonal IAAF model. We link the emergence of these reentrant phenomena to symmetry points of the quasiperiodic modulation and, with that, explain the main ground state properties of the system. The atomic states in the middle band show no traces of localised phases and remain either extended or critical for any value of the interpolating parameter. Using a renormalisation group approach, adapted from the Fibonacci model, we explain the extended nature of the middle band. These findings expand our knowledge of phase transitions within quasiperiodic systems and highlight the interplay between extended, critical, and localised states.
 [106] arXiv:2406.14200 [pdf, html, other]

Title: Gaussian approximation of dynamic cavity equations for linearlycoupled stochastic dynamicsComments: 44 pages, 5 figures (including supplemental material)Subjects: Disordered Systems and Neural Networks (condmat.disnn); Statistical Mechanics (condmat.statmech); Data Analysis, Statistics and Probability (physics.dataan)
Stochastic dynamics on sparse graphs and disordered systems often lead to complex behaviors characterized by heterogeneity in time and spatial scales, slow relaxation, localization, and aging phenomena. The mathematical tools and approximation techniques required to analyze these complex systems are still under development, posing significant technical challenges and resulting in a reliance on numerical simulations. We introduce a novel computational framework for investigating the dynamics of sparse disordered systems with continuous degrees of freedom. Starting with a graphical model representation of the dynamic partition function for a system of linearlycoupled stochastic differential equations, we use dynamic cavity equations on locally treelike factor graphs to approximate the stochastic measure. Here, cavity marginals are identified with local functionals of singlesite trajectories. Our primary approximation involves a secondorder truncation of a smallcoupling expansion, leading to a Gaussian form for the cavity marginals. For linear dynamics with additive noise, this method yields a closed set of causal integrodifferential equations for cavity versions of onetime and twotime averages. These equations provide an exact dynamical description within the local treelike approximation, retrieving classical results for the spectral density of sparse random matrices. Global constraints, nonlinear forces, and statedependent noise terms can be addressed using a selfconsistent perturbative closure technique. The resulting equations resemble those of dynamical meanfield theory in the modecoupling approximation used for fullyconnected models. However, due to their cavity formulation, the present method can also be applied to ensembles of sparse random graphs and employed as a messagepassing algorithm on specific graph instances.
 [107] arXiv:2406.14209 [pdf, other]

Title: 2024 roadmap on 2D topological insulatorsBent Weber, Michael S Fuhrer, XianLei Sheng, Shengyuan A Yang, Ronny Thomale, Saquib Shamim, Laurens W Molenkamp, David Cobden, Dmytro Pesin, Harold J W Zandvliet, Pantelis Bampoulis, Ralph Claessen, Fabian R Menges, Johannes Gooth, Claudia Felser, Chandra Shekhar, Anton Tadich, Mengting Zhao, Mark T Edmonds, Junxiang Jia, Maciej Bieniek, Jukka I Väyrynen, Dimitrie Culcer, Bhaskaran Muralidharan, Muhammad NadeemSubjects: Mesoscale and Nanoscale Physics (condmat.meshall)
2D topological insulators promise novel approaches towards electronic, spintronic, and quantum device applications. This is owing to unique features of their electronic band structure, in which bulkboundary correspondences enforces the existence of 1D spinmomentum locked metallic edge states  both helical and chiral  surrounding an electrically insulating bulk. Forty years since the first discoveries of topological phases in condensed matter, the abstract concept of band topology has sprung into realization with several materials now available in which sizable bulk energy gaps  up to a few hundred meV  promise to enable topology for applications even at roomtemperature. Further, the possibility of combining 2D TIs in heterostructures with functional materials such as multiferroics, ferromagnets, and superconductors, vastly extends the range of applicability beyond their intrinsic properties. While 2D TIs remain a unique testbed for questions of fundamental condensed matter physics, proposals seek to control the topologically protected bulk or boundary states electrically, or even induce topological phase transitions to engender switching functionality. Induction of superconducting pairing in 2D TIs strives to realize nonAbelian quasiparticles, promising avenues towards faulttolerant topological quantum computing. This roadmap aims to present a status update of the field, reviewing recent advances and remaining challenges in theoretical understanding, materials synthesis, physical characterization and, ultimately, device perspectives.
 [108] arXiv:2406.14215 [pdf, html, other]

Title: Excitons in nonlinear optical responses: shift current in MoS$_2$ and GeS monolayersComments: 12 pages, 5 figuresSubjects: Mesoscale and Nanoscale Physics (condmat.meshall); Materials Science (condmat.mtrlsci)
It is wellknown that exciton effects are determinant to understand the optical absorption spectrum of lowdimensional materials. However, the role of excitons in nonlinear optical responses has been much less investigated at an experimental level. Additionally, computational methods to calculate nonlinear conductivities in real materials are still not widespread, particularly taking into account excitonic interactions. We present a methodology to calculate the excitonic secondorder optical responses in 2D materials relying on: (i) ab initio tightbinding Hamiltonians obtained by Wannier interpolation and (ii) the BetheSalpeter equation with effective electronhole interactions. Here, in particular, we explore the role of excitons in the shift current of monolayer materials. Focusing on MoS$_2$ and GeS monolayer systems, our results show that $2p$like excitons, which are dark in the linear response regime, yield a contribution to the photocurrent comparable to that of $1s$like excitons. Under radiation with intensity $\sim 10^{4} $W/cm$^2$, the excitonic theory predicts ingap photogalvanic currents of almost $\sim 10$ nA in sufficiently clean samples, which is typically one order of magnitude higher than the value predicted by independentparticle theory near the band edge.
 [109] arXiv:2406.14224 [pdf, html, other]

Title: Cellular Automata model for period$n$ synchronization: A new universality classSubjects: Statistical Mechanics (condmat.statmech)
There are few known universality classes of absorbing phase transitions in one dimension and most models fall in the wellknown directed percolation (DP) class. Synchronization is a transition to an absorbing state and this transition is often DP class. With local coupling, the transition is often to a fixed point state. Transitions to a periodic synchronized state are seldom observed. Recently a transition to a synchronized period3 state that is not in DP class is observed. We model it using a cellular automata model with states 1 to $n$. The rules are a) Each site in state $i$ changes to state $i+1$ for $i<n$ and 1 if $i=n$. b) After this update, it takes value of either neighbor unless it is in state 1. With these rules, we observe a transition to synchronization with critical exponents different from those of DP for $n>2$. For $n=2$, a different exponent is observed.
 [110] arXiv:2406.14242 [pdf, other]

Title: Magnetotransport and thermoelectric studies of antiperovskite semimetal: Mn3SnCComments: 8 Pages, 5 figuresJournalref: J. Phys.: Condens. Matter 36 375603 (2024)Subjects: Strongly Correlated Electrons (condmat.strel); Materials Science (condmat.mtrlsci)
We explore the magnetotransport and thermoelectric (Seebeck and Nernst coefficients) properties of Mn3SnC an antiperovskite magnetic Nodal line semimetal. Mn3SnC shows paramagnetic (PM) to concurrent antiferromagnetic (AFM)/ferromagnetic (FM) transition at 286 K. The electrical resistivity and Seebeck coefficient indicate the importance of electron magnon scattering in the concurrent AFM/FM regime. We observed a large positive magnetoresistance (MR) of 8.2 at 8 T field near magnetic transition, in the otherwise negative MR behaviour for low temperatures. The electrical resistivity and MR show a weak thermal hysteresis around the boundary of transition temperature and the width of hysteresis decreases as magnetic field increases. Interestingly the Hall and Seebeck coefficients change sign from positive to negative below the transition temperature, highlighting the different scattering for holes and electrons in this multiband system. The Seebeck and Nernst signal exhibit two sharp anomalies; one at the transition temperature and another at 50 K. The anomaly at magnetic transition in the Nernst signal disappear at 8 T magnetic field, owing to the reduction of magnetic fluctuation. A pseudogap near the Fermi level produces an upturn with a broad minimum in the Seebeck signal.
 [111] arXiv:2406.14248 [pdf, html, other]

Title: Starving Random WalksComments: 21 pages, 5 figures. Contribution to the book "The Mathematics of Movement: an Interdisciplinary Approach to Mutual Challenges in Animal Ecology and Cell Biology" edited by Luca Giuggioli and Philip MainiSubjects: Statistical Mechanics (condmat.statmech); Mathematical Physics (mathph)
In this chapter, we review recent results on the starving random walk (RW) problem, a minimal model for resourcelimited exploration. Initially, each lattice site contains a single food unit, which is consumed upon visitation by the RW. The RW starves whenever it has not found any food unit within the previous $\mathcal{S}$ steps. To address this problem, the key observable corresponds to the intervisit time $\tau_k$ defined as the time elapsed between the finding of the $k^\text{th}$ and the $(k+1)^\text{th}$ food unit. By characterizing the maximum $M_n$ of the intervisit times $\tau_0,\dots,\tau_{n1}$, we will see how to obtain the number $N_\mathcal{S}$ of food units collected at starvation, as well as the lifetime $T_\mathcal{S}$ of the starving RW.
 [112] arXiv:2406.14256 [pdf, html, other]

Title: Microscopic and stochastic simulations of chemically active dropletsSubjects: Soft Condensed Matter (condmat.soft); Statistical Mechanics (condmat.statmech); Biological Physics (physics.bioph)
Biomolecular condensates play a central role in the spatial organization of living matter. Their formation is now well understood as a form of liquidliquid phase separation that occurs very far from equilibrium. For instance, they can be modeled as active droplets, where the combination of molecular interactions and chemical reactions result in microphase separation. However, so far, models of chemically active droplets are spatially continuous and deterministic. Therefore, the relationship between the microscopic parameters of the models and some crucial properties of active droplets (such as their polydispersity, their shape anisotropy, or their typical lifetime) is yet to be established. In this work, we address this question computationally, using Brownian dynamics simulations of chemically active droplets: the building blocks are represented explicitly as particles that interact with attractive or repulsive interactions, depending on whether they are in a dropletforming state or not. Thanks to this microscopic and stochastic view of the problem, we reveal how driving the system away from equilibrium in a controlled way determines the fluctuations and dynamics of active emulsions.
 [113] arXiv:2406.14289 [pdf, other]

Title: Electrical switching of chirality in rhombohedral graphene Chern insulatorsJing Ding, Hanxiao Xiang, Jiannan Hua, Wenqiang Zhou, Naitian Liu, Le Zhang, Na Xin, Kenji Watanabe, Takashi Taniguchi, Wei Zhu, Shuigang XuComments: 21 pages, 4 figures in main textSubjects: Mesoscale and Nanoscale Physics (condmat.meshall); Materials Science (condmat.mtrlsci); Strongly Correlated Electrons (condmat.strel)
A Chern insulator hosts topologically protected chiral edge currents with quantized conductance characterized by its Chern number. Switching the chirality of the Chern insulator, namely, the direction of the edge current, is highly challenging due to topologically forbidden backscattering but is of considerable importance for the design of topological devices. Nevertheless, this can be achieved by reversing the sign of the Chern number through a topological phase transition. Here, we report electrically switchable chirality in rhombohedral heptalayer graphenebased Chern insulators. The surface flat band and giant Berry curvature in rhombohedral multilayer graphene provide a highly tunable platform for engineering the topological states. By introducing moire superlattices in rhombohedral heptalayer graphene, we observed a cascade of topological phase transitions at quarter electron filling of a moire band. The Chern number can be continuously tuned from 0, 1, 1 to 2 by electric fields, manifesting as a large anomalous Hall effect and following Streda's formula. Sign reversal and the anomalous Hall effect also occurred at noninteger fillings, suggesting the possibility of electrically tunable topological phase transitions within the regime of fractional Chern insulators. Our work establishes rhombohedral heptalayer graphene moire superlattices as a versatile platform for topological engineering. The realization of switchable chirality enhances the potential application of chiral edge currents in topological circuit interconnects.
 [114] arXiv:2406.14303 [pdf, html, other]

Title: NonHermitian topology of transport in Chern insulatorsComments: 9 pages, 8 figuresSubjects: Mesoscale and Nanoscale Physics (condmat.meshall)
It has recently been shown that signatures of nonHermitian topology can be realized in a conventional quantum Hall device connected to multiple current sources. These signatures manifest as robust currentvoltage characteristics, dictated by the presence of a nontrivial, nonHermitian topological invariant of the conductance matrix. Chiral edge states are believed to be responsible for this nonHermitian response, similar to how they lead to a quantized Hall conductivity in the presence of a single current source. Here, we go beyond this paradigm, showing that multiterminal conductance matrices can exhibit nonHermitian topological phase transitions that cannot be traced back to the presence and directionality of a boundarylocalized chiral mode. By performing quantum transport simulations in the quantum Hall regime of monolayer graphene, we find that when the chemical potential is swept across the zeroth Landau level, unavoidable device imperfections cause the appearance of an additional nonHermitian phase of the conductance matrix. This highlights graphene as an ideal platform for the study of nonHermitian topological phase transitions, and is a first step towards exploring how the geometry of quantum devices can be harnessed to produce robust, topologicallyprotected transport characteristics.
 [115] arXiv:2406.14306 [pdf, html, other]

Title: Efficient parameterization of transferable Atomic Cluster Expansion for waterSubjects: Materials Science (condmat.mtrlsci)
We present a highly accurate and transferable parameterization of water using the atomic cluster expansion (ACE). To efficiently sample liquid water, we propose a novel approach that involves sampling static calculations of various ice phases and utilizing the active learning (AL) feature of ACEbased Doptimality algorithm to select relevant liquid water configurations, bypassing computationally intensive abinitio molecular dynamics (AIMD) simulations. Our results demonstrate that the ACE descriptors enable a potential initiallyfitted solely on ice structures which is later upfitted with few configurations of liquid, identified with active learning to provide an excellent description of liquid water. The developed potential exhibits remarkable agreement with firstprinciples reference, accurately capturing various properties of liquid water, including structural characteristics such as pair correlation functions, covalent bonding profiles, and hydrogen bonding profiles, as well as dynamic properties like the vibrational density of states, diffusion coefficient and thermodynamic properties such as the melting point of the ice Ih. Our research introduces a new and efficient sampling technique for machine learning potentials in water simulations, while also presenting a transferable interatomic potential for water that reveals the accuracy of first principles reference. This advancement not only enhances our understanding the relationship between ice and liquid water at the atomic level, but also opens up new avenues for studying complex aqueous systems.
 [116] arXiv:2406.14316 [pdf, html, other]

Title: Cluster Formation induced by local dielectric saturation in Restricted Primitive Model ElectrolytesSubjects: Soft Condensed Matter (condmat.soft); Statistical Mechanics (condmat.statmech)
Experiments using the Surface Force Apparatus (SFA) have found anomalously long ranged chargecharge underscreening in concentrated salt solutions. Meanwhile, theory and simulations have suggested ion clustering to be the possible origin of this behaviour. The popular Restricted Primitive Model of electrolyte solutions, in which the solvent is represented by a uniform relative dielectric constant, $\varepsilon_r$, is unable to resolve the anomalous underscreening seen in experiments. In this work, we modify the Restricted Primitive Model to account for local dielectric saturation within the ion hydration shell. The dielectric constant in our model locally decreases from the bulk value to a lower saturated value at the ionic surface. The parameters for the model are deduced so that typical salt solubilities are obtained. Our simulations for both bulk and slit geometries show that our model displays strong cluster formation and these give rise to longranged interactions between charged surfaces at distances similar to what has been observed in SFA measurements. An electrolyte model wherein the dielectric constant remains uniform does not display similar clusters, even with $\varepsilon_r$ equal to the saturated value at ion contact. Hence, the observed behaviours are not simply due to an enhanced Coulomb interaction.
 [117] arXiv:2406.14323 [pdf, html, other]

Title: Anisotropy of YuShibaRusinov states in NbSe$_2$Comments: 5+5 pages, 3+4 figuresSubjects: Superconductivity (condmat.suprcon)
The spatial structure of ingap YuShibaRusinov (YSR) bound states induced by a magnetic impurity in a superconductor is the essential ingredient for the possibility of engineering collective impurity states. Recently, a saddlepoint approximation [Phys. Rev. B 105, 144503] revealed how the spatial form of a YSR state is controlled by an anisotropic exponential decay length, and an anisotropic prefactor, which depends on the Fermi velocity and Fermisurface curvature. Here we analyze STM data on YSR states in NbSe$_2$, focusing on a key issue that the exponential decay length predicted theoretically from the small superconducting gap is much larger than the observed extent of YSR states. We confirm that the exponential decay can be neglected in the analysis of the anisotropy. Instead, we extract the anisotropic prefactor directly from the data, matching it to the theoretical prediction, and we establish that the theoretical expression for the prefactor alone captures the characteristic flowerlike shape of the YSR state. Surprisingly, we find that up to linear order in the superconducting gap the anisotropic prefactor that determines the shape of YSR states is the same as the anisotropic response to the impurity in the underlying normal metal. Our work points out the correct way to analyze STM data on impurities in smallgap superconductors, and reveals the importance of the normal band structure's curvature and Fermi velocity in designing multiimpurity ingap states in superconductors.
 [118] arXiv:2406.14327 [pdf, html, other]

Title: Application of Haldane's statistical correlation theory in classical systemsSubjects: Statistical Mechanics (condmat.statmech); Mathematical Physics (mathph); Data Analysis, Statistics and Probability (physics.dataan); Quantum Physics (quantph)
This letter investigates the application of Haldane's statistical correlation theory in classical systems. A modified statistical correlation theory has been proposed by including nonlinearity into the original theory of Haldane. It is shown that indistinguishability can be introduced as a form of external statistical correlation into distinguishable systems. It is proved that this modified statistical correlation theory can be used to derive classical fractional exclusion statistics (CFES) using maximum entropy methods for a selfcorrelating system. An extended nonlinear correlation model based on power series expansion is also proposed, which can produce various intermediate statistical models.
 [119] arXiv:2406.14354 [pdf, html, other]

Title: Quantum anomalous, quantum spin, and quantum valley Hall effects in pentalayer rhombohedral grapheneComments: 11 pages, 7 figuresSubjects: Strongly Correlated Electrons (condmat.strel); Mesoscale and Nanoscale Physics (condmat.meshall)
Recent experiments in pentalayer rhombohedral graphene moiré superlattice have observed the quantum anomalous Hall effect at the moiré filling factor $\nu=1$ and various fractions. These effects result from a flat Chern band induced by electronelectron interactions. In this Letter, we show that the manybody effects at $\nu=2$ give rise to the quantum spin Hall and quantum valley Hall states, even without spinorbit couplings or valleydependent potentials, in addition to the quantum anomalous Hall state. These three topological states can be selectively induced by applying and tilting a magnetic field. Furthermore, we demonstrate that at $\nu=3$ and $4$, a combination of the Wignerlike crystal state and topological states can be the ground state. Consequently, the relation between states at the filling factor $\nu$ and its particlehole counterpart $4\nu$ breaks down, which contrasts with the conventional quantum Hall effect in graphene.
 [120] arXiv:2406.14381 [pdf, other]

Title: Nonthermal Magnetic Deicing Using TwoDimensional Chromium TellurideChinmayee Chowde Gowda, Alexey Kartsev, Nishant Tiwari, Safronov A.A, Prafull Pandey, Ajit K. Roy, Pulickel M. Ajayan, Douglas S. Galvao, Chandra Sekhar TiwarySubjects: Materials Science (condmat.mtrlsci)
Twodimensional (2D) chromium telluride Cr2Te3 exhibits strong ferromagnetic ordering with high coercivity at low temperatures and paramagnetic behaviour when approaching room temperature. The spin states of monolayer Cr2Te3 show ferromagnetic ordering in the ground state, and insitu Raman analysis shows reversible structure transformation and hence a ferromagnetic to paramagnetic transition during lowtemperature heating cycles (0  25 °C). The magnetic phase transition near room temperature in the 2D Cr2Te3 prompted the exploration of these layered materials for energy application. We demonstrate that the lowtemperature ferromagnetic behavior can be used to magnetically deice material surfaces using an external magnetic source, avoiding the use of harsh chemicals and high temperatures. The hydrophobic nature and dipole interactions of H2O molecules with the surface of the 2D Cr2Te3 coating aid in the condensation of ice droplets formed on the surface. Firstprinciples calculations also confirm the observed crystal structure, surface interaction, and magnetic properties of 2D Cr2Te3.
 [121] arXiv:2406.14383 [pdf, html, other]

Title: Molecular simulations of crazes in glassy polymers under cyclic loadingSubjects: Soft Condensed Matter (condmat.soft)
We study with molecular dynamics simulations of a generic beadspring model the cyclic crazing behaviour of glassy polymers. The aim is to elucidate the mechanical response of sole fibrillated craze matter as well as its interaction with bulk material. The macroscopic stress response exhibits a hysteresis, which is quasi stationary after the first cycle and largely independent of deformation rate and temperature. It results from a complex interplay between constraints imposed by the entanglement network, pore space and pore space closure. Once the craze fibrils are oriented, stretching of the covalent backbone bonds leads to a rapid stress increase. In the initial stages of unloading, a loss in entanglement contact yields a quick stress relaxation in the backbone. During unloading, the craze fibrils undergo a rigid body (i.e.\ stressfree) folding motion due to the surrounding pore space, so that the structural behaviour of craze fibrils during unloading is most accurately described as stringlike. The reloading response depends significantly on the degree of pore space closure and the enforced intermolecular interaction during unloading. It ranges from a linear stress increase to a recavitation with a redrawing response. Compared to the bulk stiffness, the craze stiffness is two orders of magnitude lower and as a result, the macro response of coexisting craze and bulk matter is governed by the sole fibrillated craze matter.
 [122] arXiv:2406.14400 [pdf, html, other]

Title: Magnetic anisotropy of $4f$ atoms on a WSe$_2$ monolayer: a DFT+U studySubjects: Mesoscale and Nanoscale Physics (condmat.meshall); Materials Science (condmat.mtrlsci)
Inspired by recent advancements in the field of singleatom magnets, particularly those involving rareearth (RE) elements, we present a theoretical exploration employing DFT+$U$ calculations to investigate the magnetic properties of selected $4f$ atoms, specifically Eu, Gd and Ho, on a monolayer of the transitionmetal dichalcogenide WSe$_2$ in the 1Hphase. This study comparatively examines RE with diverse $4f$ orbital fillings and valence chemistry, aiming to understand how different coverage densities atop WSe$_2$ affect the magnetocrystalline anisotropy. We observe that RE elements lacking $5d$ occupation in the atomic limit exhibit larger magnetic anisotropy energies at high densities, while those with outer $5d$ electrons show larger anisotropies in dilute configurations. Additionally, even halffilled $4f$ shell atoms with small orbital magnetic moments can generate substantial energy barriers for magnetization rotation due to prominent orbital hybridizations with WSe$_2$. Open $4f$ shell atoms further enhance anisotropy barriers through spinorbit coupling effects. This aspect is crucial for the experimental realization of stable magnetic information units.
 [123] arXiv:2406.14417 [pdf, other]

Title: Electrical switching of Isingsuperconducting nonreciprocity for quantum neuronal transistorJunlin Xiong, Jiao Xie, Bin Cheng, Yudi Dai, Xinyu Cui, Lizheng Wang, Zenglin Liu, Ji Zhou, Naizhou Wang, Xianghan Xu, Xianhui Chen, SangWook Cheong, ShiJun Liang, Feng MiaoJournalref: Nature Communications 15, 4953 (2024)Subjects: Mesoscale and Nanoscale Physics (condmat.meshall)
Nonreciprocal quantum transport effect is mainly governed by the symmetry breaking of the material systems and is gaining extensive attention in condensed matter physics. Realizing electrical switching of the polarity of the nonreciprocal transport without external magnetic field is essential to the development of nonreciprocal quantum devices. However, electrical switching of superconducting nonreciprocity remains yet to be achieved. Here, we report the observation of fieldfree electrical switching of nonreciprocal Ising superconductivity in Fe3GeTe2/NbSe2 van der Waals (vdW) heterostructure. By taking advantage of this electrically switchable superconducting nonreciprocity, we demonstrate a proofofconcept nonreciprocal quantum neuronal transistor, which allows for implementing the XOR logic gate and faithfully emulating biological functionality of a cortical neuron in the brain. Our work provides a promising pathway to realize fieldfree and electrically switchable nonreciprocity of quantum transport and demonstrate its potential in exploring neuromorphic quantum devices with both functionality and performance beyond the traditional devices.
 [124] arXiv:2406.14435 [pdf, html, other]

Title: The superconducting clockcircuit: Improving the coherence of Josephson radiation beyond the thermodynamic uncertainty relationComments: 16 pages, 4 figures, Submission to SciPostSubjects: Mesoscale and Nanoscale Physics (condmat.meshall); Statistical Mechanics (condmat.statmech)
In the field of superconducting electronics, the onchip generation of AC radiation is essential for further advancements. Although a Josephson junction can emit AC radiation from a purely DC voltage bias, the coherence of this radiation is significantly limited by JohnsonNyquist noise. We relate this limitation to the thermodynamic uncertainty relation (TUR) in the field of stochastic thermodynamics. Recent findings indicate that the thermodynamic uncertainty relation can be broken by a classical pendulum clock. We demonstrate how the violation of the TUR can be used as a design principle for radiation sources by showing that a superconducting clock circuit emits coherent AC radiation from a DC bias.
 [125] arXiv:2406.14443 [pdf, other]

Title: Thin Film Synthesis, Structural Analysis, and Magnetic Properties of Novel Ternary Transition Metal Nitride MnCoN2Sita Dugu, Rebecca W Smaha, Shaham Quadir, Andrew Treglia, Shaun ODonnell, Julia Martin, Sharad Mahatara, Glenn Teeter, Stephan Lany, James R Neilson, Sage R BauersSubjects: Materials Science (condmat.mtrlsci)
Recent highthroughput computational searches have predicted many novel ternary nitride compounds providing new opportunities for materials discovery in under explored phase spaces. Nevertheless, there are hardly any predictions and/or syntheses that incorporate only transition metals into new ternary nitrides. Here, we report on the synthesis, structure, and properties of MnCoN$_2$, a new ternary nitride material comprising only transition metals and N. We find that crystalline MnCoN$_2$ can be stabilized over its competing binaries, and over a tendency of this system to become amorphous, by controlling growth temperature within a narrow window slightly above ambient condition. We find that singlephase MnCoN$_2$ thin films form in a cationdisordered rocksalt crystal structure, which is supported by abinitio calculations. Xray photoelectron spectroscopy analysis suggests that MnCoN$_2$ is sensitive to oxygen through various oxides and hydroxides binding to cobalt on the surface. Xray absorption spectroscopy is used to verify that Mn$^{3+}$ and Co$^{3+}$ cations exist in an octahedrallycoordinated environment, which is distinct from a combination of CoN and MnN binaries and in agreement with the rocksaltbased crystal structure prediction. Magnetic measurements suggest that MnCoN$_2$ has a canted antiferromagnetic ground state below 10 K. We extract a Weiss temperature of $\theta$ = 49.7 K, highlighting the antiferromagnetic correlations in MnCoN$_2$.
 [126] arXiv:2406.14465 [pdf, html, other]

Title: AC conductivity and magnetic dichroism of twodimensional antiferromagnetic Dirac semimetalsSubjects: Mesoscale and Nanoscale Physics (condmat.meshall); Materials Science (condmat.mtrlsci)
We investigate the magnetooptical properties of twodimensional nonsymmorphic Dirac semimetals in the presence of antiferromagnetic order. Using the Kubo formula, we calculate the conductivity tensor of twodimensional CuMnAs, a prototype antiferromagnetic Dirac material, as a function of light frequency. From the finitefrequency conductivity tensor, we derive the dynamic dielectric function and magnetic linear dichroism, demonstrating how they are influenced by the orientation of the N{é}el order parameter. Adjusting the N{é}el vector changes both the sign and amplitude of the system's magnetooptical response. We propose that magnetic linear dichroism spectroscopy is a powerful technique for determining the orientation of the N{é}el vector.
 [127] arXiv:2406.14505 [pdf, html, other]

Title: Dynamics of colloidal rods rotating in viscoelastic mediaSubjects: Soft Condensed Matter (condmat.soft)
We experimentally investigate the inplane rotational motion of ferromagnetic colloidal rods in viscoelastic media under a rotating magnetic field. Contrary to their rotation in a Newtonian fluid, in a viscoelastic fluid the rods continue to exhibit a net angular drift even for applied field frequencies which is an order of magnitude larger than the stepout frequency. Despite experimental evidence, previous studies failed to explain the observed behavior. This is due to the inherent assumption that the rods angular velocity beyond stepout follows same dependence on the applied field frequency as the Newtonian fluids. We demonstrated that the observed net rotation of rods after stepout originates from their interaction with the microstructural stressrelaxation processes within the viscoelastic fluid. Consequently, it exhibits a strong dependence on the rheological properties of the fluid. Our results are further supported by a minimal model which incorporates the memorymediated response of the viscoelastic fluid on their motion. Furthermore, we demonstrate, both experimentally and numerically, that the observed effect represents a generic feature of viscoelastic media and is expected to manifest for elongated probes in other complex surroundings such as biological assays and colloidal glasses.
 [128] arXiv:2406.14523 [pdf, html, other]

Title: Optical and Raman selection rules for oddparity clean superconductorsComments: 16 pages, 12 figuresJournalref: Phys. Rev. B 109, 245119 (2024)Subjects: Strongly Correlated Electrons (condmat.strel); Superconductivity (condmat.suprcon)
We derive selection rules in optical absorption and Raman scattering spectra, that can determine the parity of pairing order parameters under inversion symmetry in two classes of \emph{clean} superconductors: (i) chiral superconductors with strong spinorbit couplings, (ii) singlet superconductors with negligible spinorbit couplings. Experimentally, the inversion parity of pair wave functions can be determined by comparing the "optical gap" $\Delta_\text{op}$ in Raman and optical spectroscopy and the "thermodynamic gap" $2\Delta$ in specific heat measurements, and the selection rules apply when $\Delta_\text{op}>2\Delta$. We demonstrate the selection rules in superconductivity in models of (i) doped Weyl semimetals and (ii) doped graphene. Our derivation is based on the relation between pairing symmetry and fermion projective symmetry group of a superconductor. We further derive similar selection rules for twodimensional superconductors with 2fold rotational symmetry, and discuss how they apply to the superconducting state in magicangle twisted bilayer graphene.
 [129] arXiv:2406.14524 [pdf, html, other]

Title: HighTc superconductor candidates proposed by machine learningSubjects: Superconductivity (condmat.suprcon)
We cast the relation between chemical compositions of solidstate materials and their superconducting critical temperature (Tc) in terms of a statistical learning problem with reduced complexity. Training of queryaware similaritybased ridge regression models on experimental SuperCon data with (implicit) and without (ambient) high pressure entries achieves average Tc prediction errors of ~10 K for unseen outofsample materials. Subsequent utilization of the approach to scan ~153k materials in the Materials Project enables the ranking of candidates by Tc while taking into account thermodynamic stability and small band gap. Stable top three highTc candidate materials with large band gaps for implicit and ambient pressures are predicted to be Cs2Sn(H2N)6 (324 K), CsH5N2 (315K), Rb2Sn(H2N)6 (305 K), and H15IrBr3N5 (189 K), H12OsN5Cl3O (161 K), B10H13I (151 K), respectively. Stable top three highTc candidate materials with small band gaps for implicit and ambient pressures are predicted to be RbLiH12Se3N4 (255 K), CeH14Cl3O7 (246 K), Li(H3N)4 (234 K), and ReH30Ru2(NCl)10 (127 K), AlH18Ru(NF)6 (120 K), Sr(Li2P)2 (117 K), respectively.
New submissions for Friday, 21 June 2024 (showing 129 of 129 entries )
 [130] arXiv:2406.10597 (crosslist from quantph) [pdf, html, other]

Title: Onchip microwave coherent source with insitu control of the photon number distributionComments: 12 pages, 4 figuresSubjects: Quantum Physics (quantph); Other Condensed Matter (condmat.other); Superconductivity (condmat.suprcon); Applied Physics (physics.appph)
Coherent photon sources are key elements in different applications, ranging from quantum sensing to quantum computing. In the context of circuit quantum electrodynamics, there have been multiple proposals for potential coherent sources of photons, but a well established candidate is still missing. The possibility of designing and engineering superconducting circuits behaving like artificial atoms supports the realization of quantum optics protocols, including microwave photons generation. Here we propose and theoretically investigate a new design that allows a tunable photon injection directly onchip. The scheme is based on initiating a population inversion in a superconducting circuit that will act as the photon source of one or multiple target resonators. The key novelty of the proposed layout consists in replacing the usual capacitive link between the source and the target cavity with a tunable coupler, with the advantage of having ondemand control on the injected steadystate photons. We validate the dynamical control of the generated coherent states under the effect of an external flux threading the tunable coupler and discuss the possibility of employing this scheme also in the context of multiple bosonic reservoirs.
 [131] arXiv:2406.12895 (crosslist from qbio.NC) [pdf, html, other]

Title: Temporal Complexity of a HopfieldType Neural Model in Random and ScaleFree GraphsSubjects: Neurons and Cognition (qbio.NC); Disordered Systems and Neural Networks (condmat.disnn); Mathematical Physics (mathph); Numerical Analysis (math.NA); Adaptation and SelfOrganizing Systems (nlin.AO)
The Hopfield network model and its generalizations were introduced as a model of associative, or contentaddressable, memory. They were widely investigated both as a unsupervised learning method in artificial intelligence and as a model of biological neural dynamics in computational neuroscience. The complexity features of biological neural networks are attracting the interest of scientific community since the last two decades. More recently, concepts and tools borrowed from complex network theory were applied to artificial neural networks and learning, thus focusing on the topological aspects. However, the temporal structure is also a crucial property displayed by biological neural networks and investigated in the framework of systems displaying complex intermittency. The IntermittencyDriven Complexity (IDC) approach indeed focuses on the metastability of selforganized states, whose signature is a powerdecay in the interevent time distribution or a scaling behavior in the related eventdriven diffusion processes. The investigation of IDC in neural dynamics and its relationship with network topology is still in its early stages. In this work we present the preliminary results of a IDC analysis carried out on a bioinspired Hopfieldtype neural network comparing two different connectivities, i.e., scalefree vs. random network topology. We found that random networks can trigger complexity features similar to that of scalefree networks, even if with some differences and for different parameter values, in particular for different noise levels.
 [132] arXiv:2406.12916 (crosslist from cs.LG) [pdf, html, other]

Title: Opening the Black Box: predicting the trainability of deep neural networks with reconstruction entropyComments: 22 pages, 5 figures, 1 tableSubjects: Machine Learning (cs.LG); Disordered Systems and Neural Networks (condmat.disnn); High Energy Physics  Theory (hepth); Machine Learning (stat.ML)
An important challenge in machine learning is to predict the initial conditions under which a given neural network will be trainable. We present a method for predicting the trainable regime in parameter space for deep feedforward neural networks, based on reconstructing the input from subsequent activation layers via a cascade of singlelayer auxiliary networks. For both MNIST and CIFAR10, we show that a single epoch of training of the shallow cascade networks is sufficient to predict the trainability of the deep feedforward network, thereby providing a significant reduction in overall training time. We achieve this by computing the relative entropy between reconstructed images and the original inputs, and show that this probe of information loss is sensitive to the phase behaviour of the network. Our results provide a concrete link between the flow of information and the trainability of deep neural networks, further elucidating the role of criticality in these systems.
 [133] arXiv:2406.12939 (crosslist from quantph) [pdf, html, other]

Title: Measurement of ManyBody Quantum Correlations in Superconducting CircuitsComments: 12 pages, 4 figuresSubjects: Quantum Physics (quantph); Mesoscale and Nanoscale Physics (condmat.meshall); Quantum Gases (condmat.quantgas); Superconductivity (condmat.suprcon)
Recent advances in superconducting circuit technology have made the fabrication of large, customizable circuits routine. This has led to their application to areas beyond quantum information and, in particular, to their use as quantum simulators. A key challenge in this effort has been the identification of the quantum states realized by these circuits. Here, we propose a probe circuit capable of reading out manybody correlations in an analog quantum simulator. Our measurement scheme, designed for manyphoton states, exploits the nonlinearity of the Josephson junction to measure twopoint (and potentially higherorder) correlation functions of the superconducting phase operator. We demonstrate the capabilities of this design in the context of an LCladder with a quantum impurity. The proposed probe allows for the measurement of inherently quantum correlations, such as squeezing, and has the potential to significantly expand the scope of analog quantum simulations using superconducting circuits.
 [134] arXiv:2406.12974 (crosslist from hepth) [pdf, html, other]

Title: Bounding irrelevant operators in the 3d GrossNeveuYukawa CFTsComments: 13 pages, 4 figuresSubjects: High Energy Physics  Theory (hepth); Statistical Mechanics (condmat.statmech); Strongly Correlated Electrons (condmat.strel); High Energy Physics  Lattice (heplat)
We perform a numerical bootstrap study of scalar operators in the critical 3d GrossNeveuYukawa models, a family of conformal field theories containing N Majorana fermions in the fundamental representation of an O(N) global symmetry. We compute rigorous bounds on the scaling dimensions of the nexttolowest parityeven and parityodd singlet scalars at N = 2, 4, and 8. All of these dimensions have lower bounds greater than 3, implying that there are only two relevant singlet scalars and placing constraints on the RG flow structure of these theories.
 [135] arXiv:2406.12978 (crosslist from quantph) [pdf, other]

Title: Tensor networks for noninvertible symmetries in 3+1d and beyondComments: 72+1 pages, 11 (numbered) figures, 2 tablesSubjects: Quantum Physics (quantph); Strongly Correlated Electrons (condmat.strel); High Energy Physics  Theory (hepth)
Tensor networks provide a natural language for noninvertible symmetries in general Hamiltonian lattice models. We use ZXdiagrams, which are tensor network presentations of quantum circuits, to define a noninvertible operator implementing the Wegner duality in 3+1d lattice $\mathbb{Z}_2$ gauge theory. The noninvertible algebra, which mixes with lattice translations, can be efficiently computed using ZXcalculus. We further deform the $\mathbb{Z}_2$ gauge theory while preserving the duality and find a model with nine exactly degenerate ground states on a torus, consistent with the LiebSchultzMattistype constraint imposed by the symmetry. Finally, we provide a ZXdiagram presentation of the noninvertible duality operators (including noninvertible parity/reflection symmetries) of generalized Ising models based on graphs, encompassing the 1+1d Ising model, the threespin Ising model, the AshkinTeller model, and the 2+1d plaquette Ising model. The mixing (or lack thereof) with spatial symmetries is understood from a unifying perspective based on graph theory.
 [136] arXiv:2406.13026 (crosslist from quantph) [pdf, html, other]

Title: Polynomially restricted operator growth in dynamically integrable modelsComments: 5 pages 3 figuresSubjects: Quantum Physics (quantph); Statistical Mechanics (condmat.statmech)
We provide a framework to determine the upper bound to the complexity of a computing a given observable with respect to a Hamiltonian. By considering the Heisenberg evolution of the observable, we show that each Hamiltonian defines an equivalence relation, causing the operator space to be partitioned into equivalence classes. Any operator within a specific class never leaves its equivalence class during the evolution. We provide a method to determine the dimension of the equivalence classes and evaluate it for various models, such as the $ XY $ chain and Kitaev model on trees. Our findings reveal that the complexity of operator evolution in the $XY$ model grows from the edge to the bulk, which is physically manifested as suppressed relaxation of qubits near the boundary. Our methods are used to reveal several new cases of simulable quantum dynamics, including a $XY$$ZZ$ model which cannot be reduced to free fermions.
 [137] arXiv:2406.13065 (crosslist from physics.optics) [pdf, other]

Title: SelfHybridized ExcitonPolariton PhotovoltaicsSubjects: Optics (physics.optics); Mesoscale and Nanoscale Physics (condmat.meshall); Materials Science (condmat.mtrlsci)
Excitonic semiconductors are attractive for nextgeneration photovoltaics (PVs) with lower cost, lighter weight, and lower material consumption than conventional technologies. Among them, transition metal dichalcogenide materials like WS2 are especially interesting due to exceptionally strong lightmatter interaction. Photocurrent generation in excitonic PVs relies on exciton diffusion to heterointerfaces. However, efficiencies of excitonic PVs are often limited by short exciton diffusion lengths. Here we report that the strong coupling of excitons to cavity photons in a WS2 absorber layer can enhance the external quantum efficiency by a factor of >10, internal quantum efficiency by a factor of ~3, and power conversion efficiency of excitonic PVs by an order of magnitude. The resulting hybrid states, excitonpolaritons, enhance the resonant absorption and exciton transport while the use of the WS2 layer as its own optical cavity enables broadband absorption. Thickness dependent device characterization reveals anomalous internal quantum efficiency and fill factor behavior that are attributed to novel excitonpolariton transport. Excitonpolariton enhanced transport occurs for both resonant and offresonant excitation, emphasizing the value and practicality of the selfhybridized device structure. Our work presents a route towards excitonic PVs with broadband absorption and improved exciton transport without strict requirements of donor/acceptor structure of other excitonic PVs.
 [138] arXiv:2406.13085 (crosslist from physics.appph) [pdf, other]

Title: Ultralow thermal conductance across the [FePt/hBN/FePt] interfacechengchao Xu, Enbo Zhang, BoYuan Yang, B.S.D.Ch.S. Varaprasad, David E. Laughlin, JianGang (Jimmy)ZhuComments: 22 page, 5 figuresSubjects: Applied Physics (physics.appph); Mesoscale and Nanoscale Physics (condmat.meshall); Materials Science (condmat.mtrlsci)
Heat transfer in nanocomposite materials has attracted great interest for various applications. Multilayer structures provide an important platform to study interfacial thermal transport and to engineer materials with ultralow thermal conductivity. Here we report on the fabrication and thermal characterization of [hBN/$L1_0$FePt]xN multilayers, where hexagonal boron nitride (hBN) nanosheets (2.5 nm thick) and $L1_0$FePt layers (6.5 nm thick) alternate periodically. Differential threeomega($3\omega$) measurements reveal an ultralow effective thermal conductivity of $ 0.60 \pm 0.05 W \cdot m^{1}K^{1}$ across the multilayer films, and a low thermal boundary conductance (TBC) of $ 67.9 \pm 6.6 MW \cdot m^{2}K^{1}$ for the [FePt/hBN(2.5nm)/FePt] interface at room temperature. We attribute the ultralow thermal conductivity to the weak van der Waals bonding at hBN/FePt interfaces, which dominates the thermal resistance of the multilayer structure. These findings provide insights into the thermal transport in 2Dmaterial/metal multilayer nanostructures and suggest the [hBN/FePt] superlattice as a promising material for nanoscale thermal barrier coating. Furthermore, the obtained TBC lays the foundation for analyzing heat transfer in FePt(hBN) nanogranular films, a promising magnetic recording media which can potentially provide high thermal gradient for heatassisted magnetic recording (HAMR). This work advances the understanding of thermal transport in 2Dmaterial/metal nanocomposites and demonstrates interface engineering as an effective approach to achieve materials with ultralow thermal conductivity.
 [139] arXiv:2406.13087 (crosslist from quantph) [pdf, html, other]

Title: Thermodynamics and entanglement entropy of the nonHermitian SSH modelComments: 13 pages, 9 figuresSubjects: Quantum Physics (quantph); Strongly Correlated Electrons (condmat.strel)
Topological phase transitions are found in a variety of systems and were shown to be deeply related with a thermodynamic description through scaling relations. Here, we investigate the entanglement entropy, which is a quantity that captures the central charge of a critical model and the thermodynamics of the nonreciprocal SuSchriefferHeeger (SSH) model. Although this model has been widely studied, the thermodynamic properties reveal interesting physics not explored so far. In order to analyze the boundary effects of the model, we use Hill's thermodynamics to split the grand potential in two contributions: the extensive one, related to the bulk, and the subdivision one, related to the boundaries. Then, we derive the thermodynamic entropy for both, the edges and the bulk and the heat capacity for the bulk at the topological phase transitions. The latter is related to the central charge when the underlying theory is a conformal field theory, whereas the first reveals the resilience of the topological edge states to finite temperatures. The phase transition between phases that are adiabatically connected with the Hermitian SSH model display the wellknown behaviour of systems within the Dirac universality class, but the transition between phases with complex energies shows an unexpected critical behavior, which signals the emergence of an imaginary time crystal.
 [140] arXiv:2406.13190 (crosslist from physics.optics) [pdf, html, other]

Title: A programmable waferscale chiroptical heterostructure of twisted aligned carbon nanotubes and phase change materialsSubjects: Optics (physics.optics); Materials Science (condmat.mtrlsci)
The ability to design and dynamically control chiroptical responses in solidstate matter at wafer scale enables new opportunities in various areas. Here we present a full stack of computeraided designs and experimental implementations of a dynamically programmable, unified, scalable chiroptical heterostructure containing twisted aligned onedimensional (1D) carbon nanotubes (CNTs) and nonvolatile phase change materials (PCMs). We develop a software infrastructure based on highperformance machine learning frameworks, including differentiable programming and derivativefree optimization, to efficiently optimize the tunability of both excitonic reciprocal and linearanisotropyinduced nonreciprocal circular dichroism (CD) responses. We experimentally implement designed heterostructures with waferscale selfassembled aligned CNTs and deposited PCMs. We dynamically program reciprocal and nonreciprocal CD responses by inducing phase transitions of PCMs, and nonreciprocal responses display polarity reversal of CD upon sample flipping in broadband spectral ranges. All experimental results agree with simulations. Further, we demonstrate that the vertical dimension of heterostructure is scalable with the number of stacking layers and aligned CNTs play dual roles  the layer to produce CD responses and the Joule heating electrode to electrically program PCMs. This heterostructure platform is versatile and expandable to a library of 1D nanomaterials and electrooptic materials for exploring novel chiral phenomena and photonic and optoelectronic devices.
 [141] arXiv:2406.13211 (crosslist from quantph) [pdf, html, other]

Title: Amplitude Amplification and Estimation using quantum kicked rotorComments: 10 pages, 9 figuresSubjects: Quantum Physics (quantph); Quantum Gases (condmat.quantgas)
The quantum kicked rotor had been widely used for studying quantum chaos and the physics of Anderson localization. It is shown that QKR can be used to design a quantum algorithm to perform unstructured search. This is illustrated through amplitude amplification, a generalization of Grover's search algorithm, using QKR system. Further, QKR is employed for amplitude estimation when the amplitude of the marked states is unknown. It is also shown that dynamical localization in QKR can be exploited to enhance the performance of the amplitude amplification algorithm by reducing the average runtime. The sensitivity of the success probability of unstructured search to detuning from resonance and the effects of noisy kick strengths are analyzed and the robustness of the QKR based algorithm is shown. The experimental feasibility of every component of the algorithm is discussed.
 [142] arXiv:2406.13220 (crosslist from physics.medph) [pdf, other]

Title: Acoustically Transparent Aluminabased Cranial Implants Enhance Ultrasound Transmission Through a Combined MechanoAcoustic Resonant EffectMario Ibrahin Gutierrez, Pathikumar Sellappan, Elias H. Penilla, Irais PobleteNaredo, Arturo Vera, Lorenzo Leija, Javier E. GarayComments: Journal of Physics: MaterialsSubjects: Medical Physics (physics.medph); Materials Science (condmat.mtrlsci)
Therapeutic ultrasound for brain stimulation has increased in the last years. This energy has shown promising results for treating Alzheimers disease, Parkinsons disease, and traumatic brain injury, among other conditions. However, the application of ultrasound in the brain should trespass a natural but highly attenuating and distorting barrier, the cranium. Implantable ceramic materials can be used to replace part of the cranium as an alternate method to enhance ultrasound transmission. In this work, it is presented the acoustic characterization of alumina ceramic disks that can be employed as cranial implants for acoustic windowstothebrain. Alumina samples were prepared using currentactivated pressureassisted densification and were acoustically characterized. Acoustic impedance and attenuation of the samples were determined for different porosities. Additionally, measured and modeled acoustic fields are presented and analyzed in terms of the total ultrasound transmitted through the ceramics. Results indicate a resonant behavior in the alumina disks when the thickness corresponds to a halfwavelength of ultrasound; this resonance permits a total of 95.4% of ultrasound transmission; for thicknesses out of the resonant zone, transmission is 53.0%. Alumina proves to be an excellent medium for ultrasound transmission that, in conjunction with its mechanical and optical properties, can be useful for cranium replacement in mixed optoacoustic applications.
 [143] arXiv:2406.13238 (crosslist from physics.medph) [pdf, other]

Title: Fast SmallAngle Xray Scattering Tensor Tomography: An Outlook into Future Applications in Life SciencesChristian Appel, Margaux Schmeltz, Irene RodriguezFernandez, Lukas Anschuet, Leonard C. Nielsen, Ezequiel Panepucci, Tomislav Marijolovic, Klaus Wakonig, Aleksandra Ivanovic, Anne Bonnin, Filip Leonarski, Justyna Wojdyla, Takashi Tomizaki, Manuel GuizarSicairos, Kate Smith, John H. Beale, Wayne Glettig, Katherine McAuley, Oliver Bunk, Meitian Wang, Marianne LiebiSubjects: Medical Physics (physics.medph); Materials Science (condmat.mtrlsci)
Small AngleXray Scattering Tensor Tomography (SASTT) is a relatively new, but powerful technique for studying the multiscale architecture of hierarchical structures, which is of particular interest for life science applications. Currently, the technique is very demanding on synchrotron beamtime, which limits its applications, especially for cases requiring a statistically relevant amount of sample. This study reports the first SASTT measurement at a macromolecular Xray crystallography beamline, PXI at the SLS, with an improvement in data acquisition time from 96 h/Mvoxel in the pilot experiments to 6 h/Mvoxel, defining a new standard for fast SASTT and allowing the measurement of a full tomogram in 1.2 hours. Measurements were performed on the long and lenticular process of the incus bone, one of the three human auditory ossicles. The main orientation and degree of alignment of the mineralised collagen fibrils are characterised, as well as the size and shape of the mineral particles which show relevant variations in different tissue locations. The study reveals three distinct regions of high fibril alignment, most likely important pathways of sound throughout the ossicular chain, and highlights the potential of the technique to aid in future developments in middle ear reconstructive surgery.
 [144] arXiv:2406.13265 (crosslist from cs.LG) [pdf, html, other]

Title: Molecule Graph Networks with Manybody Equivariant InteractionsSubjects: Machine Learning (cs.LG); Materials Science (condmat.mtrlsci)
Message passing neural networks have demonstrated significant efficacy in predicting molecular interactions. Introducing equivariant vectorial representations augments expressivity by capturing geometric data symmetries, thereby improving model accuracy. However, twobody bond vectors in opposition may cancel each other out during message passing, leading to the loss of directional information on their shared node. In this study, we develop Equivariant Nbody Interaction Networks (ENINet) that explicitly integrates equivariant manybody interactions to preserve directional information in the message passing scheme. Experiments indicate that integrating manybody equivariant representations enhances prediction accuracy across diverse scalar and tensorial quantum chemical properties. Ablation studies show an average performance improvement of 7.9% across 11 out of 12 properties in QM9, 27.9% in forces in MD17, and 11.3% in polarizabilities (CCSD) in QM7b.
 [145] arXiv:2406.13296 (crosslist from physics.compph) [pdf, html, other]

Title: Critical temperature of the classical XY model via autoencoder latent space samplingComments: 6 pages, 11 figures. To be published in Physical Review ESubjects: Computational Physics (physics.compph); Statistical Mechanics (condmat.statmech)
The classical XY model has been consistently studied since it was introduced more than six decades ago. Of particular interest has been the twodimensional spin model's exhibition of the BerezinskiiKosterlitzThouless (BKT) transition. This topological phenomenon describes the transition from bound vortexantivortex pairs at low temperatures to unpaired or isolated vortices and antivortices above some critical temperature. In this work we propose a novel machine learning based method to determine the emergence of this phase transition. An autoencoder was used to map states of the XY model into a lower dimensional latent space. Samples were taken from this latent space to determine the thermal average of the vortex density which was then used to determine the critical temperature of the phase transition.
 [146] arXiv:2406.13320 (crosslist from nlin.PS) [pdf, html, other]

Title: Electromagnetic breathing dromionlike structures in an anisotropic ferromagnetic mediumComments: Accepted for publication in Journal of Magnetism and Manetic MaterialsSubjects: Pattern Formation and Solitons (nlin.PS); Other Condensed Matter (condmat.other); Exactly Solvable and Integrable Systems (nlin.SI)
The influence of Gilbert damping on the propagation of electromagnetic waves (EMWs) in an anisotropic ferromagnetic medium is investigated theoretically. The interaction of the magnetic field component of the electromagnetic wave with the magnetization of a ferromagnetic medium has been studied by solving the associated Maxwell's equations coupled with a LandauLifshitzGilbert (LLG) equation. When small perturbations are made on the magnetization of the ferromagnetic medium and magnetic field along the direction of propagation of electromagnetic wave by using the reductive perturbation method, the associated nonlinear dynamics is governed by a timedependent damped derivative nonlinear Schrodinger (TDDNLS) equation. The Lagrangian density function is constructed by using the variational method to solve the TDDNLS equation to understand the dynamics of the system under consideration. The propagation of EMW in a ferromagnetic medium with inherent Gilbert damping admits very interesting nonlinear dynamical structures. These structures include Gilbert dampingmanaging symmetrically breathing solitons, localized erupting electromagnetic breathing dromionlike modes of excitations, breathing dromionlike soliton, decaying dromionlike modes and an unexpected creationannihilation mode of excitations in the form of growingdecaying dromionlike modes.
 [147] arXiv:2406.13325 (crosslist from physics.appph) [pdf, other]

Title: Advances in perovskite nanocrystals and nanocomposites for scintillation applicationsJournalref: ACS Energy Letters 2024Subjects: Applied Physics (physics.appph); Materials Science (condmat.mtrlsci)
In recent years, the field of radiation detection has witnessed a paradigm shift with the emergence of plastic scintillators incorporating perovskite nanocrystals (PNCs). This innovative class of scintillators not only capitalizes on the superior luminescent properties of PNCs but also harnesses the flexibility and processability of polymers. This review explores the intricate landscape of synthesizing and fabricating scintillating PNCs and nanocomposites, delving into the methods employed in their production. From solutionbased methods to innovative solidstate approaches, the synthesis of PNCs for scintillators application is explored comprehensively. Furthermore, embedding strategies within polymeric matrices are scrutinized, shedding light on the various techniques utilized to achieve optimal dispersion and compatibility. The evaluation of the final nanocomposites is finally discussed, with a particular emphasis on their scintillating performance and radiation hardness. Through a meticulous exploration of synthesis methodologies, embedding techniques, and performance assessments, this review aims to provide a multilayered understanding of the stateoftheart in PNCsbased nanoscintillators.
 [148] arXiv:2406.13446 (crosslist from physics.fludyn) [pdf, html, other]

Title: Linear stability of turbulent channel flow with onepoint closureComments: 13 pages, 8 figuresJournalref: Physical Review FLUIDS 9, 063906 (2024)Subjects: Fluid Dynamics (physics.fludyn); Soft Condensed Matter (condmat.soft)
For low enough flow rates, turbulent channel flow displays spatial modulations of large wavelengths. This phenomenon has recently been interpreted as a linear instability of the turbulent flow. We question here the ability of linear stability analysis around the turbulent mean flow to predict the onset and wavelengths of such modulations. Both the mean flow and the Reynolds stresses are extracted from direct numerical simulation (DNS) in periodic computational domains of different size. The OrrSommerfeldSquire formalism is used here, with the turbulent viscosity either ignored, evaluated from DNS, or modeled using a simple onepoint closure model. Independently of the closure model and the domain size, the mean turbulent flow is found to be linearly stable, in marked contrast with the observed behavior. This suggests that the onepoint approach is not sufficient to predict instability, at odds with other turbulent flow cases. For generic wallbounded shear flows we discuss how the correct models for predicting instability could include fluctuations in a more explicit way.
 [149] arXiv:2406.13517 (crosslist from quantph) [pdf, html, other]

Title: Quantifying nonHermiticity using single and manyparticle quantum propertiesComments: 13 pages, 6 figuresSubjects: Quantum Physics (quantph); Quantum Gases (condmat.quantgas); Strongly Correlated Electrons (condmat.strel)
The nonHermitian paradigm of quantum systems displays salient features drastically different from Hermitian counterparts. In this work, we focus on one such aspect, the difference of evolving quantum ensembles under $H_{\mathrm{nh}}$ (right ensemble) versus its Hermitian conjugate, $H_{\mathrm{nh}}^{\dagger}$ (left ensemble). We propose a formalism that quantifies the (dis)similarity of these right and left ensembles, for single as well as manyparticle quantum properties. Such a comparison gives us a scope to measure the extent to which nonHermiticity gets translated from the Hamiltonian into physically observable properties. We test the formalism in two cases: First, we construct a nonHermitian Hamiltonian using a set of imperfect Bell states, showing that the nonHermiticity of the Hamiltonian does not automatically comply with the nonHermiticity at the level of observables. Second, we study the interacting HatanoNelson model with asymmetric hopping as a paradigmatic quantum manybody Hamiltonian. Interestingly, we identify situations where the measures of nonHermiticity computed for the Hamiltonian, for single, and for manyparticle quantum properties behave distinctly from each other. Thus, different notions of nonHermiticity can become useful in different physical scenarios. Furthermore, we demonstrate that the measures can mark the model's ParityTime (PT) symmetrybreaking transition. Our findings can be instrumental in unveiling new exotic quantum phases of nonHermitian quantum manybody systems as well as in preparing resourceful states for quantum technologies.
 [150] arXiv:2406.13523 (crosslist from physics.appph) [pdf, html, other]

Title: Measurement of the Crystallization and Phase Transition of Niobium Dioxide ThinFilms for Neuromorphic Computing Applications Using a Tube Furnace Optical Transmission SystemZachary R. Robinson, Karsten Beckmann, James Michels, Vincent Daviero, Elizabeth A. Street, Fiona Lorenzen, Matthew C. Sullivan, Nathaniel Cady, Alexander Kozen, Marc CurrieSubjects: Applied Physics (physics.appph); Materials Science (condmat.mtrlsci); Emerging Technologies (cs.ET)
Significant research has focused on lowpower stochastic devices built from memristive materials. These devices foster neuromorphic approaches to computational efficiency enhancement in merged biomimetic and CMOS architectures due to their ability to phase transition from a dielectric to a metal at an increased temperature. Niobium dioxide has a volatile memristive phase change that occurs $\sim$800$^\circ$C~that makes it an ideal candidate for future neuromorphic electronics. A straightforward optical system has been developed on a horizontal tube furnace for \emph{in situ} spectral measurements as an asgrown \NbtOf\ film is annealed and ultimately crystallizes as \NbOt. The system measures the changing spectral transmissivity of \NbtOf\ as it undergoes both reduction and crystallization processes. We were also able to measure the transition from metallictononmetallic \NbOt\ during the cooldown phase, which is shown to occur about 100$^\circ$C~ lower on a sapphire substrate than fused silica. After annealing, the material properties of the \NbtOf\ and \NbOt\ were assessed via Xray photoelectron spectroscopy, Xray diffraction, and 4point resistivity, confirming that we have made crystalline \NbOt.
 [151] arXiv:2406.13591 (crosslist from physics.appph) [pdf, other]

Title: Highly Sensitive Labelfree Biomolecular Detection Using AuWS2 Nanohybrid Based SERS SubstratesOm Prakash, Abhijith T, Priya Nagpal, Vivekanandan Perumal, Supravat Karak, Udai B. Singh, Santanu GhoshSubjects: Applied Physics (physics.appph); Materials Science (condmat.mtrlsci)
Recent advancements in nanotechnology have led to the development of surfaceenhanced Raman spectroscopy (SERS) based rapid and lowcost technologies for ultrasensitive labelfree detection and identification of molecular analytes. Herein, we utilized the synergistic plasmonic and chemical enhancement effects of AuWS2 nanohybrids to attain the highintensity Raman signals of targeted analytes. To develop these nanohybrids, a series of monodispersed Au nanoparticles (NPs) of varying diameters from 20 to 80 nm was chemically synthesized and successively blended with liquidphase exfoliated WS2 nanoflakes of average lateral size 90 nm. They provided a maximum enhancement factor (EF) of ~1.80 109 corresponding to the characteristic peaks at 1364 cm1 and 1512 cm1 for R6G analyte molecules. Theoretical studies based on the finitedifference timedomain simulations on AuWS2 nanohybrid systems revealed a huge fieldintensity enhancement with an EF of more than 1000 at the plasmonic hotspots, which was induced by the strong coupling of individual plasmon oscillations of the adjacent Au NPs upon light interactions. These electromagnetic effects along with the chemical enhancement effects of WS2 nanoflakes were found to be mainly responsible for such huge enhancement in Raman signals. Furthermore, these hybrids were successfully employed for achieving highly sensitive detection of the E. coli ATCC 35218 bacterial strain with a concentration of 104 CFU/mL in phosphatebuffered saline media, indicating their real capabilities for practical scenarios. The findings of the present study will indeed provide vital information in the development of innovative nanomaterialbased biosensors, that will offer new possibilities for addressing critical public health concerns.
 [152] arXiv:2406.13610 (crosslist from physics.chemph) [pdf, other]

Title: Towards the optimization of a perovskitebased room temperature ozone sensor: A multifaceted approach in pursuit of sensitivity, stability, and understanding of mechanismAikaterini Argyrou, Rafaela Maria Giappa, Emmanouil Gagaoudakis, Vasilios Binas, Ioannis Remediakis, Konstantinos Brintakis, Athanasia Kostopoulou, Emmanuel StratakisComments: Main document 35 pages, 6 panel figures. Support information 28 pages, 43 figuresSubjects: Chemical Physics (physics.chemph); Materials Science (condmat.mtrlsci)
Metal halide perovskites (MHPs) have attracted significant attention owing to their simple manufacturing process and unique optoelectronic properties. Their reversible electrical or optical properties changes in response to oxidizing or reducing environments make them prospective materials for gas detection technologies. Despite advancements in perovskitebased sensor research, the mechanisms behind perovskitegas interactions, vital for sensor performance, are still unexclusive. This work presents the first evaluation of the sensing performance and longterm stability of MHPs, considering factors such as halide composition variation and Mn doping levels. The research reveals a clear correlation between halide composition and sensing behavior, with Brrich sensors displaying a ptype response to O3 gas, while Clbased counterparts exhibit an ntype sensing behavior. Notably, Mndoping significantly enhances the O3 sensing performance by facilitating the gas adsorption process, as supported by both atomistic simulations and experimental evidence. Longterm evaluation of the sensors provides valuable insights into evolving sensing behaviors, highlighting the impact of dynamic instabilities over time. Overall, this research offers insights into optimal halide combination and Mndoping levels, representing a significant step forward in engineering room temperature perovskitebased gas sensors that are not only lowcost and highperforming but also durable, marking a new era in sensor technology.
 [153] arXiv:2406.13643 (crosslist from hepth) [pdf, html, other]

Title: Geometry of Classical NambuGoldstone FieldsComments: 20 pagesSubjects: High Energy Physics  Theory (hepth); Strongly Correlated Electrons (condmat.strel); High Energy Physics  Phenomenology (hepph)
A coordinatefree formulation of first order effective field theory, in which NambuGoldstone fields are described as sections on associated bundle, is presented. This construction, which is based only on symmetry considerations, allows for a direct derivation of number and types of NambuGoldstone fields in a classical field theory without any reference to effective Lagrangian. A central role in classification is shown to be played by Lorentzsymmetry breaking order parameter which induces symplectic structure in the field space of the theory.
 [154] arXiv:2406.13671 (crosslist from hepth) [pdf, html, other]

Title: Topological Equivalence Theorem and DoubleCopy for ChernSimons Scattering AmplitudesComments: 8+5 pages, to match Journal Version. This Letter paper is a companion of the systematic longer paper arXiv:2110.05399 (46pp)Journalref: Research 6 (2023) 0072Subjects: High Energy Physics  Theory (hepth); Strongly Correlated Electrons (condmat.strel); General Relativity and Quantum Cosmology (grqc)
We study the mechanism of topological massgeneration for 3d ChernSimons gauge theories and propose a brandnew Topological Equivalence Theorem to connect scattering amplitudes of the physical gauge boson states to that of the transverse states under high energy expansion. We prove a general energy cancellation mechanism for $N$point physical gauge boson amplitudes, which predicts large cancellations of $E^{4L}\to E^{(4L) N}$ at any $L$loop level ($L\geqslant 0$). We extend the doublecopy approach to construct massive graviton amplitudes and study their structures. We newly uncover a series of strikingly large energy cancellations $E^{12}\to E^1$ of the treelevel fourgraviton scattering amplitude under high energy expansion and establish a new correspondence between the two energy cancellations in the topologically massive YangMills gauge theory and the topologically massive gravity theory. We further study the scattering amplitudes of ChernSimons gauge bosons and gravitons in the nonrelativistic limit.
 [155] arXiv:2406.13678 (crosslist from quantph) [pdf, html, other]

Title: Simulating open quantum systems with giant atomsComments: 15+4 pages, 8+2 figures, source codes will be available at this https URLSubjects: Quantum Physics (quantph); Strongly Correlated Electrons (condmat.strel)
Open quantum manybody systems are of both fundamental and applicational interest. However, it remains an open challenge to simulate and solve such systems, both with stateoftheart classical methods and with quantumsimulation protocols. To overcome this challenge, we introduce a simulator for open quantum manybody systems based on giant atoms, i.e., atoms (possibly artificial), that couple to a waveguide at multiple points, which can be wavelengths apart. We first show that a simulator consisting of two giant atoms can simulate the dynamics of two coupled qubits, where one qubit is subject to different drive amplitudes and dissipation rates. This simulation enables characterizing the quantum Zeno crossover in this model. We further show that by equipping the simulator with postselection, it becomes possible to simulate the effective nonHermitian Hamiltonian dynamics of the system and thereby characterize the transition from oscillatory to nonoscillatory dynamics due to varying dissipation rates. We demonstrate and analyze the robustness of these simulation results against noise affecting the giant atoms. Finally, we discuss and show how giantatombased simulators can be scaled up for digitalanalog simulation of large open quantum manybody systems, e.g., generic dissipative spin models.
 [156] arXiv:2406.13804 (crosslist from physics.compph) [pdf, html, other]

Title: Elasticity and acoustic velocities of $\delta$AlOOH at extreme conditions: a methodology assessmentSubjects: Computational Physics (physics.compph); Materials Science (condmat.mtrlsci); Geophysics (physics.geoph)
Hydrous phases play a fundamental role in the deepwater cycle on Earth. Understanding their stability and thermoelastic properties is essential for constraining their abundance using seismic tomography. However, determining their elastic properties at extreme conditions is notoriously challenging. The challenges stem from the complex behavior of hydrogen bonds under high pressures and temperatures (P,Ts). In this study, we evaluate how advanced molecular dynamics simulation techniques can address these challenges by investigating the adiabatic elasticity and acoustic velocities of $\delta$AlOOH, a critical and prototypical highpressure hydrous phase. We compared the performances of three methods to assess their viability and accuracy. The thermoelastic tensor was computed up to 140 GPa and temperatures up to 2,700 K using molecular dynamics with a DeePMD machinelearning interatomic potential based on the SCAN metaGGA functional. The excellent agreement with ambient condition singlecrystal ultrasound measurements and the correct description of velocity changes induced by Hbond disordersymmetrization transition observed at 10 GPa in Brillouin scattering measurements underscores the accuracy and efficacy of our approach.
 [157] arXiv:2406.13830 (crosslist from quantph) [pdf, html, other]

Title: Quantum spin systems: toroidal classification and geometric dualityVahid AzimiMousolou, Anders Bergman, Anna Delin, Olle Eriksson, Manuel Pereiro, Danny Thonig, Erik SjöqvistComments: 6 pages, 2 figuresSubjects: Quantum Physics (quantph); Mesoscale and Nanoscale Physics (condmat.meshall)
Toroidal classification and geometric duality in quantum spin systems is presented. Through our classification and duality, we reveal that various bipartite quantum features in magnonsystems can manifest equivalently in both bipartite ferromagnetic and antiferromagnetic materials, based upon the availability of relevant Hamiltonian parameters. Additionally, the results highlight the antiferromagnetic regime as an ultrafast dual counterpart to the ferromagnetic regime, both exhibiting identical capabilities for quantum spintronics and technological applications. Concrete illustrations are provided, demonstrating how splitting and squeezing types of twomode magnon quantum correlations can be realized across ferro and antiferromagnetic regimes.
 [158] arXiv:2406.13832 (crosslist from physics.fludyn) [pdf, html, other]

Title: Poiseuille flow for a simplified pseduoplastic rheologySubjects: Fluid Dynamics (physics.fludyn); Soft Condensed Matter (condmat.soft)
Poiseuille flow in cylindrical and planar geometries with a simplified, pseudoplastic (shear thinning) rheology characterized by constant viscosity plateaus above and below a transition strain rate is considered. Analytical, steady state solutions for velocity profile and volume flux are formulated. Transient flow development is addressed numerically and compared to the theory in the steady state limit. Stationary flow is approached after the momentum diffusion timescale based on the spatially dominant kinematic viscosity. For large viscosity ratio and shear thinning region confined near the domain boundary, velocity distributions are quasiplug like with large boundary to interior strain rate ratio.
 [159] arXiv:2406.13921 (crosslist from quantph) [pdf, html, other]

Title: Quantum Enhanced Sensitivity through ManyBody Bloch OscillationsSubjects: Quantum Physics (quantph); Strongly Correlated Electrons (condmat.strel)
We investigate the sensing capacity of nonequilibrium dynamics in quantum systems exhibiting Bloch oscillations. By focusing on resource efficiency of the probe, quantified by quantum Fisher information, we find different scaling behaviors in two different phases, namely localized and extended. Our results provide a quantitative ansatz for quantum Fisher information in terms of time, probe size, and the number of excitations. In the longtime regime, the quantum Fisher information is a quadratic function of time, touching the Heisenberg limit. The system size scaling drastically depends on the phase changing from superHeisenberg scaling in the extended phase to sizeindependent behavior in the localized phase. Furthermore, increasing the number of excitations always enhances the precision of the probe, although, in the interacting systems the enhancement becomes less eminent than the noninteracting probes, which is due to induced localization by interaction between excitations.
 [160] arXiv:2406.13946 (crosslist from physics.appph) [pdf, other]

Title: Ferroelectric Materials for Synaptic Transistors and Their Neuromorphic ApplicationsComments: 44 pages, 7 figures,Subjects: Applied Physics (physics.appph); Materials Science (condmat.mtrlsci); Emerging Technologies (cs.ET)
After more than a hundred years of development, ferroelectric materials have demonstrated their strong potential to people, and more and more ferroelectric materials are being used in the research of ferroelectric transistors (FeFETs). As a new generation of neuromorphic devices, ferroelectric materials have attracted people's attention due to their powerful functions and many characteristics. This article summarizes the development of ferroelectric material systems in recent years and discusses the simulation of artificial synapses. The mainstream ferroelectric materials are divided into traditional perovskite structure, fluorite structure, organic polymer, and new 2D van der Waals ferroelectricity. The principles, research progress, and optimization for brain like computers of each material system are introduced, and the latest application progress is summarized. Finally, the scope of application of different material systems is discussed, with the aim of helping people screen out different material systems based on different needs.
 [161] arXiv:2406.14109 (crosslist from quantph) [pdf, html, other]

Title: Protect MeasurementInduced Phase Transition from NoiseSubjects: Quantum Physics (quantph); Disordered Systems and Neural Networks (condmat.disnn); Statistical Mechanics (condmat.statmech)
Measurementinduced phase transition (MIPT) is a novel nonequilibrium phase transition characterized by entanglement entropy. The scrambling dynamics induced by random unitary gates can protect information from lowrate measurements. However, common decoherence noises, such as dephasing, are detrimental to the volume law phase, posing a significant challenge for observing MIPT in current noisy intermediatescale quantum devices. Here, we demonstrate that incorporating quantumenhanced operations can effectively protect MIPT from environmental noise. The conditional entanglement entropy is associated with a statistical mechanics model wherein noise and quantumenhanced operations act as two competing external random fields. Then we show that an average apparatusenvironment exchange symmetry ensures the conditional entanglement entropy is a valid probe of entanglement. Furthermore, we provide numerical evidence on a (2+1)d quantum circuit under dephasing noise, demonstrating that MIPT can indeed be observed with the aid of quantumenhanced operations. This result not only serves as a concrete example of the power of quantum enhancement in combating noise but also holds experimental relevance, as the protocol is straightforward to implement in practice.
 [162] arXiv:2406.14222 (crosslist from physics.optics) [pdf, html, other]

Title: StressDependent Optical Extinction in LPCVD Silicon Nitride Measured by Nanomechanical Photothermal SensingKostas Kanellopulos, Robert G. West, Stefan Emminger, Paolo Martini, Markus Sauer, Annette Foelske, Silvan SchmidComments: Main text: 7 pages, 3 figures, 1 table Supporting Information: 4 pages, 4 figures, 1 tableSubjects: Optics (physics.optics); Mesoscale and Nanoscale Physics (condmat.meshall); Materials Science (condmat.mtrlsci); Applied Physics (physics.appph)
Understanding optical absorption in silicon nitride is crucial for cuttingedge technologies like photonic integrated circuits, nanomechanical photothermal infrared sensing and spectroscopy, and cavity optomechanics. Yet, the origin of its strong dependence on film deposition and fabrication process is not fully understood. This Letter leverages nanomechanical photothermal sensing to investigate optical extinction $\kappa_{\mathrm{ext}}$ at 632.8 nm wavelength in LPCVD SiN strings across a wide range of depositionrelated tensile stresses ($200850$ MPa). Measurements reveal a reduction in $\kappa_{\mathrm{ext}}$ from 10$^3$ to 10$^1$ ppm with increasing stress, correlated to variations in Si/N content ratio. Within the bandfluctuations framework, this trend indicates an increase of the energy bandgap with the stress, ultimately reducing absorption. Overall, this study showcases the power and simplicity of nanomechanical photothermal sensing for low absorption measurements, offering a sensitive, scatteringfree platform for material analysis in nanophotonics and nanomechanics.
 [163] arXiv:2406.14320 (crosslist from hepth) [pdf, html, other]

Title: Anyon condensation in mixedstate topological orderComments: 52 pages, 14 figuresSubjects: High Energy Physics  Theory (hepth); Strongly Correlated Electrons (condmat.strel); Mathematical Physics (mathph); Category Theory (math.CT); Quantum Physics (quantph)
We discuss anyon condensation in mixedstate topological order. The phases were recently conjectured to be classified by premodular fusion categories. Just like anyon condensation in purestate topological order, a bootstrap analysis shows condensable anyons are given by connected étale algebras. We explain how to perform generic anyon condensation including noninvertible anyons and successive condensations. Interestingly, some condensations lead to purestate topological orders. We clarify when this happens. We also compute topological invariants of equivalence classes.
 [164] arXiv:2406.14331 (crosslist from physics.optics) [pdf, html, other]

Title: Photonic and phononic modes in acoustoplasmonic toroidal nanopropellersBeatriz Castillo López de Larrinzar, Jorge M. García, Norberto Daniel LanzillottiKimura, Antonio GarcíaMartínComments: 9 pages 7 figuresSubjects: Optics (physics.optics); Mesoscale and Nanoscale Physics (condmat.meshall)
Nonconventional resonances, both acoustic and photonic, are found in metallic particles with a toroidal nanopropeller geometry that is generated by sweeping a threelobed 2Dshape along a spiral with twisting angle, ${\alpha}$. For both optical and acoustic cases, spectral location of resonances experiences a redshift as a function of ${\alpha}$. We demonstrate that the optical case can be understood as a natural evolution of resonances as the spiral length of the toroidal nanopropeller increases with ${\alpha}$, implying a huge helicity dependent absorption cross section. In the case of acoustic response, two redshifting breathing modes are identified. Additionally, even small ${\alpha}$ allows the appearance of new lowfrequency resonances, whose spectral dispersion depends on a competition between length of the generative spiral and the pitch of the toroidal nanopropeller.
 [165] arXiv:2406.14348 (crosslist from quantph) [pdf, other]

Title: Nonstabilizerness in kineticallyconstrained Rydberg atom arraysComments: 15 pages, 7 figuresSubjects: Quantum Physics (quantph); Quantum Gases (condmat.quantgas); Strongly Correlated Electrons (condmat.strel)
Nonstabilizer states are a fundamental resource for universal quantum computation. However,despite broad significance in quantum computing, the emergence of "manybody" nonstabilizerness in interacting quantum systems remains poorly understood due to its analytical intractability. Here we show that Rydberg atom arrays provide a natural reservoir of nonstabilizerness that extends beyond single qubits and arises from quantum correlations engendered by the Rydberg blockade. We demonstrate that this nonstabilizerness can be experimentally accessed in two complementary ways, either by performing quench dynamics or via adiabatic ground state preparation. Using the analytical framework based on matrix product states, we explain the origin of Rydberg nonstabilizerness via a quantum circuit decomposition of the wave function.
 [166] arXiv:2406.14433 (crosslist from physics.appph) [pdf, other]

Title: Structural and Electrical Properties of Grafted Si/GaAsSb HeterojunctionHaris Naeem Abbasi, Seunghyun Lee Hyemin Jung, Nathan Gajowski, Yi Lu, Linus Wang, Donghyeok Kim, Jie Zhou, Jiarui Gong, Chris Chae, Jinwoo Hwang, Manisha Muduli, Subramanya Nookala, Zhenqiang. Ma, Sanjay KrishnaComments: 14 pages, 6 figuresSubjects: Applied Physics (physics.appph); Materials Science (condmat.mtrlsci)
The shortwave infrared (SWIR) wavelength, especially 1.55 um, has attracted significant attention in various areas such as highspeed optical communication and LiDAR systems. Avalanche photodiodes (APDs) are a critical component as a receiver in these systems due to their internal gain which enhances the system performance. Siliconbased APDs are promising since they are CMOS compatible, but they are limited in detecting 1.55 um light detection. This study proposes a ptype Si on ntype GaAs0.51Sb0.49 (GaAsSb) lattice matched to InP substrates heterojunction formed using a grafting technique for future GaAsSb/Si APD technology. A p+Si nanomembrane is transferred onto the GaAsSb/AlInAs/InP substrate, with an ultrathin ALDAl2O3 oxide at the interface, which behaves as both doubleside passivation and quantum tunneling layers. The devices exhibit excellent surface morphology and interface quality, confirmed by atomic force microscope (AFM) and transmission electron microscope (TEM). Also, the currentvoltage (IV) of the p+Si/nGaAsSb heterojunction shows ideal rectifying characteristics with an ideality factor of 1.15. The IV tests across multiple devices confirm high consistency and yield. Furthermore, the Xray photoelectron spectroscopy (XPS) measurement reveals that GaAsSb and Si are found to have typeII band alignment with a conduction band offset of 50 meV which is favorable for the highbandwidth APD application. The demonstration of the GaAsSb/Si heterojunction highlights the potential to advance current SWIR PD technologies.
 [167] arXiv:2406.14461 (crosslist from quantph) [pdf, html, other]

Title: Generation of manybody entanglement by collective coupling of atom pairs to cavity photonsComments: 5+11 pages, 2 figuresSubjects: Quantum Physics (quantph); Quantum Gases (condmat.quantgas)
The generation of manybody entangled states in atomic samples should be fast, as this process always involves a subtle interplay between desired quantum effects and unwanted decoherence. Here we identify a controllable and scalable catalyst that allows metrologically useful entangled states to be generated at a high rate. This is achieved by immersing a collection of bosonic atoms, trapped in a doublewell potential, in an optical cavity. In the dispersive regime, cavity photons collectively couple pairs of atoms in their ground state to a molecular state, effectively generating, photonnumber dependent atomatom interactions. These effective interactions entangle atoms at a rate that strongly scales with both the number of photons and the number of atoms. As a consequence, the characteristic time scale of entanglement formation can be much shorter than for bare atomatom interactions, effectively eliminating the decoherence due to photon losses. Here, the control of the entanglement generation rate does not require the use of Feshbach resonances, where magnetic field fluctuations can contribute to decoherence. Our protocol may find applications in future quantum sensors or other systems where controllable and scalable manybody entanglement is desired.
 [168] arXiv:2406.14490 (crosslist from hepth) [pdf, html, other]

Title: One point functions in large $N$ vector models at finite chemical potentialComments: 60 pages, 7 figuresSubjects: High Energy Physics  Theory (hepth); Statistical Mechanics (condmat.statmech); Strongly Correlated Electrons (condmat.strel)
We evaluate the thermal one point function of higher spin currents in the critical model of $U(N)$ complex scalars interacting with a quartic potential and the $U(N)$ GrossNeveu model of Dirac fermions at large $N$ and strong coupling using the Euclidean inversion formula. These models are considered in odd space time dimensions $d$ and held at finite temperature and finite real chemical potential $\mu$ measured in units of the temperature. We show that these one point functions simplify both at large spin and large $d$. At large spin, the one point functions behave as though the theory is free, the chemical potential appears through a simple prefactor which is either $\cosh\mu$ or $\sinh\mu$ depending on whether the spin is even or odd. At large $d$, but at finite spin and chemical potential, the 1point functions are suppressed exponentially in $d$ compared to the free theory. We study a fixed point of the critical GrossNeveu model in $d=3$ with 1point functions exhibiting a branch cut in the chemical potential plane. The critical exponent for the free energy or the pressure at the branch point is $3/2$ which coincides with the mean field exponent of the LeeYang edge singularity for repulsive core interactions.
Cross submissions for Friday, 21 June 2024 (showing 39 of 39 entries )
 [169] arXiv:1905.00435 (replaced) [pdf, html, other]

Title: Anomaly indicators for topological orders with $U(1)$ and timereversal symmetryComments: v2: 21 pages, 2 figures, minor changes from the first version. Version published in PRB. v3: corrected a minor error in the proof that $η_{\text{ETI}} = 1$ for Abelian topological ordersJournalref: Phys. Rev. B 100, 165129 (2019)Subjects: Strongly Correlated Electrons (condmat.strel); High Energy Physics  Theory (hepth)
We study anomalies in timereversal ($\mathbb{Z}_2^T$) and $U(1)$ symmetric topological orders. In this context, an anomalous topological order is one that cannot be realized in a strictly $(2+1)$D system but can be realized on the surface of a $(3+1)$D symmetryprotected topological (SPT) phase. To detect these anomalies we propose several anomaly indicators  functions that take as input the algebraic data of a symmetric topological order and that output a number indicating the presence or absence of an anomaly. We construct such indicators for both structures of the full symmetry group, i.e. $U(1)\rtimes\mathbb{Z}_2^T$ and $U(1)\times\mathbb{Z}_2^T$, and for both bosonic and fermionic topological orders. In all cases we conjecture that our indicators are complete in the sense that the anomalies they detect are in onetoone correspondence with the known classification of $(3+1)$D SPT phases with the same symmetry. We also show that one of our indicators for bosonic topological orders has a mathematical interpretation as a partition function for the bulk $(3+1)$D SPT phase on a particular manifold and in the presence of a particular background gauge field for the $U(1)$ symmetry.
 [170] arXiv:2009.03249 (replaced) [pdf, html, other]

Title: Unconventional U(1) to $\mathbf{Z_q}$ crossover in quantum and classical ${\bf q}$state clock modelsComments: Due to small technical error pointed out by readers, we have replaced page 20, left column, last sentence "These operators instead ... is not necessary)."Journalref: Phys. Rev. B 103, 054418 (2021)Subjects: Strongly Correlated Electrons (condmat.strel); Statistical Mechanics (condmat.statmech)
We consider twodimensional $q$state quantum clock models with quantum fluctuations connecting states with clock transitions with different choices for matrix elements. We study the quantum phase transitions in these models using quantum Monte Carlo simulations, with the aim of characterizing the crossover from emergent U(1) symmetry at the transition (for $q \ge 4$) to $Z_q$ symmetry of the ordered state. We also study classical threedimensional clock models with spatial anisotropy corresponding to the spacetime anisotropy of the quantum systems. The U(1) to ${Z_q}$ symmetry crossover in all these systems is governed by a dangerously irrelevant operator. We specifically study $q=5$ and $q=6$ models with different forms of the quantum fluctuations and different anisotropies in the classical models. We find the expected classical XY critical exponents and scaling dimensions $y_q$ of the clock fields. However, the initial weak violation of the U(1) symmetry in the ordered phase, characterized by a $Z_q$ symmetric order parameter $\phi_q$, scales in an unexpected way. As a function of the system size $L$, close to the critical temperature $\phi_q \propto L^p$, where the known value of the exponent is $p=2$ in the classical isotropic clock model. In contrast, for strongly anisotropic classical models and the quantum models we find $p=3$. For weakly anisotropic classical models we observe a crossover from $p=2$ to $p=3$ scaling. The exponent $p$ directly impacts the exponent $\nu'$ governing the divergence of the U(1) to $Z_q$ crossover length scale $\xi'$ in the thermodynamic limit, according to the relationship $\nu'=\nu(1+y_q/p)$, where $\nu$ is the conventional correlation length exponent. We present a phenomenological argument based on an anomalous renormalization of the clock field in the presence of anisotropy, possibly as a consequence of topological (vortex) line defects.
 [171] arXiv:2207.09635 (replaced) [pdf, html, other]

Title: A large deviation approach to superstatistics: thermodynamic duality symmetry between conjugate variablesComments: 9 pages, 3 figureSubjects: Statistical Mechanics (condmat.statmech)
Superstatistics generalizes Boltzmann statistics by assuming spatiotemporal fluctuations of the intensive variables. It has many applications in the analysis of experimental and simulated data. The fluctuation of the intensity variable is the key to the validity of superstatistical theory, but the law of its distribution is still unclear. In the framework of large deviation theory, we show that the fluctuation of the intensive variable of superstatistics emerges naturally from measurements in the large data limit. Combining Bayes' theorem, we demonstrate the conditional probability distribution of the intensity variable also follows the Boltzmann statistics and the conjugate variable of the intensive variable is the extensive variable, indicating a thermodynamic duality symmetry between conjugate variables in the superstatistical systems. A new thermodynamic relation between the entropy functions of conjugate variables is obtained. We utilized a simple Ising model with fluctuating temperature to verify the dual relationship between temperature and energy. Our work may contribute to the understanding of statistical physics in complex systems and Bayesian inference.
 [172] arXiv:2211.07401 (replaced) [pdf, other]

Title: Relation between Boltzmann, FermiDirac, and BoseEinstein distribution: Quantum principle for bosons, predicting a bosonic vacuum state of positive energy, a candidate for dark energy and dark matterComments: 17 pages, 2 figuresSubjects: Statistical Mechanics (condmat.statmech)
We obtain two fundamental conditions that characterize a thermal equilibrium between two energy levels: (i) the total energy must be equal in both levels and (ii) the temperature must be equal for all particles. Exploiting these two conditions, we derive a differential equation of thermal equilibrium that holds for all types of particles. Integration delivers the Boltzmann distribution, suggesting that it is the general distribution of thermal equilibrium. With the fermionic excitedstate population number n2 and groundstate population number n1, Pauli's exclusion principle is formalized as n1 + n2 = 1. Exploiting Einstein's rateequation approach to Planck's law of blackbody radiation and introducing a bosonic excitedstate population number n2 and groundstate population number n1, we derive the quantum principle for bosons, n1  n2 = 1. Utilizing either quantum principle in the integration of the differential equation of thermal equilibrium or entering either quantum principle into the Boltzmann distribution delivers the FermiDirac or BoseEinstein distribution. The ratio of fermionic or bosonic population numbers, n2 / n1, follows the Boltzmann distribution. These results suggest that the FermiDirac and BoseEinstein distributions are special cases of the Boltzmann distribution, ruled by Pauli's exclusion principle or the quantum principle for bosons. In the quantum principle for bosons, the righthand side represents a vacuum state. Consequently, a populated vacuum state should exist for all bosons. In the same manner as the vacuum photon is undetectable, the vacuum states of all bosons should be undetectable; therefore, these states are dark states. The vacuum states of all bosons contribute to dark energy, while only the vacuum states of matter bosons contribute to dark matter, supporting the fact that the amount of dark energy exceeds that of dark matter in the universe.
 [173] arXiv:2301.04345 (replaced) [pdf, html, other]

Title: SymmetryPreserving Quadratic Lindbladian and Dissipation Driven Topological Transitions in Gaussian StatesComments: 8 pages, 2 figureSubjects: Mesoscale and Nanoscale Physics (condmat.meshall); Quantum Gases (condmat.quantgas); Statistical Mechanics (condmat.statmech); Strongly Correlated Electrons (condmat.strel); Quantum Physics (quantph)
The dynamical evolution of an open quantum system can be governed by the Lindblad equation of the density matrix. In this paper, we propose to characterize the density matrix topology by the topological invariant of its modular Hamiltonian. Since the topological classification of such Hamiltonians depends on their symmetry classes, a primary issue we address is determining the requirement for the Lindbladian operators, under which the modular Hamiltonian can preserve its symmetry class during the dynamical evolution. We solve this problem for the fermionic Gaussian state and for the modular Hamiltonian being a quadratic operator of a set of fermionic operators. When these conditions are satisfied, along with a nontrivial topological classification of the symmetry class of the modular Hamiltonian, a topological transition can occur as time evolves. We present two examples of dissipationdriven topological transitions where the modular Hamiltonian lies in the AIII class with U(1) symmetry and the DIII class without U(1) symmetry. By a finite size scaling, we show that this density matrix topology transition occurs at a finite time. We also present the physical signature of this transition.
 [174] arXiv:2302.08677 (replaced) [pdf, other]

Title: Inversecurrent quantum electrooscillations in a chargedensity wave insulatorTian Le, Ruiyang Jiang, Linfeng Tu, Renji Bian, Yiwen Ma, Yunteng Shi, Ke Jia, Zhilin Li, Zhaozheng Lyu, Xuewei Cao, Jie Shen, Guangtong Liu, Youguo Shi, Fucai Liu, Yi Zhou, Li Lu, Fanming QuComments: 33 pages, 17 figuresJournalref: Physical Review B 109, 245123 (2024)Subjects: Mesoscale and Nanoscale Physics (condmat.meshall); Materials Science (condmat.mtrlsci); Strongly Correlated Electrons (condmat.strel)
Quantum magnetooscillations have long been a vital subject in condensed matter physics, with ubiquitous quantum phenomena and diverse underlying physical mechanisms. Here, we demonstrate the intrinsic and reproducible DCcurrentdriven quantum electrooscillations with a periodicity in the inverse of the current (1/I), in quasionedimensional chargedensitywave (CDW) insulators (TaSe$_4$)$_2$I and TaS$_3$ nanowires. Such oscillations manifest in the nearly infinite Fröhlich conductivity region where the undamped CDW flow forms in a finite electric current, and finally disappear after the oscillation index n reaches 1. A systematic investigation on the effect of temperature and magnetic field establishes that the observed electrooscillations are a coherent quantum phenomenon. We discuss the possibilities of the physical mechanisms, including the formation of slidingdriven inherent Floquet sidebands. Our results introduce a new member in the family of quantum oscillations, and shed light on plausible avenues to explore novel physics and potential applications of coherent densitywave condensates.
 [175] arXiv:2303.11202 (replaced) [pdf, html, other]

Title: Effect of ion irradiation on superconducting thin filmsKatja Kohopää, Alberto Ronzani, Robab Najafi Jabdaraghi, Arijit Bera, Mário Ribeiro, Dibyendu Hazra, Jorden Senior, Mika Prunnila, Joonas Govenius, Janne S. Lehtinen, Antti KemppinenSubjects: Superconductivity (condmat.suprcon)
We demonstrate ion irradiation by argon or gallium as a waferscale postprocessing method to increase disorder in superconducting thin films. We study several widely used superconductors, both singleelements and compounds. We show that ion irradiation increases normalstate resistivity in all our films, which is expected to enable tuning their superconducting properties, for example, toward higher kinetic inductance. We observe an increase of superconducting transition temperature for Al and MoSi, and a decrease for Nb, NbN, and TiN. In MoSi, ion irradiation also improves the mixing of the two materials. We demonstrate fabrication of an amorphous and homogeneous film of MoSi with uniform thickness, which is promising, e.g., for superconducting nanowire singlephoton detectors.
 [176] arXiv:2304.11716 (replaced) [pdf, html, other]

Title: Quantum Spin Supersolid as a precursory Dirac Spin Liquid in a Triangular Lattice AntiferromagnetComments: 13 pages, 9 figures. To appear in Phys Rev ResearchSubjects: Strongly Correlated Electrons (condmat.strel); Materials Science (condmat.mtrlsci)
Based on the recent experiments on the triangular lattice antiferromagnet Na$_2$BaCo(PO$_4$)$_2$, we propose the easyaxis XXZ spin1/2 model on the triangular lattice, that exhibits a quantum spin supersolid, to be a precursory Dirac spin liquid. Despite the presence of a threesublattice magnetic order as a spin supersolid, we suggest that this system is close to a Dirac spin liquid by exploring its spectroscopic response. The physical consequence is examined from the spectroscopic response, and we establish the continuous spectra near the M point in addition to the K point excitation from the spinon continuum on top of the threesublattice order. Moreover, the satellite peaks were predicted at the midpoints connecting the $\Gamma$ and K points. This proposal offers a plausible understanding of the recent inelastic neutron scattering measurement in Na$_2$BaCo(PO$_4$)$_2$ and could inspire further research in relevant models and materials, such as K$_2$Co(SeO$_3$)$_2$ and Rb$_2$Co(SeO$_3$)$_2$, and even more anisotropic magnets like PrMgAl$_{11}$O$_{19}$.
 [177] arXiv:2304.12266 (replaced) [pdf, html, other]

Title: Magnetic plateaus and jumps in a spin1/2 ladder with alternate IsingHeisenberg rungs: a field dependent studyComments: 15 pages, 9 figuresSubjects: Strongly Correlated Electrons (condmat.strel)
We study a frustrated twoleg spin1/2 ladder with alternate Ising and isotropic Heisenberg rung exchange interactions, whereas, interactions along legs and diagonals are Ising type. The groundstate (GS) of this model has four exotic phases: (i) the stripe rung ferromagnet (SRFM), (ii) the anisotropic antiferromagnet (AAFM), (iii) the Dimer, and (iv) the stripe leg ferromagnet (SLFM) in absence of any external magnetic field. In this work, we study the effect of externally applied longitudinal and transverse fields on GS phases and note that there are two plateaus with persite magnetization $1/4$ and $1/2$. There is another plateau at zero magnetization due to a finite spin gap in the presence of a longitudinal field. The exact diagonalization (ED) and the transfer matrix (TM) methods are used to solve the model Hamiltonian and the mechanism of plateau formation is analyzed using spin density, quantum fidelity, and quantum concurrence. In the (i) SRFM phase, Ising exchanges are dominant for all spins but the Heisenberg rungs are weak, and therefore, the magnetization shows a continuous transition as a function of the transverse field. In the other three phases [(ii)(iv)], the Ising dimer rungs are weak and those are broken first to reach a plateau with persite magnetization $1/4$, having a large gap which is closed by further application of the transverse field.
 [178] arXiv:2305.06373 (replaced) [pdf, html, other]

Title: Spin exchangeenabled quantum simulator for largescale nonAbelian gauge theoriesComments: $15$ pages, $12$ figuresSubjects: Quantum Gases (condmat.quantgas); Strongly Correlated Electrons (condmat.strel); High Energy Physics  Lattice (heplat); Quantum Physics (quantph)
A central requirement for the faithful implementation of largescale lattice gauge theories (LGTs) on quantum simulators is the protection of the underlying gauge symmetry. Recent advancements in the experimental realizations of largescale LGTs have been impressive, albeit mostly restricted to Abelian gauge groups. Guided by this requirement for gauge protection, we propose an experimentally feasible approach to implement largescale nonAbelian $\mathrm{SU}(N)$ and $\mathrm{U}(N)$ LGTs with dynamical matter in $d+1$D, enabled by twobody spinexchange interactions realizing local emergent gaugesymmetry stabilizer terms. We present two concrete proposals for $2+1$D $\mathrm{SU}(2)$ and $\mathrm{U}(2)$ LGTs, including dynamical bosonic matter and induced plaquette terms, that can be readily implemented in current ultracoldmolecule and nextgeneration ultracoldatom platforms. We provide numerical benchmarks showcasing experimentally accessible dynamics, and demonstrate the stability of the underlying nonAbelian gauge invariance. We develop a method to obtain the effective gaugeinvariant model featuring the relevant magnetic plaquette and minimal gaugematter coupling terms. Our approach paves the way towards nearterm realizations of largescale nonAbelian quantum link models in analog quantum simulators.
 [179] arXiv:2305.19519 (replaced) [pdf, html, other]

Title: Two applications of stochastic thermodynamics to hydrodynamicsComments: 5+4 pages, 2 figuresJournalref: Phys. Rev. Research 6, L022057 (2024)Subjects: Statistical Mechanics (condmat.statmech); Fluid Dynamics (physics.fludyn)
Recently, the theoretical framework of stochastic thermodynamics has been revealed to be useful for macroscopic systems. However, despite its conceptual and practical importance, the connection to hydrodynamics has yet to be explored. In this Letter, we reformulate the thermodynamics of compressible and incompressible Newtonian fluids so that it becomes comparable to stochastic thermodynamics and unveil their connections; we obtain the housekeepingexcess decomposition of entropy production rate (EPR) for hydrodynamic systems and find a lower bound on EPR given by relative fluctuation similar to the thermodynamic uncertainty relation. These results not only prove the universality of stochastic thermodynamics but also suggest the potential extensibility of the thermodynamic theory of hydrodynamic systems.
 [180] arXiv:2306.13170 (replaced) [pdf, html, other]

Title: SPT extension of $Z_2$ quantum Ising model's ferromagnetic phaseSubjects: Strongly Correlated Electrons (condmat.strel); High Energy Physics  Theory (hepth)
This paper focuses on the creation of a model with explicitly defined symmetryprotected topological (SPT) phases on a triangular lattice as an extension of $Z_2$ Ising model's ferromagnetic phase. Unlike in previously known similar works, this model is based on an initially interacting system which is known to describe experimentally realizable physical systems. The Hamiltonian for these edge states contains fourpoint spin interactions between nexttonext nearest neighbors. As an initially interacting A generic technique for creating SPT models is developed, allowing for the construction of translationinvariant edge models.
 [181] arXiv:2307.05257 (replaced) [pdf, html, other]

Title: Right On Time: Ultrafast Charge Separation Before Hybrid Exciton FormationLukas Gierster, Olga Turkina, JanChristoph Deinert, Sesha Vempati, Elsie Baeta, Yves Garmshausen, Stefan Hecht, Claudia Draxl, Julia StählerSubjects: Materials Science (condmat.mtrlsci); Soft Condensed Matter (condmat.soft); Chemical Physics (physics.chemph); Computational Physics (physics.compph)
Organic/inorganic hybrid systems offer great potential for novel solar cell design combining the tunability of organic chromophore absorption properties with high charge carrier mobilities of inorganic semiconductors. However, often such material combinations do not show the expected performance: while ZnO, for example, basically exhibits all necessary properties for a successful application in lightharvesting, it was clearly outpaced by TiO$_2$ in terms of charge separation efficiency. The origin of this deficiency has long been debated. This study employs femtosecond timeresolved photoelectron spectroscopy and manybody ab initio calculations to identify and quantify all elementary steps leading to the suppression of charge separation at an exemplary organic/ZnO interface. We demonstrate that charge separation indeed occurs efficiently on ultrafast (350 fs) timescales, but that electrons are recaptured at the interface on a 100 ps timescale and subsequently trapped in a strongly bound (0.7 eV) hybrid exciton state with a lifetime exceeding 5 $\mu$s. Thus, initially successful charge separation is followed by delayed electron capture at the interface, leading to apparently low charge separation efficiencies. This finding provides a sufficiently large timeframe for countermeasures in device design to successfully implement specifically ZnO and, moreover, invites material scientists to revisit charge separation in various kinds of previously discarded hybrid systems.
 [182] arXiv:2307.05955 (replaced) [pdf, html, other]

Title: Microscopic origin of quantum supersonic phenomenon in one dimensionComments: 6 pages+9pages, 4 figures + 7 figures, exact results of supersonic phenomenon, new figures and adding new resultSubjects: Quantum Gases (condmat.quantgas)
Using the Bethe ansatz (BA), we rigorously obtain nonequilibrium dynamics of an impurity with a large initial momentum $Q$ in the onedimensional (1D) interacting bosonic medium. We show that magnon and excitonlike states obtained from the BA equations drastically determine the oscillation nature of the quantum flutter with the periodicity given by $\tau_{\rm QF} = 2\pi/(\varepsilon_{\rm c}(0) \varepsilon_{\rm s}(0))$. Where the charge and spin dressed energies $\varepsilon_{\rm c,s}(0)$ are precisely given by the thermodynamical BA equations. While we further find a persistent revival dynamics of the impurity with a larger periodicity $\tau_{L} = L/\left(v_{\rm c}(Qk^*)v_{\rm s}(k^*)\right)$ than $\tau_{\rm QF}$, manifesting a quantum reflection induced by the periodic boundary conditions of a finite length $L$, here $v_{\rm c,s}$ are the sound velocities of charge and spin excitations, respectively, and $k^*$ is a characteristic momentum of the impurity to the Fermi point. Finally, we study the application of such a magnon impurity as a quantum resource for measuring the gravitational force.
 [183] arXiv:2307.06550 (replaced) [pdf, html, other]

Title: Topological Unwinding in an ExcitonPolariton Condensate ArrayComments: 11 pages, 5 figuresJournalref: Communications Physics (2024) 7:194Subjects: Quantum Gases (condmat.quantgas); Mesoscale and Nanoscale Physics (condmat.meshall); Other Condensed Matter (condmat.other)
The phase distribution in a BoseEinstein condensate can realize various topological states classified by distinct winding numbers. While states with different winding numbers are topologically protected in the linear Schrödinger equation, when nonlinearities are introduced, violations of the topological protection can occur, leading to unwinding. Excitonpolariton condensates constitute a nonlinear opendissipative system that is well suited to studying such physics. Here we show that a onedimensional array of excitonpolariton condensates displays a spontaneous phase unwinding from a $\pi$ to zerostate. We clarify that this collective mode transition is caused by the combined effect of nonlinearity and topological defects in the condensates. While the modeswitching phenomenon observed in our previous experiment was interpreted as the singleparticle mode competition, we offer an alternative explanation in terms the collective phase unwinding and find its evidence by reanalyzing the experimental data. Our results open a route towards active control of the mode switching by manipulating the topological defects in prospective quantum polaritonic devices.
 [184] arXiv:2307.10759 (replaced) [pdf, other]

Title: Highdensity singleatom electrocatalytic centers on twodimensional topological platinum tellurides with Tevacancy superstructureXin Xu, Xuechun Wang, Shuming Yu, Chenhui Wang, Guowei Liu, Hao Li, Jiangang Yang, Jing Li, Tao Sun, Xiao Hai, Lei Li, Xue Liu, Ying Zhang, Weifeng Zhang, Quan Zhang, Kedong Wang, Nan Xu, Yaping Ma, Fangfei Ming, Ping Cui, Jiong Lu, Zhenyu Zhang, Xudong XiaoSubjects: Materials Science (condmat.mtrlsci)
Chemical activation of the intrinsically inert basal planes of transition metal dichalcogenides (TMDs) is crucial for developing highefficiency electrocatalysts for energy technology applications. Here we report the discovery of an efficient TMDbased topological catalyst for hydrogen evolution reaction (HER), containing highdensity singleatom reactive centers on a fewlayer (7x7)PtTe2x superstructure with a Tevacancy density of x. Compared with pristine Pt(111), PtTe2, and (2x2)PtTe2x, (7x7)PtTe2x exhibits superior HER performance owing to its substantially increased density of undercoordinated Pt sites, and displays exceptional catalytic stability when operating at high current densities. Our firstprinciples calculations confirm that multiple types of undercoordinated Pt sites on (7x7)PtTe2x exhibit favorable hydrogen adsorption Gibbs free energies, and that the reactive sites can further increase their population upon increasing hydrogen coverage. Both the (2x2) and (7x7)PtTe2x are also shown to possess nontrivial band topology with robust edge states that may further facilitate HER.
 [185] arXiv:2307.12360 (replaced) [pdf, html, other]

Title: Unravelling the Mechanics of Knitted Fabrics Through Hierarchical Geometric RepresentationSubjects: Soft Condensed Matter (condmat.soft); Numerical Analysis (math.NA)
Knitting interloops onedimensional yarns into threedimensional fabrics that exhibit behaviours beyond their constitutive materials. How extensibility and anisotropy emerge from the hierarchical organisation of yarns into knitted fabrics has long been unresolved. We sought to unravel the mechanical roles of tensile mechanics, assembly and dynamics arising from the yarn level on fabric nonlinearity by developing a yarnbased dynamical model. This physically validated model captures the fundamental mechanical response of knitted fabrics, analogous to flexible metamaterials and biological fiber networks due to geometric nonlinearity within such hierarchical systems. Fabric anisotropy originates from observed yarnyarn rearrangements during alignment dynamics and is topologydependent. This yarnbased model also provides a design space of knitted fabrics to embed functionalities by varying geometric configuration and material property in instructed procedures compatible to machine manufacturing. Our hierarchical approach to build up a knitted fabrics computationally modernizes an ancient craft and represents a first step towards mechanical programmability of knitted fabrics in wide engineering applications.
 [186] arXiv:2308.07697 (replaced) [pdf, html, other]

Title: Electron states, bound to a texture in a N\'eel antiferromagnetComments: 24 pages, 18 figures, 4 appendices, 49 referencesSubjects: Strongly Correlated Electrons (condmat.strel)
We study electron states, bound to topological textures such as skyrmions and domain walls in a Néel antiferromagnet. In certain limits, we find the dependence of bound states on the geometry of the texture, and estimate the boundstate contribution to its energy. This contribution proves significant compared with the purely magnetic energy, and substantially affects the equilibrium geometry of the texture. The boundstate contribution also induces a large shift of the transition line between the modulated and the uniform phase, extending the latter.
 [187] arXiv:2308.08421 (replaced) [pdf, html, other]

Title: Transport and Energetics of Bacterial RectificationComments: 27 pages, 11 figuresSubjects: Soft Condensed Matter (condmat.soft); Statistical Mechanics (condmat.statmech); Biological Physics (physics.bioph)
Randomly moving active particles can be herded into directed motion by asymmetric geometric structures. Although such a rectification process has been extensively studied due to its fundamental, biological, and technological relevance, a comprehensive understanding of active matter rectification based on single particle dynamics remains elusive. Here, by combining experiments, simulations, and theory, we study the directed transport and energetics of swimming bacteria navigating through funnelshaped obstacles  a paradigmatic model of rectification of living active matter. We develop a microscopic parameterfree model for bacterial rectification, which quantitatively explains experimental and numerical observations and predicts the optimal geometry for the maximum rectification efficiency. Furthermore, we quantify the degree of time irreversibility and measure the extractable work associated with bacterial rectification. Our study provides quantitative solutions to longstanding questions on bacterial rectification and establishes a generic relationship between time irreversibility, particle fluxes, and extractable work, shedding light on the energetics of nonequilibrium rectification processes in living systems.
 [188] arXiv:2308.12778 (replaced) [pdf, html, other]

Title: Realtime milliKelvin thermometry in a semiconductor qubit architectureVictor Champain, Vivien Schmitt, Benoit Bertrand, Heimanu Niebojewski, Romain Maurand, Xavier Jehl, Clemens Winkelmann, Silvano De Franceschi, Boris BrunComments: 7 pages 4 figures (supp. mat. 6 pages and 5 figures)Journalref: Phys. Rev. Applied 21, 064039 (2024)Subjects: Mesoscale and Nanoscale Physics (condmat.meshall)
We report local timeresolved thermometry in a silicon nanowire quantum dot device designed to host a linear array of spin qubits. Using two alternative measurement schemes based on rf reflectometry, we are able to probe either local electron or phonon temperatures with $\mu$sscale time resolution and a noise equivalent temperature of $3$ $\rm mK/\sqrt{\rm Hz}$. Following the application of short microwave pulses, causing local periodic heating, timedependent thermometry can track the dynamics of thermal excitation and relaxation, revealing clearly different characteristic time scales. This work opens important prospects to investigate the outofequilibrium thermal properties of semiconductor quantum electronic devices operating at very low temperature. In particular, it may provide a powerful handle to understand heating effects recently observed in semiconductor spinqubit systems.
 [189] arXiv:2309.02316 (replaced) [pdf, html, other]

Title: Landau Theory of Barocaloric Plastic CrystalsComments: 24 pages, 5 figuresJournalref: J. Phys. Energy 6 035003 (2024)Subjects: Materials Science (condmat.mtrlsci)
We present a minimal Landau theory of plastictocrystal phase transitions in which the key components are a multipolemoment order parameter that describes the orientational ordering of the constituent molecules, coupling between such order parameter and elastic strains, and thermal expansion. We illustrate the theory with the simplest nontrivial model in which the orientational ordering is described by a quadrupole moment, and use such model to calculate barocaloric effects in plastic crystals that are driven by hydrostatic pressure. The model captures characteristic features of plastictocrystal phase transitions, namely, large changes in volume and entropy at the transition, as well as the linear dependence of the transition temperature with pressure. We identify temperature regions in the barocaloric response associated with the individual plastic and crystal phases, and those involving the phase transition. Our model is in overall agreement with previous experiments in powdered samples of fullerite C$_{60}$, and predicts peak isothermal entropy changes of $\sim90 \,{\rm J K^{1} kg^{1}}$ and peak adiabatic temperature changes of $\sim35 \,{\rm K}$ under $0.60\,$GPa at $265\,$K in fullerite single crystals.
 [190] arXiv:2310.06476 (replaced) [pdf, html, other]

Title: Accounting for localized deformation: a simple computation of true stress in micropillar compression experimentsComments: arXiv admin note: text overlap with arXiv:2012.12780Subjects: Materials Science (condmat.mtrlsci); Mesoscale and Nanoscale Physics (condmat.meshall)
Compression experiments are widely used to study the mechanical properties of materials at micro and nanoscale. However, the conventional engineering stress measurement method used in these experiments neglects to account for the alterations in the material's shape during loading. This can lead to inaccurate stress values and potentially misleading conclusions about the material's mechanical behavior especially in the case of localized deformation. To address this issue, we present a method for calculating true stress in cases of localized plastic deformation commonly encountered in experimental settings: (i) a single band and (ii) two bands oriented in arbitrary directions with respect to the vertical axis of the pillar (either in the same or opposite directions). Our simple analytic formulas can be applied to homogeneous and isotropic materials and crystals, requiring only standard data (displacementforce curve, aspect ratio, shear band angle and elastic strain limit) obtained from experimental results and eliminating the need for finite element computations. Our approach provides a more precise interpretation of experimental results and can serve as a valuable and simple tool in material design and characterization.
 [191] arXiv:2310.09082 (replaced) [pdf, html, other]

Title: From Maximum of Intervisit Times to Starving Random WalksComments: 6 pages, 3 figures + 16 pages, 11 figuresJournalref: Phys. Rev. Lett. 132, 127101 (2024)Subjects: Statistical Mechanics (condmat.statmech); Mathematical Physics (mathph); Data Analysis, Statistics and Probability (physics.dataan)
Very recently, a fundamental observable has been introduced and analyzed to quantify the exploration of random walks: the time $\tau_k$ required for a random walk to find a site that it never visited previously, when the walk has already visited $k$ distinct sites. Here, we tackle the natural issue of the statistics of $M_n$, the longest duration out of $\tau_0,\dots,\tau_{n1}$. This problem belongs to the active field of extreme value statistics, with the difficulty that the random variables $\tau_k$ are both correlated and nonidentically distributed. Beyond this fundamental aspect, we show that the asymptotic determination of the statistics of $M_n$ finds explicit applications in foraging theory and allows us to solve the open $d$dimensional starving random walk problem, in which each site of a lattice initially contains one food unit, consumed upon visit by the random walker, which can travel $\mathcal{S}$ steps without food before starving. Processes of diverse nature, including regular diffusion, anomalous diffusion, and diffusion in disordered media and fractals, share common properties within the same universality classes.
 [192] arXiv:2311.01545 (replaced) [pdf, other]

Title: Quantifying chemical shortrange order in metallic alloysComments: 8 pages, 4 figuresSubjects: Materials Science (condmat.mtrlsci)
Metallic alloys often form phases  known as solid solutions  in which chemical elements are spread out on the same crystal lattice in an almost random manner. The tendency of certain chemical motifs to be more common than others is known as chemical shortrange order (SRO) and it has received substantial consideration in alloys with multiple chemical elements present in large concentrations due to their extreme configurational complexity (e.g., highentropy alloys). Shortrange order renders solid solutions "slightly less random than completely random", which is a physically intuitive picture, but not easily quantifiable due to the sheer number of possible chemical motifs and their subtle spatial distribution on the lattice. Here we present a multiscale method to predict and quantify the SRO state of an alloy with atomic resolution, incorporating machine learning techniques to bridge the gap between electronicstructure calculations and the characteristic length scale of SRO. The result is an approach capable of predicting SRO length scale in agreement with experimental measurements while comprehensively correlating SRO with fundamental quantities such as local lattice distortions. This work advances the quantitative understanding of solidsolution phases, paving the way for SRO rigorous incorporation into predictive mechanical and thermodynamic models.
 [193] arXiv:2311.15440 (replaced) [pdf, html, other]

Title: Exact transport coefficients from the inelastic rough Maxwell model of a granular gasComments: 32 pages, 4 figures (15 panels); v2: several improvements in the text. Includes a correction to Eqs. (57a) and (57b), see this https URLJournalref: J. Stat. Phys. 191, 54 (2024)Subjects: Soft Condensed Matter (condmat.soft); Statistical Mechanics (condmat.statmech)
Granular gases demand models capable of capturing their distinct characteristics. The widely employed inelastic hardsphere model (IHSM) introduces complexities that are compounded when incorporating realistic features like surface roughness and rotational degrees of freedom, resulting in the more intricate inelastic rough hardsphere model (IRHSM). This paper focuses on the inelastic rough Maxwell model (IRMM), presenting a more tractable alternative to the IRHSM and enabling exact solutions. Building on the foundation of the inelastic Maxwell model (IMM) applied to granular gases, the IRMM extends the mathematical representation to encompass surface roughness and rotational degrees of freedom. The primary objective is to provide exact expressions for the NavierStokesFourier transport coefficients within the IRMM, including the shear and bulk viscosities, the thermal and diffusive heat conductivities, and the coolingrate transport coefficient. In contrast to earlier approximations in the IRHSM, our study unveils inherent couplings, such as shear viscosity to spin viscosity and heat conductivities to counterparts associated with a torquevorticity vector. These exact findings provide valuable insights into refining the Sonine approximation applied to the IRHSM, contributing to a deeper understanding of the transport properties in granular gases with realistic features.
 [194] arXiv:2311.15779 (replaced) [pdf, html, other]

Title: Scale invariance of a spherical unitary Fermi gasComments: 15 pages and 10 figursJournalref: Phys. Rev. Lett. 132, 243403 (2024), Editors' SuggestionSubjects: Quantum Gases (condmat.quantgas); Atomic Physics (physics.atomph)
A unitary Fermi gas in an isotropic harmonic trap is predicted to show scale and conformal symmetry that have important consequences in its thermodynamic and dynamical properties. By experimentally realizing a unitary Fermi gas in an isotropic harmonic trap, we demonstrate its universal expansion dynamics along each direction and at different temperatures. We show that as a consequence of SO(2,1) symmetry, the measured release energy is equal to that of the trapping energy. We further observe the breathing mode with an oscillation frequency twice the trapping frequency and a small damping rate, providing the evidence of SO(2,1) symmetry. In addition, away from resonance when scale invariance is broken, we determine the effective exponent $\gamma$ that relates the chemical potential and average density along the BECBCS crossover, which qualitatively agrees with the mean field predictions. This work opens the possibility of studying nonequilibrium dynamics in a conformal invariant system in the future.
 [195] arXiv:2311.16748 (replaced) [pdf, html, other]

Title: Heat Pulses in Electron Quantum OpticsComments: 7+5 pages, 4 figuresJournalref: Phys. Rev. Lett. 132, 256301 (2024)Subjects: Mesoscale and Nanoscale Physics (condmat.meshall); Quantum Physics (quantph)
Electron quantum optics aims to realize ideas from the quantum theory of light with the role of photons being played by charge pulses in electronic conductors. Experimentally, the charge pulses are excited by timedependent voltages, however, one could also generate heat pulses by heating and cooling an electrode. Here, we explore this intriguing idea by formulating a Floquet scattering theory of heat pulses in mesoscopic conductors. The adiabatic emission of heat pulses leads to a heat current that in linear response is given by the thermal conductance quantum. However, we also find a highfrequency component, which ensures that the fluctuationdissipation theorem for heat currents, whose validity has been debated, is fulfilled. The heat pulses are uncharged, and we probe their electronhole content by evaluating the partition noise in the outputs of a quantum point contact. We also employ a HongOuMandel setup to examine if the pulses bunch or antibunch. Finally, to generate an electric current, we use a MachZehnder interferometer that breaks the electronhole symmetry and thereby enables a thermoelectric effect. Our work paves the way for systematic investigations of heat pulses in mesoscopic conductors, and it may stimulate future experiments.
 [196] arXiv:2311.18682 (replaced) [pdf, html, other]

Title: Electronic and spectral properties of Ge1xSnx quantum dots: an atomistic studySubjects: Mesoscale and Nanoscale Physics (condmat.meshall)
In this paper, we study theoretically the electron and spectral properties of Ge1xSnx systems, including alloys, cubic and spherical quantum dots. The singleparticle electron and hole states are calculated within the sp3d5s* tightbinding approach and used in further modeling of the optical properties. We systematically study the interplay of Sndriven indirectdirect bandgap transition and the quantum confinement effect in systems of reduced dimensionality. We demonstrate the regime of sizes and composition, where the ground state in Ge1xSnx quantum dot is optically active. Finally, we calculate absorbance spectra in experimentallyrelevant colloidal quantum dots and demonstrate a satisfactory agreement with experimental data.
 [197] arXiv:2312.09253 (replaced) [pdf, html, other]

Title: Bayesian Optimization for Robust State Preparation in Quantum ManyBody SystemsComments: 6 + 6 pagesSubjects: Quantum Gases (condmat.quantgas); Quantum Physics (quantph)
New generations of ultracoldatom experiments are continually raising the demand for efficient solutions to optimal control problems. Here, we apply Bayesian optimization to improve a statepreparation protocol recently implemented in an ultracoldatom system to realize a twoparticle fractional quantum Hall state. Compared to manual ramp design, we demonstrate the superior performance of our optimization approach in a numerical simulation  resulting in a protocol that is 10x faster at the same fidelity, even when taking into account experimentally realistic levels of disorder in the system. We extensively analyze and discuss questions of robustness and the relationship between numerical simulation and experimental realization, and how to make the best use of the surrogate model trained during optimization. We find that numerical simulation can be expected to substantially reduce the number of experiments that need to be performed with even the most basic transfer learning techniques. The proposed protocol and workflow will pave the way toward the realization of more complex manybody quantum states in experiments.
 [198] arXiv:2312.14011 (replaced) [pdf, html, other]

Title: Control of threshold voltages in Si/SiGe quantum devices via optical illuminationM. A. Wolfe, Brighton X. Coe, Justin S. Edwards, Tyler J. Kovach, Thomas McJunkin, Benjamin Harpt, D. E. Savage, M. G. Lagally, R. McDermott, Mark Friesen, Shimon Kolkowitz, M. A. ErikssonComments: 8 pages, 6 figuresSubjects: Mesoscale and Nanoscale Physics (condmat.meshall); Quantum Physics (quantph)
Optical illumination of quantumdot qubit devices at cryogenic temperatures, while not well studied, is often used to recover operating conditions after undesired shocking events or charge injection. Here, we demonstrate systematic threshold voltage shifts in a dopantfree, Si/SiGe field effect transistor using a near infrared (780 nm) laser diode. We find that illumination under an applied gate voltage can be used to set a specific, stable, and reproducible threshold voltage that, over a wide range in gate bias, is equal to that gate bias. Outside this range, the threshold voltage can still be tuned, although the resulting threshold voltage is no longer equal to the applied gate bias during illumination. We present a simple and intuitive model that provides a mechanism for the tunability in gate bias. The model presented also explains why cryogenic illumination is successful at resetting quantum dot qubit devices after undesired charging events.
 [199] arXiv:2312.14885 (replaced) [pdf, html, other]

Title: Full Record Statistics of 1d Random WalksComments: 16 pages, 5 figuresJournalref: Phys. Rev. E 109, 064101 (2024)Subjects: Statistical Mechanics (condmat.statmech); Mathematical Physics (mathph); Data Analysis, Statistics and Probability (physics.dataan)
We develop a comprehensive framework for analyzing full record statistics, covering record counts $M(t_1), M(t_2), \ldots$, and their corresponding attainment times $T_{M(t_1)}, T_{M(t_2)}, \ldots$, as well as the intervals until the next record. From this multipletime distribution, we derive general expressions for various observables related to record dynamics, including the conditional number of records given the number observed at a previous time and the conditional time required to reach the current record, given the occurrence time of the previous one. Our formalism is exemplified by a variety of stochastic processes, including biased nearestneighbor random walks, asymmetric runandtumble dynamics, and random walks with stochastic resetting.
 [200] arXiv:2312.17744 (replaced) [pdf, html, other]

Title: Universality classes for purification in nonunitary quantum processesComments: 22 pages, 13 figures, many improvements for clarity in v2, inc extended introductory text, new figures and one more technical appendixSubjects: Statistical Mechanics (condmat.statmech); Disordered Systems and Neural Networks (condmat.disnn); Strongly Correlated Electrons (condmat.strel)
We consider universal aspects of two problems: (i) the slow purification of a large number of qubits by repeated quantum measurements, and (ii) the singular value structure of a product ${m_t m_{t1}\ldots m_1}$ of many large random matrices. Each kind of process is associated with the decay of natural measures of entropy as a function of time or of the number of matrices in the product. We argue that, for a broad class of models, each process is described by universal scaling forms for purification, and that (i) and (ii) represent distinct ``universality classes'' with distinct scaling functions. Using the replica trick, these universality classes correspond to onedimensional effective statistical mechanics models for a gas of ``kinks'', representing domain walls between elements of the permutation group. (This is an instructive lowdimensional limit of the effective statistical mechanics models for random circuits and tensor networks.) These results apply to longtime purification in spatially local monitored circuit models on the entangled side of the measurement phase transition.
 [201] arXiv:2401.04967 (replaced) [pdf, html, other]

Title: Electrical NonHermitian Control of Topological Magnon Spin TransportSubjects: Mesoscale and Nanoscale Physics (condmat.meshall)
Magnonic topological phases realize chiral edge spin waves that are protected against backscattering, potentially enabling highly efficient spin transport. Here we show that the spin transport through these magnonic chiral edge states can be electrically manipulated by nonHermitian control. We consider the paradigmatic magnon Haldane model and show that it is transformed into an effective nonHermitian magnon Chern insulator by including a sublatticedependent spinorbit torque. In linear spinwave theory, this electrically induced torque reduces the damping of the chiral edge magnons along certain edge directions, leading to an enhancement of the spinwave amplitude. This prediction is confirmed by numerical simulations based on the LandauLifshitzGilbert equation. For a spinwave transport setup, in which magnons are excited by a microwave field and detected with a normal metal conductor, we find that the magnon amplification is remarkably robust against disorder, establishing nonHermitian control as a promising avenue for topological magnonics.
 [202] arXiv:2401.08627 (replaced) [pdf, html, other]

Title: Predicting and Interpreting Energy Barriers of Metallic Glasses with Graph Neural NetworksComments: Accepted at ICML 2024Subjects: Disordered Systems and Neural Networks (condmat.disnn); Materials Science (condmat.mtrlsci); Machine Learning (cs.LG)
Metallic Glasses (MGs) are widely used materials that are stronger than steel while being shapeable as plastic. While understanding the structureproperty relationship of MGs remains a challenge in materials science, studying their energy barriers (EBs) as an intermediary step shows promise. In this work, we utilize Graph Neural Networks (GNNs) to model MGs and study EBs. We contribute a new dataset for EB prediction and a novel Symmetrized GNN (SymGNN) model that is E(3)invariant in expectation. SymGNN handles invariance by aggregating over orthogonal transformations of the graph structure. When applied to EB prediction, SymGNN are more accurate than molecular dynamics (MD) localsampling methods and other machinelearning models. Compared to precise MD simulations, SymGNN reduces the inference time on new MGs from roughly 41 days to less than one second. We apply explanation algorithms to reveal the relationship between structures and EBs. The structures that we identify through explanations match the mediumrange order (MRO) hypothesis and possess unique topological properties. Our work enables effective prediction and interpretation of MG EBs, bolstering material science research.
 [203] arXiv:2401.11919 (replaced) [pdf, html, other]

Title: Thermodynamic work of partial resettingSubjects: Statistical Mechanics (condmat.statmech); Soft Condensed Matter (condmat.soft)
Partial resetting, whereby a state variable $x(t)$ is reset at random times to a value $a x (t)$, $0\leq a \leq 1$, generalizes conventional resetting by introducing the resetting strength $a$ as a parameter. Partial resetting generates a broad family of nonequilibrium steady states (NESS) that interpolates between the conventional NESS at strong resetting ($a=0$) and a Gaussian distribution at weak resetting ($a \to 1$). Here, such resetting processes are studied from a thermodynamic perspective, and the mean cost associated with maintaining such NESS are derived. The resetting phase of the dynamics is implemented by a resetting potential $\Phi(x)$ that mediates the resets in finite time. By working in an ensemble of trajectories with a fixed number of resets, we study both the steadystate properties of the propagator and its moments. The thermodynamic work needed to sustain the resulting NESS is then investigated. We find that different resetting traps can give rise to rates of work with widely different dependencies on the resetting strength $a$. Surprisingly, in the case of resets mediated by a harmonic trap with otherwise free diffusive motion, the asymptotic rate of work is insensitive to the value of $a$. For general anharmonic traps, the asymptotic rate of work can be either increasing or decreasing as a function of the strength $a$, depending on the degree of anharmonicity. Counter to intuition, the rate of work can therefore in some cases increase as the resetting becomes weaker $(a\to 1)$ although the work vanishes at $a=1$. Work in the presence of a background potential is also considered. Numerical simulations confirm our findings.
 [204] arXiv:2402.01973 (replaced) [pdf, html, other]

Title: Refined bounds on energy harvesting from anisotropic fluctuationsComments: 6 pages, 4 figuresSubjects: Statistical Mechanics (condmat.statmech)
We consider overdamped Brownian particles with two degrees of freedom (DoF) that are confined in a timevarying quadratic potential and are in simultaneous contact with heat baths of different temperatures along the respective DoF. The anisotropy in thermal fluctuations can be used to extract work by suitably manipulating the confining potential. The question of what the maximal amount of work that can be extracted is has been raised in recent work, and has been computed under the simplifying assumption that the entropy of the distribution of particles (thermodynamic states) remains constant throughout a thermodynamic cycle. Indeed, it was shown that the maximal amount of work that can be extracted amounts to solving an isoperimetric problem, where the 2Wasserstein length traversed by thermodynamic states quantifies dissipation that can be traded off against an area integral that quantifies work drawn out of the thermal anisotropy. Here, we remove the simplifying assumption on constancy of entropy. We show that the work drawn can be computed similarly to the case where the entropy is kept constant while the dissipation can be reduced by suitably tilting the thermodynamic cycle in a thermodynamic space with one additional dimension. Optimal cycles can be locally approximated by solutions to an isoperimetric problem in a tilted lowerdimensional subspace.
 [205] arXiv:2402.10031 (replaced) [pdf, html, other]

Title: Tomographic Imaging of Orbital Vortex Lines in ThreeDimensional Momentum SpaceT. Figgemeier, M. Ünzelmann, P. Eck, J. Schusser, L. Crippa, J. N. Neu, B. Geldiyev, P. Kagerer, J. Buck, M. Kalläne, M. Hoesch, K. Rossnagel, T. Siegrist, L.K. Lim, R. Moessner, G. Sangiovanni, D. Di Sante, F. Reinert, H. BentmannSubjects: Strongly Correlated Electrons (condmat.strel); Mesoscale and Nanoscale Physics (condmat.meshall); Optics (physics.optics)
We report the experimental discovery of orbital vortex lines in the threedimensional (3D) band structure of a topological semimetal. Combining linear and circular dichroism in soft xray angleresolved photoemission (SXARPES) with firstprinciples theory, we image the winding of atomic orbital angular momentum, thereby revealing  and determining the location of  lines of vorticity in full 3D momentum space. Our observation of momentumspace vortex lines with quantized winding number establishes an analogue to realspace quantum vortices, for instance, in typeII superconductors and certain noncollinear magnets. These results establish multimodal dichroism in SXARPES as an approach to trace 3D orbital textures. Our present findings particularly constitute the first imaging of nontrivial quantumphase winding at line nodes and may pave the way to new orbitronic phenomena in quantum materials
 [206] arXiv:2403.06040 (replaced) [pdf, html, other]

Title: Implementation and characterization of the dice lattice in the electron quantum simulatorComments: 10 pages, 9 figuresSubjects: Mesoscale and Nanoscale Physics (condmat.meshall); Quantum Physics (quantph)
Materials featuring touching points, localized states, and flat bands are of great interest in condensed matter and artificial systems due to their implications in topology, quantum geometry, superconductivity, and interactions. In this theoretical study, we propose the experimental realization of the dice lattice with adjustable parameters by arranging carbon monoxide molecules on a twodimensional electron system at a (111) copper surface. First, we develop a theoretical framework to obtain the spectral properties within a nearly free electron approximation and then compare them with tightbinding calculations. Our investigation reveals that the high mobility of Shockley state electrons enables an accurate theoretical description of the artificial lattice using a nextnearestneighbor tightbinding model, resulting in the emergence of a touching point, a quasiflat band, and localized lattice site behavior in the local density of states. Additionally, we present theoretical results for a longwavelength lowenergy model that accounts for nextnearestneighbor hopping terms. Furthermore, we theoretically examine the model's behavior under an external magnetic field by employing Peierl's substitution, a commonly used technique in theoretical physics to incorporate magnetic fields into lattice models. Our theoretical findings suggest that, owing to the exceptional electron mobility, the highly degenerate eigenenergy associated with the AharonovBohm caging mechanism may not manifest in the proposed experiment.
 [207] arXiv:2403.06226 (replaced) [pdf, html, other]

Title: Drag on Cylinders Moving in Superfluid 3HeB as the Dimension Spans the Coherence LengthComments: Paper submitted to the Journal of Low Temperature Physics memorial issue in honour of A.F. AndreevSubjects: Mesoscale and Nanoscale Physics (condmat.meshall)
Vibrating probes when immersed in a fluid can provide powerful tools for characterising the surrounding medium. In superfluid 3HeB, a condensate of Cooper pairs, the dissipation arising from the scattering of quasiparticle excitations from a mechanical oscillator provides the basis of extremely sensitive thermometry and bolometry at submillikelvin temperatures. The unique properties of the Andreev reflection process in this condensate also assist by providing a significantly enhanced dissipation. While existing models for such damping on an oscillating cylinder have been verified experimentally, they are valid only for flows with scales much greater than the coherence length of 3He, which is of the order of a hundred nanometres. With our increasing proficiency in fabricating nanosized oscillators which can be readily used in this superfluid there is a pressing need for the development of new models that account for the modification of the flow around these smaller oscillators. Here we report preliminary results on measurements of the damping in superfluid 3HeB of a range of cylindrical nanosized oscillators with radii comparable to the coherence length, and outline a model for calculating the associated drag.
 [208] arXiv:2403.06827 (replaced) [pdf, html, other]

Title: Orbital relaxation length from firstprinciples scattering calculationsComments: 6 pages, 6 figuresJournalref: Physical Review B 109, 214427 (2024)Subjects: Mesoscale and Nanoscale Physics (condmat.meshall)
The orbital Hall effect generates a current of orbital angular momentum perpendicular to a charge current. Experiments suggest that this orbital current decays on a long length scale that is of the order of the spin flip diffusion length or longer. We examine this suggestion using firstprinciples quantum mechanical scattering calculations to study the decay of orbital currents injected from an orbitallypolarized lead into thermally disordered bulk systems of selected transition metals. We find that the decay occurs over only a few atomic layers. On this length scale the orbital current may be converted into a spin current if the spin Hall angle is sufficiently large, as for Pt. In Cu, Cr and V with small spin Hall angles, the conversion into a spin current is negligible in the bulk and significant conversion only occurs at interfaces.
 [209] arXiv:2403.07055 (replaced) [pdf, html, other]

Title: Orbital angular momentum of Bloch electrons: equilibrium formulation, magnetoelectric phenomena, and the orbital Hall effectComments: 25 pages, 8 figuresSubjects: Mesoscale and Nanoscale Physics (condmat.meshall)
The investigation of orbital angular momentum (OAM) of delocalised Bloch electrons has advanced our understanding of magnetic, transport, and optical phenomena in crystals, drawing widespread interest across various materials science domains, from metals and semiconductors to topological and magnetic materials. Here, we review OAM dynamics in depth, focusing on key concepts and nonequilibrium systems, and laying the groundwork for the thriving field of {\it orbitronics}. We review briefly the conventional understanding of the equilibrium OAM based on the modern theory of orbital magnetisation. Following this, we explore recent theoretical and experimental developments in outofequilibrium systems. We focus on the generation of an OAM density via the orbital magnetoelectric, or Edelstein effect, the generation of an OAM current via the orbital Hall effect, the orbital torque resulting from them, along with their reciprocal nonequilibrium counterparts  the inverse orbital Edelstein and inverse orbital Hall effects, as well as OAM conservation. We discuss the most salient achievements and the most pressing challenges in this rapidly evolving field, and in closing we highlight the future prospects of {\it orbitronics}.
 [210] arXiv:2403.08432 (replaced) [pdf, html, other]

Title: Modelling of initially stressed solids: structure of the energy density in the incompressible limitSubjects: Soft Condensed Matter (condmat.soft)
This study addresses the modelling of elastic bodies, particularly when the relaxed configuration is unknown or nonexistent. We adopt the theory of initially stressed materials, incorporating the deformation gradient and stress state of the reference configuration (initial stress tensor) into the response function. We show that for the theory to be applicable, the response function of the relaxed material is invertible up to an element of the material symmetry group. Additionally, we establish that commonly imposed constitutive restrictions, namely the initial stress compatibility condition and initial stress reference independence, naturally arise when assuming an initial stress generated solely from elastic distortion. The paper delves into modelling aspects concerning incompressible materials, showcasing the expressibility of strain energy density as a function of the deviatoric part of the initial stress tensor and the isochoric part of the deformation gradient. This not only reduces the number of independent invariants in the energy functional, but also enhances numerical robustness in finite element simulations. The findings of this research hold significant implications for modelling materials with initial stress, extending potential applications to areas such as mechanobiology, soft robotics, and 4D printing.
 [211] arXiv:2403.10743 (replaced) [pdf, html, other]

Title: Nonunique detailed constructions of CurzonAhlborn cycle on thermodynamic planeComments: 14 pages, 4 figuresSubjects: Statistical Mechanics (condmat.statmech)
The CurzonAhlborn (CA) cycle is a paradigmatic model of endoreversible heat engines, which yields the socalled CA efficiency as the efficiency at maximum power. Due to the arbitrariness of the relationship between the steady temperature and the time taken for the isothermal process of the CA cycle, the constructions of the CA cycle on the thermodynamic plane are not unique. Here, we give some of the detailed constructions of the CA cycle on the thermodynamic plane, using an ideal gas as a working substance. It is shown that these constructions are equal to each other in the maximum power regime in the sense that they achieve the best tradeoff between the work and the inverse cycletime, known as the Pareto front in multiobjective optimization problems.
 [212] arXiv:2403.10975 (replaced) [pdf, html, other]

Title: Nonequilibrium tricritical behaviour in anisotropic XY ferromagnet driven by elliptically polarised propagating magnetic field waveComments: Revised version 15 pages plain Latex and 14 captioned pdf figuresSubjects: Statistical Mechanics (condmat.statmech)
Three dimensional anisotropic XY ferromagnet driven by elliptically polarized propagating magnetic field wave has been extensively investigated by Monte Carlo simulation with Metropolis single spin flip algorithm. Both the effects of the bilinear exchange type and the single site anisotropies are thoroughly investigated. The time average magnetisation (over the complete cycle of the elliptically polarized propagating magnetic field wave) components play the role of dynamic order parameter. For fixed set of values of the strength of anisotropy and the field amplitudes, the system has been found to get dynamically ordered at a pseudocritical temperature. The pseudocritical temperature of such dynamic nonequilibrium phase transition has been found to depend on both the strength of anisotropy and the amplitudes of the elliptically polarized propagating magnetic field wave. A comprehensive phase diagram is represented here in the form of image plot of the pseudocritical temperature in the plane formed by the strength of anisotropy and field amplitudes. Interestingly, this nonequilibrium phase transition has been found discontinuous (first order) for higher values of the field amplitude and lower values of the anisotropy. On the other hand, the continuous (second order) transition has been noticed for lower values of the field amplitude and higher values of the anisotropy.
 [213] arXiv:2403.12758 (replaced) [pdf, html, other]

Title: Strongcoupling critical behavior in threedimensional lattice Abelian gauge models with charged $N$component scalar fields and $SO(N)$ symmetryComments: 12 pages, 11 pdf figures, some references added. arXiv admin note: text overlap with arXiv:2310.08504Journalref: Phys. Rev. E 109, 064142 (2024)Subjects: Statistical Mechanics (condmat.statmech); High Energy Physics  Lattice (heplat)
We consider a threedimensional lattice Abelian Higgs gauge model for a charged $N$component scalar field ${\phi}$, which is invariant under $SO(N)$ global transformations for generic values of the parameters. We focus on the strongcoupling regime, in which the kinetic Hamiltonian term for the gauge field is a small perturbation, which is irrelevant for the critical behavior. The Hamiltonian depends on a parameter $v$ which determines the global symmetry of the model and the symmetry of the lowtemperature phases. We present renormalizationgroup predictions, based on a LandauGinzburgWilson effective description that relies on the identification of the appropriate order parameter and on the symmetrybreaking patterns that occur at the strongcoupling phase transitions. For $v=0$, the global symmetry group of the model is $SU(N)$; the corresponding model may undergo continuous transitions only for $N=2$. For $v\not=0$, i.e., in the $SO(N)$ symmetric case, continuous transitions (in the Heisenberg universality class) are possible also for $N=3$ and 4. We perform Monte Carlo simulations for $N=2,3,4,6$, to verify the renormalizationgroup predictions. Finitesize scaling analyses of the numerical data are in full agreement.
 [214] arXiv:2403.14482 (replaced) [pdf, html, other]

Title: Assessing exchangecorrelation functionals for heterogeneous catalysis of nitrogen speciesComments: 44 pages, 20 figures. Figure 4 (MIL125) data is changed. Relevant contents (texts, tables, figures, SI) are changed. VASP data is shared with accessible Zenodo linkSubjects: Materials Science (condmat.mtrlsci); Chemical Physics (physics.chemph)
Increasing interest in sustainable synthesis of ammonia, nitrates, and urea has led to an increase in studies of catalytic conversion between nitrogencontaining compounds using heterogeneous catalysts. Density functional theory (DFT) is commonly employed to obtain molecularscale insight into these reactions, but there have been relatively few assessments of the exchangecorrelation functionals that are best suited for heterogeneous catalysis of nitrogen compounds. Here, we assess a range of functionals ranging from the generalized gradient approximation (GGA) to the random phase approximation (RPA) for the formation energies of gasphase nitrogen species, the lattice constants of representative solids from several common classes of catalysts (metals, oxides, and metalorganic frameworks (MOFs)), and the adsorption energies of a range of nitrogencontaining intermediates on these materials. The results reveal that the choice of exchangecorrelation functional and van der Waals correction can have a surprisingly large effect and that increasing the level of theory does not always improve the accuracy for nitrogencontaining compounds. This suggests that the selection of functionals should be carefully evaluated on the basis of the specific reaction and material being studied.
 [215] arXiv:2403.15680 (replaced) [pdf, html, other]

Title: Magnetic parity violation and paritytimereversalsymmetric magnetsComments: Invited topical review in Journal of Physics: Condensed Matter, 55 pagesJournalref: J. Phys.: Condens. Matter 36, 373001 (2024)Subjects: Materials Science (condmat.mtrlsci)
Paritytimereversal symmetry ($\mathcal{PT}$ symmetry), a symmetry for the combined operations of space inversion ($\mathcal{P}$) and time reversal ($\mathcal{T}$), is a fundamental concept of physics and characterizes the functionality of materials as well as $\mathcal{P}$ and $\mathcal{T}$ symmetries. In particular, the $\mathcal{PT}$symmetric systems can be found in the centrosymmetric crystals undergoing the parityviolating magnetic order which we call the oddparity magnetic multipole order. While this spontaneous order leaves $\mathcal{PT}$ symmetry intact, the simultaneous violation of $\mathcal{P}$ and $\mathcal{T}$ symmetries gives rise to various emergent responses that are qualitatively different from those allowed by the nonmagnetic $\mathcal{P}$symmetry breaking or by the ferromagnetic order. In this review, we introduce candidates hosting the intriguing spontaneous order and overview the characteristic physical responses. Various offdiagonal and/or nonreciprocal responses are identified, which are closely related to the unusual electronic structures such as hidden spinmomentum locking and asymmetric band dispersion.
 [216] arXiv:2404.01311 (replaced) [pdf, other]

Title: Colossal Seebeck coefficient of thermoelectric material calculated by space charge effect, and phonon drag backgroundSubjects: Materials Science (condmat.mtrlsci)
Recently colossal Seebeck coefficient ($S$) has found in the several thermoelectric (TE) materials. We present colossal $S$ and large thermal electron motivate force (EMF) reproduced by space charge (SC) model, introducing multiDebye lengths within grain boundaries (GBs) of TE materials with phonon drag (PD) effect accompanying with electron by electronphonon interaction. In addition to $S$, the polarity reversal was also reproduced by transfer process with inner bias around SP generated from thermal EMF. Colossal $S$ and EMF for TE material were reproduced by inner SC model as a functions of averaged multiDebye length within GBs.
 [217] arXiv:2404.02219 (replaced) [pdf, html, other]

Title: Spin and bondcharge excitation spectra in correlated electron systems near antiferromagnetic phaseComments: 59 pages, 29 figuresJournalref: Phy. Rev. B 109, 245127 (2024)Subjects: Strongly Correlated Electrons (condmat.strel); Superconductivity (condmat.suprcon)
Magnetic and bondcharge interactions can arise from the same microscopic interaction. Motivated by this observation, we compute magnetic and bondcharge excitation spectra on an equal footing by introducing a simple effective model on a square lattice, which describes antiferromagnetic and dwave superconducting phases around halffilling on the electrondoped side. The magnetic excitation spectrum Im chi(q, omega) has strong weight around q=(pi, pi) in low energy and its intensity map exhibits a penciltiplike shape in qomega space. Around q=(0,0) magnetic excitations show a steep dispersion toward the (pi, pi) and (pi,0) directions, which is very similar to a spinwave dispersion although the system is nonmagnetic. Bondcharge excitations are characterized by four different symmetries and studied for all possible couplings. Bondcharge fluctuations with three different symmetries have large spectral weight around q=(pi, pi) in a relatively lowenergy region and extend widely more than the magnetic excitation spectrum. The dwave symmetry of bondcharge excitations also has sizable spectral weight along the direction (pi/2, pi/2)(0, 0)(pi/2, 0) in a lowenergy region and exhibits softening around q approx (0.5 pi, 0), whereas no such softening is present in the other symmetries. These results capture the essential features observed in electrondoped cuprates and may motivate an experimental test of bondcharge excitations around q=(pi, pi) on top of the strong magnetic excitations there as well as additional softening in the dwave channel in the (pi, pi)(pi/2, pi/2) region at low temperatures near the magnetic phase. We extend the present analysis to the holedoped side and highlight a contrast to the electrondoped side, which includes incommensurate correlations, electronic nematic correlations, and spin and bondcharge resonance modes in the superconducting state.
 [218] arXiv:2404.03416 (replaced) [pdf, html, other]

Title: Magnetic anisotropy of L1$_0$ FeNi (001), (010), and (111) ultrathin films: A firstprinciples studySubjects: Materials Science (condmat.mtrlsci); Mesoscale and Nanoscale Physics (condmat.meshall)
In previous experiments, thin films of L1$\mathrm{_0}$ FeNi with different surfaces, including (001), (110) and (111), were produced and studied. Each surface defines a different alignment of the crystallographic tetragonal axis with respect to the film's plane, resulting in different magnetic anisotropies. In this study, we use density functional theory calculations to examine three series of L1$\mathrm{_0}$ FeNi films with surfaces (001), (010), and (111), and with thicknesses ranging from 0.5 to 3 nm (from 4 to 16 atomic monolayers). Our results show that films (001) have perpendicular magnetic anisotropy, while (010) favor inplane magnetization, with a clear preference for the tetragonal axis [001]. We propose calling this type of inplane anisotropy fixed in plane. A film with surface (111) and a thickness of four atomic monolayers has the magnetization easy axis almost perpendicular to the plane of the film. As the thickness of the (111) film increases, the direction of magnetization rotates towards a tetragonal axis [001], positioned at an angle of about 45$^{o}$ to the plane of the film. Furthermore, the magnetic moment of ultrathin films increases by a maximum of 5%, and the most significant changes in spin and orbital magnetic moments occur at a depth of about three nearsurface atomic monolayers. The presented results could be useful for experimental efforts to synthesize ultrathin L1$\mathrm{_0}$ FeNi films with different surfaces. Ultrathin L1$\mathrm{_0}$ FeNi films with varying magnetic anisotropies may find applications in spintronic devices.
 [219] arXiv:2404.08122 (replaced) [pdf, html, other]

Title: Cavity engineered phononmediated superconductivity in MgB$_2$ from first principles quantum electrodynamicsITe Lu, Dongbin Shin, Mark Kamper Svendsen, Hannes Hübener, Umberto De Giovannini, Simone Latini, Michael Ruggenthaler, Angel RubioComments: 30 pages, 3 figuresSubjects: Superconductivity (condmat.suprcon); Materials Science (condmat.mtrlsci); Applied Physics (physics.appph); Computational Physics (physics.compph)
Strong laser pulses can control superconductivity, inducing nonequilibrium transient pairing by leveraging stronglight matter interaction. Here we demonstrate theoretically that equilibrium groundstate phononmediated superconductive pairing can be affected through the vacuum fluctuating electromagnetic field in a cavity. Using the recently developed ab initio quantum electrodynamical densityfunctional theory approximation, we specifically investigate the phononmediated superconductive behavior of MgB$_2$ under different cavity setups and find that in the strong lightmatter coupling regime its superconducting transition temperature can be, in principles, enhanced by $\approx 73\%$ ($\approx 40\%$) in an inplane (outofplane) polarized cavity. However, in a realistic cavity, we expect the T$_{\rm{c}}$ of MgB$_2$ can increase, at most, by $5$ K via photon vacuum fluctuations. The results highlight that strong lightmatter coupling in extended systems can profoundly alter material properties in a nonperturbative way by modifying their electronic structure and phononic dispersion at the same time. Our findings indicate a pathway to the experimental realization of lightcontrolled superconductivity in solidstate materials at equilibrium via cavitymaterial engineering.
 [220] arXiv:2404.13455 (replaced) [pdf, html, other]

Title: Adiabatic Approximation and AharonovCasher Bands in Twisted Homobilayer TMDsSubjects: Mesoscale and Nanoscale Physics (condmat.meshall); Other Condensed Matter (condmat.other)
Topological flat moiré bands with nearly ideal quantum geometry have been identified in homobilayer transition metal dichalcogenide moiré superlattices, and are thought to be crucial for understanding the fractional Chern insulating states recently observed therein. Previous work proposed viewing the system using an adiabatic approximation that replaces the positiondependence of the layer spinor with a nonuniform periodic effective magnetic field. When the local zeropoint kinetic energy of this magnetic field cancels identically against that of an effective Zeeman energy, a Blochband version of AharonovCasher zeroenergy modes, which we refer to as AharonovCasher band, emerges leading to ideal quantum geometry. Here, we critically examine the validity of the adiabatic approximation and identify the parameter regimes under which AharonovCasher bands emerge. We show that the adiabatic approximation is accurate for a wide range of parameters including those realized in experiments. Furthermore, we show that while the cancellation leading to the emergence of AharonovCasher bands is generally not possible beyond the leading Fourier harmonic, the leading harmonic is the dominant term in the Fourier expansions of the zeropoint kinetic energy and Zeeman energy. As a result, the leading harmonic expansion accurately captures the trend of the bandwidth and quantum geometry, though it may fail to quantitatively reproduce more detailed information about the bands such as the Berry curvature distribution.
 [221] arXiv:2404.14515 (replaced) [pdf, html, other]

Title: Shot noise in coupled electronboson systemsComments: 13 pages, 4 figuresSubjects: Strongly Correlated Electrons (condmat.strel)
The nature of charge carriers in strange metals has become a topic of intense current investigation. Recent shot noise measurements in the quantum critical heavy fermion metal YbRh$_2$Si$_2$ revealed a suppression of the Fano factor that cannot be understood from electronphonon scattering or strong electron correlations in a Fermi liquid, indicating loss of quasiparticles. The experiment motivates the consideration of shot noise in a variety of theoretical models in which quasiparticles may be lost. Here we study shot noise in systems with coexisting itinerant electrons and dispersive bosons, going beyond the regime where the bosons are on their own in thermal equilibrium. We construct the BoltzmannLangevin equations for the coupled system, and show that adequate electronboson couplings restore the Fano factor to its Fermi liquid value. Our findings point to the beyondLandau form of quantum criticality as underlying the suppressed shot noise of strange metals in heavy fermion metals and beyond.
 [222] arXiv:2405.02248 (replaced) [pdf, html, other]

Title: Fractonic criticality in Rydberg atom arraysComments: 11 pages, 5 figuresSubjects: Strongly Correlated Electrons (condmat.strel); Quantum Gases (condmat.quantgas)
Fractonic matter can undergo unconventional phase transitions driven by the condensation of particles that move along subdimensional manifolds. We propose that this type of quantum critical point can be realized in a bilayer of crossed Rydberg chains. This system exhibits a transition between a disordered phase and a chargedensitywave phase with subextensive ground state degeneracy. We show that this transition is described by a stack of critical Ising conformal field theories that become decoupled in the lowenergy limit due to emergent subsystem symmetries. We also analyze the transition using a Majorana meanfield approach for an effective lattice model, which confirms the picture of a fixed point of decoupled critical chains. We discuss the unusual scaling properties and derive anisotropic correlators that provide signatures of subdimensional criticality in this realistic setup.
 [223] arXiv:2405.06212 (replaced) [pdf, other]

Title: Realized Stable BPN at Ambient Pressure by Phosphorus DopingComments: 27 pages, 6 figuresSubjects: Materials Science (condmat.mtrlsci); Chemical Physics (physics.chemph)
Black phosphorus nitrogen (BPN) is an attractive highenergydensity material. However, highpressure synthesized BPN will decompose at lowpressure and cannot be quenched to ambient conditions. Finding a method to stabilize it at 0 GPa is of great significance for its practical applications. However, unlike cgN, LPN, and HLPN, it is always a metastable phase at highpressure up to 260 GPa, and decomposes into chains at 23 GPa. Here, based on the firstprinciples simulations, we find that P atom doping can effectively reduce the synthesis pressure of BPN and maintain its stability at 0 GPa. Uniform distribution of P atom dopants within the layer helps maintain the structural stability of BPN layer at 0 GPa, while interlayer electrostatic interaction induced by NP dipoles enhances its dynamic stability by eliminating interlayer slipping. Furthermore, pressure is conducive to enhancing the stability of BPN and its doped forms by suppressing Nchain dissociation. For the configuration with 12.5% doping concentration, a gravimetric energy density of 8.07 kJ/g can be realized, which is nearly two times higher than TNT.
 [224] arXiv:2405.09450 (replaced) [pdf, other]

Title: Space of nonFermi liquidsComments: 71 pagesSubjects: Strongly Correlated Electrons (condmat.strel); Superconductivity (condmat.suprcon)
In metals, lowenergy effective theories are characterized by a set of coupling functions. Among them, the angledependent Fermi momentum specifies the size and shape of Fermi surface. Since the Fermi momentum grows incessantly under the renormalization group flow, a metallic fixed point is defined only modulo a rescaling of Fermi momentum. In this paper, we discuss the physical consequences of this projective nature of fixed points for nonFermi liquids with hot Fermi surfaces. The first is the absence of a unique dynamical critical exponent that dictates the relative scaling between energy and momentum. The second is mismatches between the scaling dimensions of couplings and their relevancy. Nonetheless, each projective fixed point is characterized by a few marginal and relevant coupling functions, and the notion of universality survives. We illustrate our findings by charting the space of projective fixed points and extracting their universal properties for the Isingnematic quantum critical metal beyond the patch theory. To control the theory, we use the dimensional regularization scheme that tunes the codimension of Fermi surface. Near the upper critical dimension, two exactly marginal coupling functions span the space of stable projective fixed points: functions that specify the shape of the Fermi surface and the angledependent Fermi velocity. All other coupling functions, including the Landau functions and the universal pairing interaction, are fixed by those two marginal functions. With decreasing dimensions, the forward scattering remains irrelevant while the pairing interaction becomes relevant near two dimensions. In two dimensions, it is expected that the universal superconducting fluctuations lower the symmetry of the nonFermi liquid realized above the superconducting transition temperatures from the loop U(1) group to a proper subgroup.
 [225] arXiv:2405.10351 (replaced) [pdf, html, other]

Title: Topological phases of extended SuSchriefferHeegerHubbard modelComments: 16 pages, 11 figuresSubjects: Strongly Correlated Electrons (condmat.strel); Quantum Physics (quantph)
Despite extensive studies on the onedimensional SuSchriefferHeegerHubbard (SSHH) model, the variant incorporating nextnearest neighbour hopping remains largely unexplored. Here, we investigate the groundstate properties of this extended SSHH model using the constrainedpath auxiliaryfield quantum Monte Carlo (CPAFQMC) method. We show that this model exhibits rich topological phases, characterized by robust edge states against interaction. We quantify the properties of these edge states by analyzing spin correlation and secondorder Rényi entanglement entropy. The system exhibits longrange spin correlation and nearzero Rényi entropy at halffilling. Besides, there is a longrange antiferromagnetic order at quarterfilling. Interestingly, an external magnetic field disrupts this longrange antiferromagnetic order, restoring longrange spin correlation and nearzero Rényi entropy. Furthermore, our work provides a paradigm studying topological properties in large interacting systems via the CPAFQMC algorithm.
 [226] arXiv:2405.19517 (replaced) [pdf, html, other]

Title: Highpressure characterization of Ag$_3$AuTe$_2$: Implications for straininduced band tuningJuyeon Won, Rong Zhang, Cheng Peng, Ravhi Kumar, Mebatsion S. Gebre, Dmitry Popov, Russell J. Hemley, Barry Bradlyn, Thomas P. Devereaux, Daniel P. ShoemakerSubjects: Materials Science (condmat.mtrlsci)
Recent band structure calculations have suggested the potential for band tuning in a chiral semiconductor, Ag$_3$AuTe$_2$, to zero upon application of negative strain. In this study, we report on the synthesis of polycrystalline Ag$_3$AuTe$_2$ and investigate its transport, optical properties, and pressure compatibility. Transport measurements reveal the semiconducting behavior of Ag$_3$AuTe$_2$ with high resistivity and an activation energy $E_a$ of 0.2 eV. The optical band gap determined by diffuse reflectance measurements is about three times wider than the experimental $E_a$. Despite the difference, both experimental gaps fall within the range of predicted band gaps by our firstprinciples DFT calculations employing the PBE and mBJ methods. Furthermore, our DFT simulations predict a progressive narrowing of the band gap under compressive strain, with a full closure expected at a strain of 4% relative to the lattice parameter. To evaluate the feasibility of gap tunability at such substantial strain, the highpressure behavior of Ag$_3$AuTe$_2$ was investigated by $in$ $situ$ highpressure Xray diffraction up to 47 GPa. Mechanical compression beyond 4% resulted in a pressureinduced structural transformation, indicating the possibilities of substantial gap modulation under extreme compression conditions.
 [227] arXiv:2405.20752 (replaced) [pdf, html, other]

Title: Experimental evidence of crystalfield, Zeeman splitting, and spinphonon excitations in the quantum supersolid Na2BaCo(PO4)2Ghulam Hussain, Jianbo Zhang, Man Zhang, Lalit Yadav, Yang Ding, Sara Haravifard, Changcheng Zheng, Xiawa WangSubjects: Materials Science (condmat.mtrlsci)
Drawing inspiration from the recent breakthroughs in the \ce{Na_{2}BaCo(PO_{4})_{2}} quantum magnet, renowned for its spin supersolidity phase and its potential for revolutionary cooling applications, our study delves into the intricate interplay among lattice, spin, and orbital degrees of freedom within this intriguing compound. Using meticulous temperature, field, and pressuredependent Raman scattering techniques, we present compelling experimental evidence revealing pronounced crystalelectric field (CEF) excitations, alongside the interplay of CEFphonon interactions. Notably, our experiments elucidate all electronic transitions from $j_{1 / 2}$ to $j_{3 / 2}$ and from $j_{1 / 2}$ to $j_{5 / 2}$, with energy level patterns closely aligned with theoretical predictions based on pointcharge models. Furthermore, the application of a magnetic field and pressure reveals Zeeman splittings characterized by Landég factors as well as the CEFphonon resonances. The anomalous shift in coupled peak at low temperatures originates from the hybridization of CEF and phonon excitations due to their close energy proximity. These findings constitute a significant step towards unraveling the fundamental properties of this exotic quantum material for future research in fundamental physics or engineering application.
 [228] arXiv:2406.04120 (replaced) [pdf, html, other]

Title: Transverse Field $\gamma$Matrix Spin ChainsComments: 12 pages, 9 figures; added references for section 2, corrected a typo in appendix DSubjects: Strongly Correlated Electrons (condmat.strel)
We introduce a simple lattice spin model that is written in terms of the wellknown fourdimensional $\gamma$matrix representation of the Clifford algebra. The local spins with a fourdimensional Hilbert space transform in a spinorial $(1/2,0) \oplus (0,1/2)$ representation of $SO(4)$, a symmetry of our model. When studied on a chain, and as a function of a transverse field tuning parameter, our model undergoes a quantum phase transition from a valence bond solid phase to a critical phase that is described by an $SU(2)_1$ WZW field theory.
 [229] arXiv:2406.05454 (replaced) [pdf, html, other]

Title: Generating Lattice Noninvertible SymmetriesComments: 46 pages, 5 figures, 2 tables; v2 reference addedSubjects: Strongly Correlated Electrons (condmat.strel); High Energy Physics  Theory (hepth)
Lattice noninvertible symmetries have rich fusion structures and play important roles in understanding various exotic topological phases. In this paper, we explore methods to generate new lattice noninvertible transformations/symmetries from a given noninvertible seed transformation/symmetry. The new lattice noninvertible symmetry is constructed by composing the seed transformations on different sites or sandwiching a unitary transformation between the transformations on the same sites. In addition to known noninvertible symmetries with fusion algebras of TambaraYamagami $\mathbb Z_N\times\mathbb Z_N$ type, we obtain a new noninvertible symmetry in models with $\mathbb Z_N$ dipole symmetries. We name the latter the dipole KramersWannier symmetry because it arises from gauging the dipole symmetry. We further study the dipole KramersWannier symmetry in depth, including its topological defect, its anomaly and its associated generalized KennedyTasaki transformation.
 [230] arXiv:2406.05701 (replaced) [pdf, html, other]

Title: Intrinsic secondorder topological insulators in twodimensional polymorphic graphyne with sublattice approximationSubjects: Materials Science (condmat.mtrlsci)
In two dimensions, intrinsic secondorder topological insulators (SOTIs) are characterized by topological corner states that emerge at the intersections of distinct edges with reversed mass signs, enforced by spatial symmetries. Here, we present a comprehensive investigation within the class BDI to clarify the symmetry conditions ensuring the presence of intrinsic SOTIs in two dimensions. We reveal that the (anti)commutation relationship between spatial symmetries and chiral symmetry is a reliable indicator of intrinsic corner states. Through firstprinciples calculations, we identify several ideal candidates within carbonbased polymorphic graphyne structures for realizing intrinsic SOTIs under sublattice approximation. Furthermore, we show that the corner states in these materials persist even in the absence of sublattice approximation. Our findings not only deepen the understanding of higherorder topological phases but also open new pathways for realizing topological corner states that are readily observable.
 [231] arXiv:2406.05842 (replaced) [pdf, html, other]

Title: Replica symmetry breaking in spin glasses in the replicafree Keldysh formalismComments: 17 pages, 4 figures, submitted versionSubjects: Disordered Systems and Neural Networks (condmat.disnn); Statistical Mechanics (condmat.statmech); Strongly Correlated Electrons (condmat.strel); Mathematical Physics (mathph); Quantum Physics (quantph)
At asymptotically late times ultrametricity can emerge from the persistent slow aging dynamics of the glass phase. We show that this suffices to recover the breaking of replica symmetry in meanfield spin glasses from the late time limit of the time evolution using the Keldysh path integral. This provides an alternative approach to replica symmetry breaking by connecting it rigorously to the dynamic formulation. Stationary spin glasses are thereby understood to spontaneously break thermal symmetry, or the KuboMartinSchwinger relation of a state in global thermal equilibrium. We demonstrate our general statements for the spherical quantum $p$spin model and the quantum SherringtonKirkpatrick model in the presence of transverse and longitudinal fields. In doing so, we also derive their dynamical GinzburgLandau effective Keldysh actions starting from microscopic quantum models.
 [232] arXiv:2406.07608 (replaced) [pdf, html, other]

Title: Strange metal and superconductor in the twodimensional YukawaSachdevYeKitaev modelChenyuan Li, Davide Valentinis, Aavishkar A. Patel, Haoyu Guo, Jörg Schmalian, Subir Sachdev, Ilya EsterlisComments: 7+18 pages, 5+12 figures; references addedSubjects: Strongly Correlated Electrons (condmat.strel); Superconductivity (condmat.suprcon); High Energy Physics  Theory (hepth)
The twodimensional YukawaSachdevYeKitaev (YSYK) model provides a universal theory of quantum phase transitions in metals in the presence of quenched random spatial fluctuations in the local position of the quantum critical point. It has a Fermi surface coupled to a scalar field by spatially random Yukawa interactions. We present full numerical solutions of a selfconsistent disorder averaged analysis of the YSYK model in both the normal and superconducting states, obtaining electronic spectral functions, frequencydependent conductivity, and superfluid stiffness. Our results reproduce key aspects of observations in the cuprates as analyzed by Michon $et$ $al$. (Nat. Comm. $\bf{14}$, 3033 (2023)). We also find a regime of increasing zero temperature superfluid stiffness with decreasing superconducting critical temperature, as is observed in bulk cuprates.
 [233] arXiv:2406.09674 (replaced) [pdf, html, other]

Title: Chiral excitonic systems in twisted bilayers from F\"{o}rster coupling and unconventional excitonic Hall effectsComments: 8 pages,4 figuresSubjects: Mesoscale and Nanoscale Physics (condmat.meshall)
In twisted bilayer semiconductors with arbitrary twisting angles, a chiral excitonic system can arise from the interlayer electronhole Coulomb exchange interaction (Förster coupling) that hybridizes the anisotropic intralayer excitons from individual layers. We present a general framework for the effective exciton Hamiltonian taking into account the electronhole Coulomb exchange, using twisted homobilayer systems composed of transition metal dichalcogenides or black phosphorus as examples. We demonstrate that such chiral excitonic systems can feature unconventional Hall (Nernst) effects arising from quantum geometric properties characteristic of the layer hybridized wavefunctions under the chiral symmetry, for example, the timereversal even layer Hall counter flow and the crossed nonlinear dynamical Hall effect, when mechanical and statistical force (temperature or density gradient) drives the exciton flow.
 [234] arXiv:2406.11372 (replaced) [pdf, html, other]

Title: Universal spectrum of non efimovian threebody resonances at finite scattering lengthComments: In this new version, a typo on the number page 4, last line, first column is correctedSubjects: Quantum Gases (condmat.quantgas); Nuclear Theory (nuclth)
Using exact solutions of the threebody problem, the spectrum of non efimovian threebody resonances for two identical particles interacting with another one is derived in the regime of large but finite scattering length. The universality of the problem is depicted by using a contact model in the generalized effective range approximation, parameterized by two threebody parameters and the scattering length.
 [235] arXiv:2406.12291 (replaced) [pdf, html, other]

Title: Electronic correlations arising from antiStoner spin excitations: an ab initio study of itinerant ferro and antiferromagnetSubjects: Materials Science (condmat.mtrlsci)
The antiStoner excitations are a spinflips in which, effectively, an electron is promoted from a minority to a majority spin state, i.e., complementary to Stoner excitations and spinwaves. Since their spectral power is negligible in strong itinerant ferromagnets and they are identically absent in the ferromagnetic Heisenberg model, their properties and role in correlating electrons were hardly investigated so far. On the other hand, they are present in weak ferromagnets, fcc Ni being a prominent example, and both types of spinflips (downtoup and uptodown) must be treated on the equal footing in systems with the degenerate spin up and down bands, in particular antiferromagnets in which case we choose CrSb as a model system. For these two materials we evaluate the strength of the effective interaction between the quasiparticles and the gas of virtual spinflip excitations. To this end, we compute the corresponding selfenergy taking advantage of our novel efficient \textit{ab initio} numerical scheme. We find that in Ni the bandstructure renormalization due to the antiStoner processes is weaker than the one due to Stonertype magnons in the majority spin channel but the two become comparable in the minority one. The effect can be traced back primarily to the spectral strength of the respective spin excitations and the densities of the final available quasiparticle states in the scattering process. For the antiferromagnet, the situation is more complex and we observe that the electronmagnon interaction is sensitive not only to these densities of states but critically to the spatial shapes of the coupling magnonic modes as well.
 [236] arXiv:2406.12357 (replaced) [pdf, html, other]

Title: Clusterprojected matrix product state: framework for engineering exact quantum manybody ground states in one and two dimensionsSubjects: Strongly Correlated Electrons (condmat.strel)
We propose a framework to design concurrently a frustrationfree quantum manybody Hamiltonian and its exact ground states in one and two dimensions using an elementary matrix product state (MPS) representation. Our approach strategically chooses a local cluster Hamiltonian, which is arranged to overlap with neighboring clusters on a designed lattice. Ensuring that there exists a state spanned on the lattice that has its local submanifolds as the lowestenergy eigenstate of every cluster, we can construct the bulk Hamiltonian as the sum of the cluster Hamiltonians. The key to find such a solution is a systematic protocol, which projects out excited states on every cluster using MPS and effectively entangles the cluster states. The protocol offers several advantages, including the ability to achieve exact manybody groundstate solutions at nearly equal cost in one and two dimensions including those with gapless or longrange entangled ground states, flexibility in designing Hamiltonians unbiasedly across various forms of models, and numerically feasible validation through energy calculations. Our protocol offers exact ground state for any givenfrustration free Hamiltonian, and enables the exploration of exact phase boundaries and the analysis of even a spatially nonuniform random system, providing platforms for quantum simulations and benchmarks.
 [237] arXiv:2406.12728 (replaced) [pdf, html, other]

Title: Toward meanfield bound for critical temperature on Nishimori lineComments: 9pages, 0 figureSubjects: Disordered Systems and Neural Networks (condmat.disnn); Statistical Mechanics (condmat.statmech)
The critical inverse temperature of the meanfield approximation gives a lower bound of the true critical inverse temperature in a broad class of ferromagnetic spin models, which is called the meanfield bound for the critical temperature. In this study, we explore the possibility of a corresponding meanfield bound for the critical temperature in Ising spinglass models with Gaussian randomness on the Nishimori line. On the Nishimori line, the critical inverse temperature of the meanfield approximation is given by $\beta_{MF}^{NL}=\sqrt{1/z}$, where $z$ denotes the coordination number. Using the Griffiths inequalities on the Nishimori line, we prove that there is zero spontaneous magnetization in the hightemperature region $\beta < \beta_{MF}^{NL}/2$. In other words, the true critical inverse temperature $\beta_c^{NL}$ of the Nishimori line is always bounded by $\beta_c^{NL} \ge \beta_{MF}^{NL}/2$. Unfortunately, we did not succeed in obtaining the corresponding meanfield bound $\beta_c^{NL} \ge \beta_{MF}^{NL}$ on the Nishimori line.
 [238] arXiv:2009.09208 (replaced) [pdf, other]

Title: The quantum Ising chain for beginnersJournalref: SciPost Phys. Lect. Notes 82 (2024)Subjects: Quantum Physics (quantph); Quantum Gases (condmat.quantgas)
We present here various techniques to work with clean and disordered quantum Ising chains, for the benefit of students and nonexperts. Starting from the JordanWigner transformation, which maps spin1/2 systems into fermionic ones, we review some of the basic approaches to deal with the superconducting correlations that naturally emerge in this context. In particular, we analyse the form of the ground state and excitations of the model, relating them to the symmetrybreaking physics, and illustrate aspects connected to calculating dynamical quantities, thermal averages, correlation functions and entanglement entropy. A few problems provide simple applications of the techniques.
 [239] arXiv:2302.04278 (replaced) [pdf, html, other]

Title: Error Mitigation Thresholds in Noisy Random Quantum CircuitsComments: 11 pages, 4 figuresSubjects: Quantum Physics (quantph); Statistical Mechanics (condmat.statmech)
Extracting useful information from noisy nearterm quantum simulations requires error mitigation strategies. A broad class of these strategies rely on precise characterization of the noise source. \new{We study the robustness of probabilistic error cancellation and tensor network error mitigation when the noise is imperfectly characterized}. We adapt an ImryMa argument to predict the existence of a threshold in the robustness of these error mitigation methods for random spatially local circuits in spatial dimensions $D \geq 2$: noise characterization disorder below the threshold rate allows for error mitigation up to times that scale with the number of qubits. For onedimensional circuits, by contrast, mitigation fails at an $\mathcal{O}(1)$ time for any imperfection in the characterization of disorder. As a result, error mitigation is only a practical method for sufficiently wellcharacterized noise. We discuss further implications for tests of quantum computational advantage, faulttolerant probes of measurementinduced phase transitions, and quantum algorithms in nearterm devices.
 [240] arXiv:2305.13992 (replaced) [pdf, html, other]

Title: Liouville Space Neural Network Representation of Density MatricesComments: 13 pages, 9 figures. Updated to published versionJournalref: Phys. Rev. A 109, 062215 (2024)Subjects: Quantum Physics (quantph); Mesoscale and Nanoscale Physics (condmat.meshall)
Neural network quantum states as ansatz wavefunctions have shown a lot of promise for finding the ground state of spin models. Recently, work has been focused on extending this idea to mixed states for simulating the dynamics of open systems. Most approaches so far have used a purification ansatz where a copy of the system Hilbert space is added which when traced out gives the correct density matrix. Here, we instead present an extension of the Restricted Boltzmann Machine which directly represents the density matrix in Liouville space. This allows the compact representation of states which appear in meanfield theory. We benchmark our approach on two different version of the dissipative transverse field Ising model which show our ansatz is able to compete with other stateoftheart approaches.
 [241] arXiv:2306.03327 (replaced) [pdf, html, other]

Title: Superfluid extension of the selfconsistent timedependent band theory for neutron star matter: Antientrainment versus superfluid effects in the slab phaseComments: 21 pages, 11 figures, 4 tables. v4  Version accepted for publication in Physical Review C, selected as an Editors' SuggestionJournalref: Phys. Rev. C 109, 065804 (2024)Subjects: Nuclear Theory (nuclth); High Energy Astrophysical Phenomena (astroph.HE); Quantum Gases (condmat.quantgas)
Background: The inner crust of neutron stars consists of a Coulomb lattice of neutronrich nuclei, immersed in a sea of superfluid neutrons with background relativistic electron gas. A proper quantum mechanical treatment for such a system under a periodic potential is the band theory of solids. The effect of band structure on the effective mass of dripped neutrons, the socalled \textit{entrainment effect}, is currently in a debatable situation, and it has been highly desired to develop a nuclear band theory taking into account neutron superfluidity in a fully selfconsistent manner.
Purpose: The main purpose of the present work is twofold: 1) to develop a formalism of the timedependent selfconsistent band theory, taking full account of nuclear superfluidity, based on timedependent density functional theory (TDDFT) extended for superfluid systems, and 2) to quantify the effects of band structure and superfluidity on crustal properties, applying the formalism to the slab phase of nuclear matter in the $\beta$ equilibrium.
Results: Static calculations have been performed for a range of baryon (nucleon) number density ($n_b=0.040.07$ fm$^{3}$) under the $\beta$equilibrium condition with and without superfluidity, for various interslab spacings. From a dynamic response to an external potential, we extract the collective mass of a slab and that of protons immersed in neutron superfluid. From the results, we find that the collective mass of a slab is substantially reduced by 57.582.5\% for $n_b=0.040.07$ fm$^{3}$, which corresponds to an enhancement of conduction neutron number density and, thus, to a reduction of the neutron effective mass, which we call the antientrainment effect. We discuss novel phenomena associated with superfluidity, quasiparticle resonances in the inner crust, which are absent in normal systems.
*shortened due to the arXiv word limit.  [242] arXiv:2307.05125 (replaced) [pdf, html, other]

Title: Linearizing Binary Optimization Problems Using Variable Posets for Ising MachinesComments: 22 pages. This article has been accepted for publication in IEEE Transactions on Emerging Topics in ComputingSubjects: Optimization and Control (math.OC); Statistical Mechanics (condmat.statmech); Emerging Technologies (cs.ET); Applied Physics (physics.appph)
Ising machines are nextgeneration computers expected to efficiently sample nearoptimal solutions of combinatorial optimization problems. Combinatorial optimization problems are modeled as quadratic unconstrained binary optimization (QUBO) problems to apply an Ising machine. However, current stateoftheart Ising machines still often fail to output nearoptimal solutions due to the complicated energy landscape of QUBO problems. Furthermore, the physical implementation of Ising machines severely restricts the size of QUBO problems to be input as a result of limited hardware graph structures. In this study, we take a new approach to these challenges by injecting auxiliary penalties preserving the optimum, which reduces quadratic terms in QUBO objective functions. The process simultaneously simplifies the energy landscape of QUBO problems, allowing the search for nearoptimal solutions, and makes QUBO problems sparser, facilitating encoding into Ising machines with restriction on the hardware graph structure. We propose linearization of QUBO problems using variable posets as an outcome of the approach. By applying the proposed method to synthetic QUBO instances and to multidimensional knapsack problems, we empirically validate the effects on enhancing minorembedding of QUBO problems and the performance of Ising machines.
 [243] arXiv:2307.10327 (replaced) [pdf, html, other]

Title: Adaptive Trotterization for timedependent Hamiltonian quantum dynamics using piecewise conservation lawsComments: 7+5pages, 5+2 figures. Accepted in PRLSubjects: Quantum Physics (quantph); Quantum Gases (condmat.quantgas); Statistical Mechanics (condmat.statmech)
Digital quantum simulation relies on Trotterization to discretize time evolution into elementary quantum gates. On current quantum processors with notable gate imperfections, there is a critical tradeoff between improved accuracy for finer timesteps, and increased error rate on account of the larger circuit depth. We present an adaptive Trotterization algorithm to cope with timedependent Hamiltonians, where we propose a concept of piecewise "conserved" quantities to estimate errors in the time evolution between two (nearby) points in time; these allow us to bound the errors accumulated over the full simulation period. They reduce to standard conservation laws in the case of timeindependent Hamiltonians, for which we first developed an adaptive Trotterization scheme [PRX Quantum 4, 030319]. We validate the algorithm for a timedependent quantum spin chain, demonstrating that it can outperform the conventional Trotter algorithm with a fixed step size at a controlled error.
 [244] arXiv:2307.14892 (replaced) [pdf, html, other]

Title: A minimal quantum heat pump based on highfrequency driving and nonMarkovianityComments: 9 pages, 5 FiguresJournalref: Phys. Rev. E 109, 064121 (2024)Subjects: Quantum Physics (quantph); Quantum Gases (condmat.quantgas); Statistical Mechanics (condmat.statmech)
We propose a minimal setup for a quantum heat pump, consisting of two tunnelcoupled quantum dots, each hosting a single level and each being coupled to a different fermionic reservoir. The working principle relies on both nonMarkovian systembath coupling and driving induced resonant coupling. We describe the system using a reactioncoordinate mapping in combination with FloquetBornMarkov theory and characterize its performance.
 [245] arXiv:2309.08666 (replaced) [pdf, html, other]

Title: Variational Embeddings for Many Body Quantum SystemsComments: 15 pages, 7 figures. The framework has been extended to include embeddings of classical variational methodsSubjects: Quantum Physics (quantph); Other Condensed Matter (condmat.other); Computational Physics (physics.compph)
We propose a variational scheme to represent composite quantum systems using multiple parameterized functions of varying accuracies on both classical and quantum hardware. The approach follows the variational principle over the entire system, and is naturally suited for scenarios where an accurate description is only needed in a smaller subspace. We show how to include quantum devices as highaccuracy solvers on these correlated degrees of freedom, while handling the remaining contributions with a classical device. We demonstrate the effectiveness of the protocol on spin chains and small molecules and provide insights into its accuracy and computational cost.
 [246] arXiv:2309.09625 (replaced) [pdf, html, other]

Title: Exceptional nexus in BoseEinstein condensates with collective dissipationChenhao Wang, Nan Li, Jin Xie, Cong Ding, Zhonghua Ji, Liantuan Xiao, Suotang Jia, Ying Hu, Yanting ZhaoComments: accepted by PRLSubjects: Quantum Physics (quantph); Quantum Gases (condmat.quantgas)
In multistate nonHermitian systems, higherorder exceptional points and exotic phenomena with no analogues in twolevel systems arise. A paradigm is the exceptional nexus (EX), a thirdorder EP as the cusp singularity of exceptional arcs (EAs), that has a hybrid topological nature. Using atomic BoseEinstein condensates to implement a dissipative threestate system, we experimentally realize an EX within a twoparameter space, despite the absence of symmetry. The engineered dissipation exhibits density dependence due to the collective atomic response to resonant light. Based on extensive analysis of the system's decay dynamics, we demonstrate the formation of an EX from the coalescence of two EAs with distinct geometries. These structures arise from the different roles played by dissipation in the strong coupling limit and quantum Zeno regime. Our work paves the way for exploring higherorder exceptional physics in the manybody setting of ultracold atoms.
 [247] arXiv:2310.09189 (replaced) [pdf, html, other]

Title: Adiabatic perturbation theory for twocomponent systems with one heavy componentSubjects: Quantum Physics (quantph); Other Condensed Matter (condmat.other)
Perturbation theory with respect to the kinetic energy of the heavy component of a twocomponent quantum system is introduced. An effective Hamiltonian that is accurate to second order in the inverse heavy mass is derived. It contains a new form of kinetic energy operator with a Hermitian mass tensor and a complexvalued vector potential. All of the potentials in the effective Hamiltonian can be expressed in terms of covariant derivatives and a resolvent operator. The most salient application of the theory is to systems of electrons and nuclei. The accuracy of the theory is verified numerically in a model diatomic molecule and analytically in a vibronic coupling model.
 [248] arXiv:2310.12624 (replaced) [pdf, html, other]

Title: Poles, Shocks and Tygers: The Timereversible Burgers equationComments: 25 pages, 18 figuresSubjects: Fluid Dynamics (physics.fludyn); Statistical Mechanics (condmat.statmech); Chaotic Dynamics (nlin.CD)
We construct a formally timereversible, onedimensional forced Burgers equation by imposing a global constraint of energy conservation, wherein the constant viscosity is modified to a fluctuating statedependent dissipation coefficient. The system exhibits dynamical properties which bear strong similarities with those observed for the Burgers equation and can be understood using the dynamics of the poles, shocks, and truncation effects, such as tygers. A complex interplay of these give rise to interesting statistical regimes ranging from hydrodynamic behavior to a completely thermalized warm phase. The end of the hydrodynamic regime is associated with the appearance of a shock in the solution and a continuous transition leading to a truncationdependent state. Beyond this, the truncation effects such as tygers and the appearance of secondary discontinuity at the resonance point in the solution strongly influence the statistical properties. These disappear at the second transition, at which the global quantities exhibit a jump and attain values that are consistent with the establishment of a quasiequilibrium state characterized by energy equipartition among the Fourier modes. Our comparative analysis shows that the macroscopic statistical properties of the formally timereversible system and the Burgers equation are equivalent in all the regimes, irrespective of the truncation effects, and this equivalence is not just limited to the hydrodynamic regime, thereby further strengthening the Gallavotti's equivalence conjecture. The properties of the system are further examined by inspecting the complex space singularities in the velocity field of the Burgers equation. Furthermore, an effective theory is proposed to describe the discontinuous transition.
 [249] arXiv:2310.20309 (replaced) [pdf, html, other]

Title: Tensor formalism for predicting synaptic connections with ensemble modeling or optimizationComments: 31 pages, 6 figures, 2 tablesSubjects: Neurons and Cognition (qbio.NC); Disordered Systems and Neural Networks (condmat.disnn); Biological Physics (physics.bioph)
Theoretical neuroscientists often try to understand how the structure of a neural network relates to its function by focusing on structural features that would either follow from optimization or occur consistently across possible implementations. Both optimization theories and ensemble modeling approaches have repeatedly proven their worth, and it would simplify theory building considerably if predictions from both theory types could be derived and tested simultaneously. Here we show how tensor formalism from theoretical physics can be used to unify and solve many optimization and ensemble modeling approaches to predicting synaptic connectivity from neuronal responses. We specifically focus on analyzing the solution space of synaptic weights that allow a thresholdlinear neural network to respond in a prescribed way to a limited number of input conditions. For optimization purposes, we compute the synaptic weight vector that minimizes an arbitrary quadratic loss function. For ensemble modeling, we identify synaptic weight features that occur consistently across all solutions bounded by an arbitrary ellipsoid. We derive a common solution to this suite of nonlinear problems by showing how each of them reduces to an equivalent linear problem that can be solved analytically. Although identifying the equivalent linear problem is nontrivial, our tensor formalism provides an elegant geometrical perspective that allows us to solve the problem approximately in an analytical way or exactly using numeric methods. The final algorithm is applicable to a wide range of interesting neuroscience problems, and the associated geometric insights may carry over to other scientific problems that require constrained optimization.
 [250] arXiv:2312.03489 (replaced) [pdf, html, other]

Title: Decomposing Thermodynamic Dissipation of Linear Langevin Systems via Oscillatory Modes and Its Application to Neural DynamicsSubjects: Neurons and Cognition (qbio.NC); Statistical Mechanics (condmat.statmech)
Recent developments in stochastic thermodynamics have elucidated various relations between the entropy production rate (thermodynamic dissipation) and the physical limits of information processing in nonequilibrium dynamical systems. These findings have opened new perspectives in analyzing real biological systems. In neuroscience, the importance of quantifying entropy production has attracted attention for understanding information processing in the brain. However, the relationship between the entropy production rate and oscillations, which are common in many biological systems, remains unclear. For instance, neural oscillations like delta, theta, and alpha waves play crucial roles in brain information processing. Here, we derive a novel decomposition of the entropy production rate of linear Langevin systems. We show that one component of the entropy production rate, called the housekeeping entropy production rate, can be decomposed into independent positive contributions from oscillatory modes. Our decomposition enables us to calculate the contribution of oscillatory modes to the housekeeping entropy production rate. In addition, when the noise matrix is diagonal, the contribution of each oscillatory mode can be further decomposed into the contribution of each system element. To demonstrate the utility of our decomposition, we applied it to an electrocorticography (ECoG) dataset recorded during awake and anesthetized conditions in monkeys, where the oscillatory properties change drastically. We showed consistent trends across different monkeys: the contribution of delta band was larger in the anesthetized condition than in the awake condition, while those from higher frequency bands, such as the theta band, were smaller. These results allow us to interpret the changes in neural oscillation in terms of stochastic thermodynamics and the physical limits of information processing.
 [251] arXiv:2312.08065 (replaced) [pdf, html, other]

Title: Hubbard physics with Rydberg atoms: using a quantum spin simulator to simulate strong fermionic correlationsJournalref: Phys. Rev. B 109, 2024, 174409Subjects: Quantum Physics (quantph); Strongly Correlated Electrons (condmat.strel)
We propose a hybrid quantumclassical method to investigate the equilibrium physics and the dynamics of strongly correlated fermionic models with spinbased quantum processors. Our proposal avoids the usual pitfalls of fermiontospin mappings thanks to a slavespin method which allows to approximate the original Hamiltonian into a sum of selfcorrelated freefermions and spin Hamiltonians. Taking as an example a Rydbergbased analog quantum processor to solve the interacting spin model, we avoid the challenges of variational algorithms or Trotterization methods. We explore the robustness of the method to experimental imperfections by applying it to the halffilled, singleorbital Hubbard model on the square lattice in and out of equilibrium. We show, through realistic numerical simulations of current Rydberg processors, that the method yields quantitatively viable results even in the presence of imperfections: it allows to gain insights into equilibrium Mott physics as well as the dynamics under interaction quenches. This method thus paves the way to the investigation of physical regimes  whether outofequilibrium, doped, or multiorbital  that are difficult to explore with classical processors.
 [252] arXiv:2401.07449 (replaced) [pdf, html, other]

Title: Fock space: A bridge between Fredholm index and the quantum Hall effectComments: Revision with extra example in Section 10. 38 pages, 1 figureSubjects: Mathematical Physics (mathph); Mesoscale and Nanoscale Physics (condmat.meshall); Functional Analysis (math.FA); Quantum Algebra (math.QA)
We compute the quantized Hall conductance at various Landau levels by using the classic trace. The computations reduce to the single elementary one for the lowest Landau level. By using the theories of HeltonHoweCareyPincus, and Toeplitz operators on the classic Fock space and higher Fock spaces, the Hall conductance is naturally identified with a Fredholm index. This brings new mathematical insights to the extraordinary precision of quantization observed in quantum Hall measurements.
 [253] arXiv:2401.13372 (replaced) [pdf, html, other]

Title: Influence of resonant plasmonic nanoparticles on optically accessing the valley degree of freedom in 2D semiconductorsTobias Bucher (1, 2, 3), Zlata Fedorova (1, 2, 3), Mostafa Abasifard (2, 1, 3), Rajeshkumar Mupparapu (2), Matthias J. Wurdack (4, 1, 2, 3), Emad Najafidehaghani (5), Ziyang Gan (5), Heiko Knopf (6, 2, 3), Antony George (5, 3), Falk Eilenberger (6, 2, 3, 7), Thomas Pertsch (2, 3, 6, 7), Andrey Turchanin (5, 3, 8), Isabelle Staude (1, 2, 3, 7) ((1) Institute of Solid State Physics, Friedrich Schiller University Jena, Germany (2) Institute of Applied Physics, Friedrich Schiller University Jena, Germany (3) Abbe Center of Photonics, Friedrich Schiller University Jena, Germany (4) ARC Centre of Excellence in Future LowEnergy Electronics Technologies and Department of Quantum Science and Technology, Research School of Physics, The Australian National University, Canberra, Australia (5) Institute of Physical Chemistry, Friedrich Schiller University Jena, Germany (6) Fraunhofer Institute for Applied Optics and Precision Engineering IOF, Jena, Germany (7) Max Planck School of Photonics, Germany (8) Jena Center for Soft Matter (JCSM), Jena, Germany)Comments: Tobias Bucher and Zlata Fedorova contributed equally to this work. 29 pages, 6 figuresSubjects: Optics (physics.optics); Mesoscale and Nanoscale Physics (condmat.meshall)
The valley degree of freedom is one of the most intriguing properties of atomically thin transition metal dichalcogenides. Together with the possibility to address this degree of freedom by valleycontrasting optical selection rules, it has the potential to enable a completely new class of future electronic and optoelectronic devices. Resonant optical nanostructures emerge as promising tools for interacting with and controlling the valley degree of freedom at the nanoscale. However, a critical understanding gap remains in how nanostructures and their nearfields affect the circular polarization properties of valleyselective emission hindering further developments in this field. In order to address this issue, our study delves into the experimental investigation of a hybrid model system where valleyspecific emission from a monolayer of molybdenum disulfide is interacting with a resonant plasmonic nanosphere. Contrary to the simple intuition suggesting that a centrosymmetric nanoresonator preserves the degree of circular polarization in the forward scattered farfield by angular momentum conservation, our cryogenic photoluminescence microscopy reveals that the light emitted from the nanoparticle position is largely unpolarized, i.e. we observe depolarization. We rigorously study the nature of this phenomenon numerically considering the monolayernanoparticle interaction at different levels including excitation and emission. In doing so, we find that the farfield degree of polarization strongly reduces in the hybrid system when including excitons emitting from outside of the system's symmetry point, which in combination with depolarisation at the excitation level causes the observed effect. Our results highlight the importance of considering spatially distributed emitters for precise predictions of polarization responses in these hybrid systems.
 [254] arXiv:2402.08634 (replaced) [pdf, html, other]

Title: Coexistence of uniform and oscillatory states resulting from nonreciprocity and conservation lawsSubjects: Pattern Formation and Solitons (nlin.PS); Soft Condensed Matter (condmat.soft)
Employing a twospecies CahnHilliard model with nonreciprocal interactions we show that the interplay of nonreciprocity and conservation laws results in the coexistence of uniform stationary and oscillatory phases as well as of uniform and crystalline phases. For nonequilibrium models with a \textit{spurious gradient dynamics structure} [T. FrohoffH{ü}lsmann \textit{et al.}, Phys.\ Rev.\ E 107, 64210 (2023)] the coexistence between nonequilibrium phases can nevertheless be predicted by a Maxwell doubletangent construction including phases with sustained outofequilibrium dynamics. This is further corroborated by bifurcation studies and time simulations.
 [255] arXiv:2403.01716 (replaced) [pdf, html, other]

Title: Dynamics of a Generalized Dicke Model for Spin1 AtomsComments: 16 pages, 12 figuresSubjects: Quantum Physics (quantph); Quantum Gases (condmat.quantgas); Atomic Physics (physics.atomph)
The Dicke model is a staple of theoretical cavity Quantum Electrodynamics (cavity QED), describing the interaction between an ensemble of atoms and a single radiation mode of an optical cavity. It has been studied both quantum mechanically and semiclassically for twolevel atoms, and demonstrates a rich variety of dynamics such as phase transitions, phase multistability, and chaos. In this work we explore an open, spin1 Dicke model with independent co and counterrotating coupling terms as well as a quadratic Zeeman shift enabling control over the atomic energylevel structure. We investigate the stability of operator and moment equations under two approximations and show the system undergoes phase transitions. To compliment these results, we relax the aforementioned approximations and investigate the system semiclassically. We show evidence of phase transitions to steadystate and oscillatory superradiance in this semiclassical model, as well as the emergence of chaotic dynamics. The varied and complex behaviours admitted by the model highlights the need to more rigorously map its dynamics.
 [256] arXiv:2403.08366 (replaced) [pdf, other]

Title: Amplified linear and nonlinear chiral sensing assisted by anapole modes in hybrid metasurfacesComments: This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Appl. Phys. Lett. 124, 251701 (2024) and may be found at https://doi.org/10.1063/5.0212393. Copyright (2024) Authors. This article is distributed under a Creative Commons AttributionNonCommercialNoDerivs 4.0 International (CC BYNCND) LicenseJournalref: Appl. Phys. Lett. 124, 251701 (2024)Subjects: Optics (physics.optics); Materials Science (condmat.mtrlsci); Applied Physics (physics.appph)
The interaction between chiral molecules and circularly polarized light is largely influenced by the local optical chirality density. This interaction prompts substantial demand of the design of nanophotonic platforms capable of enhancing such effects across large and accessible volumes. Such a magnification requires nanostructures that provide strong electric and magnetic field enhancements while preserving the phase relation of circular light. Dielectric nanostructures, particularly those able to support resonances, are ideal candidates for this task due to their capacity for high electric and magnetic field enhancements. On the other hand, efficient third harmonic generation calls for strong electric field resonances within dielectric materials, a feature often boosted by incorporating plasmonic materials into hybrid systems. In this work, we numerically propose a coupled silicon diskgold ring system that can exploit the anapoleinduced field confinement to provide a broadband magnified circular dichroism under realistic conditions, reaching values up to a 230fold enhancement. We also demonstrate that this structure can be employed as an efficient third harmonic generator which, when integrated with chiral media, enables an 800fold enhancement in circular dichroism. Furthermore, we show that pulsed illumination at intensities up to 10 GW/cm2 does not induce temperature increments that could potentially damage the samples. These findings suggest that this system can be a promising and versatile approach towards ultrasensitive chiral sensing.
 [257] arXiv:2403.10277 (replaced) [pdf, html, other]

Title: Delayed interactions in the noisy voter model through the periodic polling mechanismComments: submitted; 22 pages, 11 figures, 54 referencesSubjects: Physics and Society (physics.socph); Statistical Mechanics (condmat.statmech)
We investigate the effects of delayed interactions on the stationary distribution of the noisy voter model. We assume that the delayed interactions occur through the periodic polling mechanism and replace the original instantaneous twoagent interactions. In our analysis, we require that the polling period aligns with the delay in announcing poll outcomes. As expected, when the polling period is relatively short, the model with delayed interactions is almost equivalent to the original model. As the polling period increases, oscillatory behavior emerges, but the model with delayed interactions still converges to stationary distribution. The stationary distribution resembles a Betabinomial distribution, with its shape parameters scaling with the polling period. The observed scaling behavior is nonmonotonic. Namely, the shape parameters peak at some intermediate polling period.
 [258] arXiv:2403.14417 (replaced) [pdf, html, other]

Title: A twodimensional vertex model for curvy cellcell interfaces at the subcellular scaleComments: 18 pages, 16 figuresSubjects: Biological Physics (physics.bioph); Soft Condensed Matter (condmat.soft)
Crosssections of cell shapes in a tissue monolayer typically resemble a tiling of convex polygons. Yet, examples exist where the polygons are not convex with curved cellcell interfaces, as seen in the adaxial epidermis. To date, twodimensional vertex models predicting the structure and mechanics of cell monolayers have been mostly limited to convex polygons. To overcome this limitation, we introduce a framework to study curvy cellcell interfaces at the subcellular scale within vertex models by using a parameterized curve between vertices that is expanded in a Fourier series and whose coefficients represent additional degrees of freedom. This extension to nonconvex polygons allows for cells with same shape index, or dimensionless perimeter, to be, for example, either elongated or globular with lobes. In the presence of applied, anisotropic stresses, we find that local, subcellular curvature, or buckling, can be energetically more favorable than larger scale deformations involving groups of cells. Inspired by recent experiments, we also find that local, subcellular curvature at cellcell interfaces emerges in a group of cells in response to the swelling of additional cells surrounding the group. Our framework, therefore, can account for a wider array of multicellular responses to constraints in the tissue environment.
 [259] arXiv:2404.03651 (replaced) [pdf, html, other]

Title: Multipartite edge modes and tensor networksComments: 49 pages, 78 pages with appendices, 19 figuresSubjects: High Energy Physics  Theory (hepth); Strongly Correlated Electrons (condmat.strel); Quantum Physics (quantph)
Holographic tensor networks model AdS/CFT, but so far they have been limited by involving only systems that are very different from gravity. Unfortunately, we cannot straightforwardly discretize gravity to incorporate it, because that would break diffeomorphism invariance. In this note, we explore a resolution. In low dimensions gravity can be written as a topological gauge theory, which can be discretized without breaking gaugeinvariance. However, new problems arise. Foremost, we now need a qualitatively new kind of "area operator," which has no relation to the number of links along the cut and is instead topological. Secondly, the inclusion of matter becomes trickier. We successfully construct a tensor network both including matter and with this new type of area. Notably, while this area is still related to the entanglement in "edge mode" degrees of freedom, the edge modes are no longer bipartite entangled pairs. Instead they are highly multipartite. Along the way, we calculate the entropy of novel subalgebras in a particular topological gauge theory. We also show that the multipartite nature of the edge modes gives rise to noncommuting area operators, a property that other tensor networks do not exhibit.
 [260] arXiv:2404.19022 (replaced) [pdf, other]

Title: Mobility and Threshold Voltage Extraction in Transistors with GateVoltageDependent Contact ResistanceComments: Corrected values tabulated in Figure 2d (surrounding discussion/conclusions unchanged); updated discussion surrounding Monte Carlo approach for error propagation; corrected typosSubjects: Applied Physics (physics.appph); Other Condensed Matter (condmat.other)
The mobility of emerging (e.g., twodimensional, oxide, organic) semiconductors is commonly estimated from transistor currentvoltage measurements. However, such devices often experience contact gating, i.e., electric fields from the gate modulate the contact resistance during measurements, which can lead conventional extraction techniques to estimate mobility incorrectly even by a factor >2. This error can be minimized by measuring transistors at high gatesource bias, $V_\mathrm{gs}$, but this regime is often inaccessible in emerging devices that suffer from high contact resistance or early gate dielectric breakdown. Here, we propose a method of extracting mobility in transistors with gatedependent contact resistance that does not require operation at high $V_\mathrm{gs}$, enabling accurate mobility extraction even in emerging transistors with strong contact gating. Our approach relies on updating the transfer length method (TLM) and can achieve <10% error even in regimes where conventional techniques overestimate mobility by >2$\times$.
 [261] arXiv:2405.02138 (replaced) [pdf, html, other]

Title: XtalOpt Version 13: MultiObjective Evolutionary Search for Novel Functional MaterialsSubjects: Computational Physics (physics.compph); Materials Science (condmat.mtrlsci)
Version 13 of XtalOpt, an evolutionary algorithm for crystal structure prediction, is now available for download from the CPC program library or the XtalOpt website, this https URL. In the new version of the XtalOpt code, a general platform for multiobjective global optimization is implemented. This functionality is designed to facilitate the search for (meta)stable phases of functional materials through minimization of the enthalpy of a crystalline system coupled with the simultaneous optimization of any desired properties that are specified by the user. The code is also able to perform a constrained search by filtering the parent pool of structures based on a userspecified feature, while optimizing multiple objectives. Here, we present the implementation and various technical details, and we provide a brief overview of additional improvements that have been introduced in the new version of XtalOpt.
 [262] arXiv:2405.04508 (replaced) [pdf, html, other]

Title: Synthetic magnetism enhanced mechanical squeezing in Brillouin optomechanical systemComments: 9 pages, 7 figures. Comments are welcome!Subjects: Quantum Physics (quantph); Mesoscale and Nanoscale Physics (condmat.meshall)
We propose a scheme to generate large amount of mechanical squeezing, far beyond the $\rm{3dB}$ limit, which is based on synthetic magnetism in optomechanical system that hosts a Backward Stimulated Brillouin Scattering (BSBS) process. Our benchmark system consists of an acoustic mode coupled to two optical modes through the BSBS process, and a Duffing mechanical oscillator that couples to the same optical modes through the standard optomechanical radiation pressure. The synthetic magnetism comes from the modulation of the mechanical coupling between the acoustic and the mechanical mode. When there is no synthetic magnetism, a given amount of mechanical squeezing is generated in the system. This squeezing is mainly dependent on the BSBS process, and it is fragile against thermal noise. By switching on the synthetic magnetism, the degree of the generated squeezing is greatly enhanced and goes far beyond the limit of the $\rm{3dB}$. This large magnetism induced squeezing persists even when there is no BSBS process in the system. Moreover, this generated squeezing is robust enough against thermal noise in comparison to the one induced when the synthetic magnetism is off. Furthermore, both the mechanical variance squeezing and effective phonon number exhibit series of peaks and dips depending on the phase modulation of the mechanical coupling. This oscillatory feature is reminiscent of a sudden death and revival of squeezing phenomenon, which can be used to maintain a desired magnitude of squeezing by tuning this phase. Our proposal provides a path toward a flexible scheme that generates large amount of squeezing, far beyond the $\rm{3dB}$ limit. Such a generated squeezed states can be used for quantum applications including quantum information processing, quantum sensing and metrology, and quantum computing.
 [263] arXiv:2405.05388 (replaced) [pdf, other]

Title: The Asymptotic Behavior of the Mayer Series Coefficients for a Dimer Gas on a Rectangular LatticeComments: 11 pages, ALL NEW and COMELYSubjects: Mathematical Physics (mathph); Statistical Mechanics (condmat.statmech)
This paper continues and complements the research in the earlier version of this paper (essentially Part 3 and Part 4 herein.) We now assume as suggested at the end of Part 4 that $b(n)$ is asymptotically of the form in eq.(A1).
\begin{equation}\label{A1} \tag{A1}
b(n) \sim \exp{( k_{1} n + k_{0} ln(n) + \frac{k_{1}}{n} + \frac{k_{2}}{n^{2}}...)} \end{equation} Using the details of the six approximations used in Part 3, corresponding to the six values of $r$, $ 1 \leq r \leq 6$, in dimensions $d$ equal $2$. $3$, $5$, $11$ and $20$ we find in Part 1 an approximate value for the right side of eq.(A1) keeping the three terms in the exponent in $k_{1}$, $k_{0}$, and $k_{1}$. In the range $5 \leq n \leq 20$ the two sides of eq.(A1) may be said to agree roughly to 5 parts per 100. ( With an appropriate choice of a constant of proportionality. )
In Part 2 an approximation is found keeping the term in $k_{2}$ also that may be said to agree to 5 parts in 1000 in the range $8 \leq n \leq 20$. Not only is it amazing that the relation in eq.(A1) seems to hold, it is equally amazing that it is so accurate for such small values of $n$.  [264] arXiv:2405.12243 (replaced) [pdf, html, other]

Title: The KohnLuttinger Effect in Dense Matter and its Implications for Neutron StarsComments: 34 pages, 11 figuresSubjects: Nuclear Theory (nuclth); High Energy Astrophysical Phenomena (astroph.HE); Superconductivity (condmat.suprcon)
Repulsive shortrange interactions can induce pwave attraction between fermions in dense matter and lead to Cooper pairing at the Fermi surface. We investigate this phenomenon, wellknown as the KohnLuttinger effect in condensed matter physics, in dense matter with strong shortrange repulsive interactions. We find that repulsive interactions required to stabilize massive neutron stars can induce pwave pairing in neutron and quark matter. When massive vector bosons mediate the interaction between fermions, the induced interaction favors Cooper pairing in the 3P2 channel. For the typical strength of the interaction favored by massive neutron stars, the associated pairing gaps in neutrons can be in the range of 10 keV to 10 MeV. Strong and attractive spinorbit and tensor forces between neutrons can result in repulsive induced interactions that greatly suppress the 3P2 pairing gap in neutron matter. In quark matter, the induced interaction is too small to result in pairing gaps of phenomenological relevance.
 [265] arXiv:2406.11957 (replaced) [pdf, html, other]

Title: Linear response theory for cavity QED materialsComments: No significant changes in second version, just a cross reference with another preprintSubjects: Quantum Physics (quantph); Strongly Correlated Electrons (condmat.strel)
We present a rigorous framework for linear response theory in cavity QED materials. Our approach leverages the collective coupling between light and matter, drawing parallels with largeN theories in quantum field theory. We derive closed formulas for various responses of both the cavity and the matter. Our theory is validated by recovering established results for the Dicke model and the Quantum Hall Effect. Additionally, we discover novel excitations in quantum magnets, where the cavity binds magnon pairs into localized states.
 [266] arXiv:2406.11971 (replaced) [pdf, html, other]

Title: Cavity QED materials: Comparison and validation of two linear response theories at arbitrary lightmatter coupling strengthsComments: No significant changes in second version, just a cross reference with another preprintSubjects: Quantum Physics (quantph); Strongly Correlated Electrons (condmat.strel)
We develop a linear response theory for materials collectively coupled to a cavity that is valid in all regimes of lightmatter coupling, including symmetrybroken phases. We present and compare two different approaches. First, using a coherent path integral formulation for the partition function to obtain thermal Green functions. This approach relies on a saddle point expansion for the action, that can be truncated in the thermodynamic limit. Second, by formulating the equations of motion for the retarded Green functions and solving them. We use a meanfield decoupling of highorder Green functions in order to obtain a closed, solvable system of equations. Both approaches yield identical results in the calculation of response functions for the cavity and material. These are obtained in terms of the bare cavity and material responses. In combination, the two techniques clarify the validity of a meanfield decoupling in correlated lightmatter systems and provide complementary means to compute finitesize corrections to the thermodynamic limit. The theory is formulated for a general model that encompasses most of the systems typically considered in the field of cavity QED materials, within a longwavelength approximation. Finally, we provide a detailed application of the theory to the Quantum Hall effect and to a collection of magnetic models. We validate our predictions against analytical and finitesize exactdiagonalization results.