CMP Journal 2025-09-22
Statistics
Nature: 1
Nature Materials: 1
Physical Review Letters: 5
arXiv: 48
Nature
Decoding the redox behaviour of copper in Ullmann-type coupling reactions
Original Paper | Catalytic mechanisms | 2025-09-21 20:00 EDT
Yongrui Luo, Yuli Li, Botao Wu, Guangyu Wang, Jian Wu, Sheng-Ye Zhang, K. N. Houk, Qilong Shen
The copper-catalysed functionalization of aryl halides is one of the most preferred methods for the formation of carbon-carbon and carbon-heteroatom bonds.1 Yet, the redox behaviour of the copper species in the catalytic cycle remains elusive and a subject of considerable debate.2 We report experimental and theoretical mechanistic investigations into the reaction of a well-defined Cu(I) complex with an electron-poor aryl iodide, which leads to the formation of an isolable Cu(III)-aryl complex, that subsequently reductively eliminates to forge a C(sp2)-CF3 bond. Our integrated experimental and theoretical findings indicate that the process proceeds through a redox sequence of Cu(I)/Cu(III)/Cu(II)/Cu(III)/Cu(I). Additionally, we managed to interrupt this sequence by temperature control and captured the reactivity of the copper species through various spectroscopic methods, facilitating in-depth mechanistic analysis. These findings shed light on the intricate behaviour of copper species and challenge the traditional mechanistic proposal for the reaction of Cu(I) with aryl iodide, thus providing fresh perspectives into the mechanistic aspect of the copper-catalysed coupling reactions.
Catalytic mechanisms, Homogeneous catalysis
Nature Materials
Structural constraint integration in a generative model for the discovery of quantum materials
Original Paper | Magnetic properties and materials | 2025-09-21 20:00 EDT
Ryotaro Okabe, Mouyang Cheng, Abhijatmedhi Chotrattanapituk, Manasi Mandal, Kiran Mak, Denisse Córdova Carrizales, Nguyen Tuan Hung, Xiang Fu, Bowen Han, Yao Wang, Weiwei Xie, Robert J. Cava, Tommi S. Jaakkola, Yongqiang Cheng, Mingda Li
Billions of organic molecules have been computationally generated, yet functional inorganic materials remain scarce due to limited data and structural complexity. Here we introduce Structural Constraint Integration in a GENerative model (SCIGEN), a framework that enforces geometric constraints, such as honeycomb and kagome lattices, within diffusion-based generative models to discover stable quantum materials candidates. SCIGEN enables conditional sampling from the original distribution, preserving output validity while guiding structural motifs. This approach generates ten million inorganic compounds with Archimedean and Lieb lattices, over 10% of which pass multistage stability screening. High-throughput density functional theory calculations on 26,000 candidates shows over 95% convergence and 53% structural stability. A graph neural network classifier detects magnetic ordering in 41% of relaxed structures. Furthermore, we synthesize and characterize two predicted materials, TiPd0.22Bi0.88 and Ti0.5Pd1.5Sb, which display paramagnetic and diamagnetic behaviour, respectively. Our results indicate that SCIGEN provides a scalable path for generating quantum materials guided by lattice geometry.
Magnetic properties and materials, Theory and computation
Physical Review Letters
Emergence of Unitarity and Locality from Hidden Zeros at One-Loop Order
Article | Particles and Fields | 2025-09-22 06:00 EDT
Jeffrey V. Backus and Laurentiu Rodina
Recent investigations into the geometric structure of scattering amplitudes have revealed the surprising existence of "hidden zeros": secret kinematic loci where tree-level amplitudes in theory, the nonlinear sigma model (NLSM), and Yang-Mills theory vanish. In this Letter, we propose the ext…
Phys. Rev. Lett. 135, 131601 (2025)
Particles and Fields
Precision Measurement of Spin-Dependent Dipolar Splitting in $^{6}\mathrm{Li}$ $p$-Wave Feshbach Resonances
Article | Atomic, Molecular, and Optical Physics | 2025-09-22 06:00 EDT
Shuai Peng, Sijia Peng, Lijun Ren, Shaokun Liu, Bin Liu, Jiaming Li, and Le Luo
The magnetic dipolar splitting of a -wave Feshbach resonance is governed by the spin-orbital configuration of the valence electrons in the triplet molecular state. We perform high-resolution trap-loss spectroscopy on ultracold atoms to resolve this splitting with sub-milligauss precision. By co…
Phys. Rev. Lett. 135, 133401 (2025)
Atomic, Molecular, and Optical Physics
Spontaneous Emission Decay and Excitation in Photonic Time Crystals
Article | Atomic, Molecular, and Optical Physics | 2025-09-22 06:00 EDT
Jagang Park, Kyungmin Lee, Ruo-Yang Zhang, Hee-Chul Park, Jung-Wan Ryu, Gil Young Cho, Min Yeul Lee, Zhaoqing Zhang, Namkyoo Park, Wonju Jeon, Jonghwa Shin, C. T. Chan, and Bumki Min
A material whose dielectric properties vary in time could produce exotic light-emission phenomena in a nearby atom, theorists predict.
Phys. Rev. Lett. 135, 133801 (2025)
Atomic, Molecular, and Optical Physics
Turbulence without Walls: Whither the Zeroth Law of Turbulence?
Article | Physics of Fluids, Earth & Planetary Science, and Climate | 2025-09-22 06:00 EDT
Kartik P. Iyer, Theodore D. Drivas, Gregory L. Eyink, and Katepalli R. Sreenivasan
Direct numerical simulations of incompressible homogeneous and isotropic turbulence in a periodic box show that the mean dissipation rate of the kinetic energy approaches zero as the Reynolds number goes to infinity, violating the classical zeroth law of turbulence but compatible with the Kolmogorov 4/5 law.
Phys. Rev. Lett. 135, 134001 (2025)
Physics of Fluids, Earth & Planetary Science, and Climate
New Pathway to Impact Ionization in a Photoexcited One-Dimensional Ionic Hubbard Model
Article | Condensed Matter and Materials | 2025-09-22 06:00 EDT
Zhenyu Cheng, Li Yang, Xiang Hu, Hantao Lu, Zhongbing Huang, and Liang Du
Using the time-dependent Lanczos method, we study the nonequilibrium dynamics of the half-filled one-dimensional ionic Hubbard model, deep within the Mott insulating regime, under the influence of a transient laser pulse. In equilibrium, increasing the staggered potential in the Mott regime reduces …
Phys. Rev. Lett. 135, 136501 (2025)
Condensed Matter and Materials
arXiv
Surface diffusion: The intermediate scattering function seen as a characteristic function of probability theory
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-22 20:00 EDT
E. E. Torres-Miyares, S. Miret-Artés
In surface diffusion, one of the key observables is the so-called intermediate scattering function which is measured directly from the surface technique called Helium spin echo. In this work, we show that this function can be seen as a characteristic function of probability theory. From the characteristic function, the moments and cumulants of the probability distribution function of the position of the adsorbate are straightforward obtained in an analytical way; in particular, the second order which is related to the diffusion coefficient. In order to illustrate this simple theory, we have focused on the incoherent tunneling of H and D on a Pt(111) surface where only jumps between nearest neighbor sites have been reported experimentally. Finally, an extension to jumps to more than nearest neighbors has also been considered.
Statistical Mechanics (cond-mat.stat-mech)
1 figures
Quantum oscillations in two-dimensional hole gases with competing cyclotron and Zeeman energy
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-22 20:00 EDT
Davide Costa, Lucas E. A. Stehouwer, Davide Degli Esposti, Giordano Scappucci
Evaluation of critical bandstructure and quantum transport parameters in two-dimensional systems is challenging when competition emerges among different energy scales shaping quantum oscillations in a magnetic field. Here we overcome this challenge in low-disorder strained germanium quantum wells by evaluating self-consistently effective mass, g-factor, and quantum lifetime. As a result, we estimate a quantum mobility of 133(3)$ \times$ 10$ ^3$ cm$ ^2$ /Vs, setting a benchmark for 2D holes in group IV semiconductors. The high quality of the hole gas if further highlighted by observing clean fractional quantum Hall states at low magnetic field and low density.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Electrodynamics of carbon nanotubes with non-local surface conductivity
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-22 20:00 EDT
Tomer Berghaus, Touvia Miloh, Oded Gottlieb, Gregory Ya. Slepyan
A new framework that can be utilized for the electrodynamics of carbon nanotubes (CNTs) with non-local surface conductivity (spatial dispersion) is presented. The model of non-local conductivity is developed on the basis of the Kubo technique applied to the Dirac equation for pseudospins. As a result, the effective boundary conditions for the electromagnetic (EM) field on a CNT surface are formulated. The dispersion relation for the eigenmodes of an infinitely long CNT is obtained and analyzed. It is shown that due to nonlocality, a new type of eigenmodes are created that disappear in the local conductivity limit. These eigenmodes should be properly accounted for in the correct formulation of the CNT end conditions for the surface current, which are manifested in the EM-field scattering problem. Additional boundary conditions that consider nonlocality effects are also formulated based on the exact solution obtained for the surface current by means of using the Wiener-Hopf (WH) technique for a semi-infinite CNT. The scattering pattern of the EM-field is simulated by a finite-length model of a CNT, using a numerically solved integral equation for the surface current density and its approximate analytical solution. Thus, the scattering field of a CNT prevailing in the wide frequency range from THz to infrared light is analytically solved and analyzed. The newly obtained results are then utilized for determining the optical forces exerted on a CNT of finite length. Potential applications for the design of nanoantennas and other electronic devices, including pointing out some future directions, are also discussed.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
47 pages, 10 figures
Absence of Andreev Bound States in Noncentrosymmetric Superconductor PbTaSe$_2$ under Hydrostatic Pressures
New Submission | Superconductivity (cond-mat.supr-con) | 2025-09-22 20:00 EDT
Yu-qing Zhao, Zhi-fan Wu, Hai-yan Zuo, Wei-ming Lao, Yao He, Hai Wang, Ling-xiao Zhao, Ying-hui Sun, Huai-xin Yang, Geng-fu Chen, Cong Ren
Noncentrosymmetric superconductor PbTaSe$ _2$ , hosting bulk nodal-line fermions (Phys. Rev. B. 89, 020505) and spin-helical surface states (Nature Communication 7, 10556), represents a prime candidate for realizing topological superconductivity and Majorana bound states (MBS). However, the definitive experimental signature of MBS in this system has thus far remained elusive. Here we provide a comprehensive investigation of its superconducting properties under hydrostatic pressure. Combining Andreev reflection spectroscopy and temperature-dependent resistance measurements, we identify a separated surface-like superconductivity from the bulk one at a critical pressure $ P_c$ . The superconducting surface state demonstrate an $ s$ -wave pairing state with a strong coupling strength. Under magnetic fields, the absence of zero-bias conductance peak in the pressurized point-contact Andreev reflection spectrum. Our findings imposes a constraint on the theoretical proposals for realizing Majorana bound states in noncentrosymmetric superconductors.
Superconductivity (cond-mat.supr-con)
Dynamics of quantized vortices under quasi-periodic boundary conditions
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-09-22 20:00 EDT
Fabio Magistrelli, Marco Antonelli
The Gross-Pitaevskii equation is widely used for vortex dynamics, but finite domains with hard walls or confining potentials distort bulk behavior through vortex-image effects or induced flows. Periodic boundaries reduce wall artifacts yet cannot realize finite net vorticity because of topological obstruction, so bulk simulations with non-zero circulation are typically unavailable. Hence, we impose quasi-periodic boundary conditions that keep the superfluid’s density periodic while enforcing phase windings consistent with a net prescribed total vorticity. This setting conserves the net number of vortices and enables long-time tracking of vortex trajectories in settings that finite containers cannot capture. This allows us to study vortex depinning and nucleation leading to the creation of Kármán vortex streets and the creation of perfectly periodic vortex arrays. The framework also provides a toy model for studying vortex dynamics in the bulk of neutron stars, free of possible limitations induced by confining potentials.
Quantum Gases (cond-mat.quant-gas), High Energy Astrophysical Phenomena (astro-ph.HE), Nuclear Theory (nucl-th)
16 pages, 15 figures. Comments welcome
Electronic Crystal Phases in the Presence of Non-Uniform Berry Curvature and Tunable Berry Flux: The $λ_N$-Jellium model
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-22 20:00 EDT
Félix Desrochers, Joe Huxford, Mark R. Hirsbrunner, Yong Baek Kim
Recent experiments on multilayer graphene systems have rekindled interest in electronic crystal phases in two dimensions – but now for phases enriched by non-trivial quantum geometry. In this work, we introduce a simple continuum model with tunable Berry curvature distribution and total flux, enabling systematic study of crystallization in geometrically nontrivial bands. In the noninteracting limit, the addition of a C6-symmetric periodic potential yields a rich phase diagram, for which we provide several analytical insights. Notably, we derive a general formula for the Chern number in the weak-potential regime that is broadly applicable to single-band projected models. Removing the periodic potential and treating Coulomb interactions self-consistently at the Hartree-Fock level, the resulting phase diagrams host a variety of crystalline states, including anomalous Hall crystals, halo Wigner crystals in which localized electrons spontaneously acquire orbital angular momentum leading to depleted electron occupation at the zone center, and a novel halo anomalous Hall crystal that combines these properties with a finite Chern number. We identify why these phases are energetically favorable through analytical and energetic considerations. Our results provide insight into the interplay between crystallization and band geometry, while also offering a simple toy model amenable to numerical methods beyond mean-field.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
22 + 16 pages, 9 + 4 figures
Entropic balance with feedback control: information equalities and tight inequalities
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-22 20:00 EDT
Natalia Ruiz-Pino, Antonio Prados
We consider overdamped physical systems evolving under a feedback-controlled fluctuating potential and in contact with a thermal bath at temperature $ T$ . A Markovian description of the dynamics, which keeps only the last value of the control action, is advantageous – both from the theoretical and the practical side – for the entropy balance. Novel second-law equalities and bounds for the extractable work are obtained, the latter being both tighter and easier to evaluate than those in the literature based on the whole chain of controller actions. The Markovian framework also allows us to prove that the bound for the extractable work that incorporates the unavailable information is saturated in a wide class of physical systems, for error-free measurements. These results are illustrated in a model system. For imperfect measurements, there appears an interval of measurement uncertainty, including the point at which work ceases to be extracted, where the new Markovian bound is tighter than the unavailable information bound.
Statistical Mechanics (cond-mat.stat-mech)
7 pages, 4 figures, supplemental material as ancillary file
Training thermodynamic computers by gradient descent
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-22 20:00 EDT
We show how to adjust the parameters of a thermodynamic computer by gradient descent in order to perform a desired computation at a specified observation time. Within a digital simulation of a thermodynamic computer, training proceeds by maximizing the probability with which the computer would generate an idealized dynamical trajectory. The idealized trajectory is designed to reproduce the activations of a neural network trained to perform the desired computation. This teacher-student scheme results in a thermodynamic computer whose finite-time dynamics enacts a computation analogous to that of the neural network. The parameters identified in this way can be implemented in the hardware realization of the thermodynamic computer, which will perform the desired computation automatically, driven by thermal noise. We demonstrate the method on a standard image-classification task, and estimate the thermodynamic advantage – the ratio of energy costs of the digital and thermodynamic implementations – to exceed seven orders of magnitude. Our results establish gradient descent as a viable training method for thermodynamic computing, enabling application of the core methodology of machine learning to this emerging field.
Statistical Mechanics (cond-mat.stat-mech), Machine Learning (cs.LG)
Higgs mode in superconducting Titanium nanostructures
New Submission | Superconductivity (cond-mat.supr-con) | 2025-09-22 20:00 EDT
Laurine Marian, Edouard Pinsolle, Samuel Houle, Maxime Durand-Gasselin, Christian Lupien, Bertrand Reulet
We report observations of Higgs modes in superconducting Titanium nanostructures at very low temperature. They appear as anomalies in the microwave complex impedance of the samples revealed by the presence of a dc supercurrent. By varying the sample geometry and contact material, we probe how the Higgs modes are sensitive to the dimensionality of superconductivity, the penetration of the dc and ac current densities in the sample and the dissipation in the contacts.
Superconductivity (cond-mat.supr-con), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Competing Supramolecular Structures: Dielectric and Rheological Spectroscopy on Glycerol/Propanol Mixtures
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-22 20:00 EDT
Significant progress has been made in recent years in understanding the dynamics of pure hydrogen-bonded systems by analyzing the spectral shape of various susceptibilities. Monohydroxy- and polyalcohols are currently considered to form transient supramolecular hydrogen-bonded structures in the form of chains, rings, and networks. This complex dynamic behavior has been identified in network-forming glycerol and chain-forming propanol by combining dielectric and light-scattering spectra. We apply these concepts to study the combined dielectric and shear rheological spectral shape of glycerol/propanol mixtures. Glycerol differs from propanol by having two additional hydroxy groups, which leads to significant differences in melting temperatures($ \Delta T_{\textbf{m}}$ ,=,291,K,-,147,K,=,143,K) and glass transition temperatures ($ \Delta T_{\textbf{g}}$ ,=,190,K-,98,K,=,92,K). The strong difference results in two distinct calorimetric glass transitions at a molar glycerol concentration of $ \chi_{gly}=0.3$ , as well as a change in the shear modulus $ G_{\infty}$ between $ \chi_{gly}=0.5$ and 0.7. Performing a comprehensive analysis of the three applied experimental techniques leads to the conclusion that dielectric spectroscopy monitors the evolution of supramolecular chain and network structures and that the mechanical properties depend heavily on the formed hydrogen-bonded network. A strong dynamical heterogeneity is observed and manifests itself in two distinguishable glass transitions in dielectric spectroscopy and calorimetry. The presented chain/network mixture is dynamically highly heterogeneous when compared to the rather narrow dynamical heterogeneity in the network/network mixture Water/Glycerol.
Soft Condensed Matter (cond-mat.soft)
Absence of skewness in the voltage fluctuations of a tunnel junction in the quantum regime
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-22 20:00 EDT
Clovis Farley, Bertrand Reulet
Current fluctuations in a tunnel junction have a remarkable property: On the one hand, their variance corresponds to vacuum fluctuations at low voltage bias $ V$ , when the electron energy $ eV$ is smaller than the photon detection energy $ hf$ . On the other hand, their skewness, i.e. their third moment, is frequency independent, equal to $ e^2I$ as if electron transport were simply Poissonian. We address the following question: Could it be that at low voltage, the vacuum fluctuations generated by the junction have a finite skewness, i.e. that the junction generates skewed vacuum ? To answer this question we calculate the effect of an arbitrary electromagnetic environment at zero temperature and show that the bispectrum of third moment of voltage fluctuations of any quantum conductor is always zero at frequencies larger than the voltage. We also show experimental data on tunnel junctions in the quantum regime that agree with our calculation.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
6 pages, 3 figures
Long-lived dynamics of the charge density wave in TiSe$_2$ observed by neutron scattering
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-22 20:00 EDT
K. Dharmasiri (1), S. S. Philip (1), D. Louca (1), S. A. Chen (2), M. D. Frontzek (2), Z. J. Morgan (2), C. Hua (3) ((1) Department of Physics, University of Virginia, Charlottesville, United States, (2) Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, United States, (3) Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, United States)
Time-resolved elastic neutron scattering combined with rapid laser heating was used to probe the charge density wave (CDW) state in 1T-TiSe$ _2$ , capturing both the melting and reformation of the CDW on long timescales and providing clues on the roles of phonons and excitons. With the laser source on, superlattice Bragg peaks such as (-1.5, -1.5, 1.5) observed below the CDW transition due to the new lattice periodicity, dissipate within 5 seconds, at a rate that is much slower than the sample’s thermal response to the heat wave propagation. Whereas the electronic ordering associated with the CDW phase is disrupted rapidly by the laser-induced heating, the periodic lattice distortion (PLD) exhibits a markedly slower evolution during the melting process. This delayed suppression of the PLD relative to the thermal response indicates that CDW melting proceeds through a nonthermal pathway, likely linked to the loss of superlattice phonons such as the soft mode at q = (0.5 ,0, 0.5 ).
Materials Science (cond-mat.mtrl-sci)
12 pages, 12 figures
Spectral Characterization of Wave Scattering at a Granular-Elastic Solid Interface: From Hyperbolic Wave Propagation to Near-Parabolic Diffusion
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-22 20:00 EDT
Joshua R. Tempelman, Chongan Wang, Alexander F. Vakakis
We present a method based on acoustic wavenumber imaging algorithms to quantify the spectral content of strongly nonlinear energy scattering of a propagating wavefront across the discrete-continuum interface of a 2D hybrid system composed of an ordered granular layer in contact with a thin elastic plate. We consider snapshots of the transmitted wavefront at given time instants, which are filtered across the wavenumber domain by applying the spatial Fourier Transform (FT), and then the filtered wavefields are transformed back to the spatial domain by inverse spatial FT. This yields a spectral decomposition of the given snapshots at varying center wavenumbers. Based on this postprocessing method, the scattering of the kinetic energy in the receiving medium (plate) can be studied in the wavenumber-time domain, proving a quantitative measure of the nonlinear scattering of the transmitted wavefront by the strongly nonlinear 2D granular layer. This postprocessing method enables the detailed quantitative study of the scattering and spectral energy redistribution of propagating wavepackets in elastic media with embedded linear or nonlinear layers or inclusions. In addition, we show that the spectral evolution of receiving plate with a granular interface exhibits diffusion-like behavior in the wavenumber domain, drawing an analogy between parabolic heat diffusion and classical hyperbolic elsatodynamic energy transport.
Statistical Mechanics (cond-mat.stat-mech)
18 pages, 11 figures
Förster transfer between quantum dots in a shared phonon environment: An exact approach, revealing the role of pure dephasing
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-22 20:00 EDT
Liubov S. Sirkina, Luke M. J. Hall, Amy Morreau, Wolfgang Langbein, Egor A. Muljarov
Förster resonance energy transfer has an important role in nature and technology, rendering its exact theoretical understanding significant. To this end, a system of two electronically decoupled quantum dots (QDs) is considered, interacting via dipole-dipole interaction and a common phonon bath. While the former leads to an oscillatory excitation transfer between the dots, the latter provide the dissipation resulting in directional Förster transfer. We present an exact microscopic treatment of the phonon-assisted transitions between hybridized exciton levels of the coupled QD system, going beyond the simple perturbative approaches commonly used in the literature. From our asymptotically exact results we extract population decay times $ T_1$ , dephasing times $ T_2$ , and resulting pure dephasing times $ T_2^\ast$ of the states. We compare this treatment with an analytical model based on Fermi’s golden rule, combining the most accurate elements of existing analytical treatments. The exact results show a significant deviation from this model in some parameter regimes, mainly due to the role of multi-phonon processes, which become important for comparable electron-phonon and dipolar coupling, realised at short distances between the QDs and at elevated temperatures.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
First-principles calculation of higher-order elastic constants from divided differences
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-22 20:00 EDT
Ruvini Attanayake, Umesh C. Roy, Abhiyan Pandit, Angelo Bongiorno
A method is presented to calculate from first principles the higher-order elastic constants of a solid material. The method relies on finite strain deformations, a density functional theory approach to calculate the Cauchy stress tensor, and a recursive numerical differentiation technique homologous to the divided differences polynomial interpolation algorithm. The method is applicable as is to any material, regardless its symmetry, to calculate elastic constants of, in principle, any order. Here, we introduce conceptual framework and technical details of our method, we discuss sources of errors, we assess convergence trends, and we present selected applications. In particular, our method is used to calculate elastic constants up to the 6$ ^{th}$ order of two crystalline materials with the cubic symmetry, silicon and gold. To demonstrate general applicability, our method is also used to calculate the elastic constants up to the 5$ ^{th}$ order of $ \alpha$ -quartz, a crystalline material belonging to the trigonal crystal system, and the second- and third-order elastic constants of kevlar, a material with an anisotropic bonding network. Higher order elastic constants computed with our method are validated against density functional theory calculations by comparing stress responses to large deformations derived within the continuum approximation.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
Symmetries and dynamics of quantum Hall bulk anyons in quadratic potentials
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-22 20:00 EDT
Preethi Basani, Varsha Subramanyan, Smitha Vishveshwara
We study two-particle coherent states and their dynamics in the lowest Landau level (LLL) under the influence of quadratic potentials. We focus on generalized coherent states that describe Abelian anyons in the LLL and are associated with the $ \mathfrak{su}(1,1)$ Lie algebra. We draw on parallels with quantum optics and symmetry properties of the coherent states considered here to analytically calculate quantities such as a bunching parameter, which depends on quantum statistics, as well as coherent state trajectories under the influence of generic quadratic potentials. Our results show that in unbounded saddle potentials, the bunching parameter governs the trajectories which show exponentially diverging behavior in a manner that depends on quantum statistics. In bounded elliptical potentials, the bunching parameter is oscillatory and its maximum magnitude depends on the eccentricity of the applied potential. We draw connections between our analyses and the key concepts that underlie anyon detection in recent experiments.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
6 pages, 3 figures
Machine-Learning Potentials for Efficient Simulations of Anisotropic Colloids
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-22 20:00 EDT
Simulating interactions between non-spherical colloidal particles is computationally challenging due to the complex dependency of forces and energies on their geometry. We introduce and evaluate both descriptor-based and end-to-end models for predicting interaction energies and forces. Then, we compare various descriptors coupled with different regression models, like Behler-Parinello descriptors, Smooth Overlap of Atomic Positions, and neuroevolution potential, as well as multiple end-to-end models, namely SchNet, DimeNet, and DimeNet++. Among these, the neuroevolution potential (NEP) offers an optimal balance between accuracy and computational efficiency. NEP, originally developed for atomistic systems, represents interactions between rigid anisotropic bodies using point clouds, which enables the representation of any arbitrary shape. Molecular dynamics simulations using NEP, accurately reproduced structural properties across diverse particle shapes including cubes, tetrahedra, pentagonal bipyramids, and twisted cylinders, while achieving roughly up to an order-of-magnitude speedup over other methods. Additionally, we show that the extension of the method to multi-face shapes with different interactions on their surface is straightforward. We used a twisted cylinder, which lacked any point group symmetry, to demonstrate the flexibility and accuracy of NEP. Our approach enables scalable simulations of complex colloidal systems and can potentially help to facilitate efficient studies on shape dependent interactions and phase behavior in the future.
Soft Condensed Matter (cond-mat.soft)
Magnetoelastic Coupling-Driven Chiral Spin Textures: A Skyrmion-Antiskyrmion-Like Array
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-22 20:00 EDT
We theoretically demonstrate that sufficiently strong magnetoelastic coupling can change the ground state of otherwise uniform spin systems to chiral spin configurations. More specifically, we show that, a periodic array of chiral spin textures can spontaneously emerge in a two-dimensional ferromagnetic system on a substrate-even in the absence of Dzyaloshinskii-Moriya interaction. The resulting spin texture resembles a skyrmion-antiskyrmion lattice, characterized by alternating scalar spin chirality and a nonuniform but sign-preserving out-of-plane spin profile. Our analysis reveals that such patterns form naturally when the magnetoelastic interaction is sufficiently strong, while the coupling between flexural phonons and the substrate is sufficiently weak. These findings uncover a previously unexplored mechanism for chiral spin texture formation driven purely by magnetoelastic coupling, signaling at potential utilities of materials with strong magnetoelastic responses.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
5 pages, 5 figures
Evidence for Half-Quantized Chiral Edge Current in a C = 1/2 Parity Anomaly State
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-22 20:00 EDT
Deyi Zhuo, Bomin Zhang, Humian Zhou, Han Tay, Xiaoda Liu, Zhiyuan Xi, Chui-Zhen Chen, Cui-Zu Chang
A single massive Dirac surface band is predicted to exhibit a half-quantized Hall conductance, a hallmark of the C = 1/2 parity anomaly state in quantum field theory. Experimental signatures of the C = 1/2 parity anomaly state have been observed in semi-magnetic topological insulator (TI) bilayers, yet whether it supports a half-quantized chiral edge current remains elusive. Here, we observe a robust half-quantized Hall conductance plateau in a molecular beam epitaxy (MBE)-grown asymmetric magnetic TI trilayer under specific in-plane magnetic field regimes, corresponding to the C = 1/2 parity anomaly state. Within this state, both nonlocal and nonreciprocal transport signals are greatly enhanced, which we identify as direct evidence for a half-quantized chiral edge current localized at the boundary of the top gapped surface. Our numerical simulations demonstrate that this half-quantized chiral edge channel is the essential carrier of the observed half-quantized Hall conductance plateau, analogous to the quantized chiral edge channel in the C = 1 quantum anomalous Hall state. Our results provide experimental evidence for the half-quantized chiral edge transport in a C = 1/2 parity anomaly state. This work establishes asymmetric magnetic TI trilayers as a platform for probing single Dirac fermion physics and paves the way to explore a series of exciting phenomena in the C = 1/2 parity anomaly state, including the topological magnetoelectric effect and quantized magneto-optical response.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
19 pages, 4 figures, comments are welcome
Dynamic polarization of nuclear spins by optically-oriented electrons and holes in lead halide perovskite semiconductors
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-22 20:00 EDT
Mladen Kotur, Pavel S. Bazhin, Kirill V. Kavokin, Nataliia E. Kopteva, Dmitri R. Yakovlev, Dennis Kudlacik, Manfred Bayer
A theory of dynamic polarization of the nuclear spin system via optically-oriented charge carriers in lead halide perovskites is developed and compared with the experiments performed on a FA$ _{0.9}$ Cs$ _{0.1}$ PbI$ _{2.8}$ Br$ _{0.2}$ crystal. The spin Hamiltonians of the electron and hole hyperfine interaction with the nuclear spins of lead and halogen are derived. The hyperfine interaction of the halogen spins with charge carriers is shown to be anisotropic and depending on the position of the halogen nucleus in the cubic elementary cell. The quadrupole splitting is absent for the lead spins, but plays an important role for the halogen spins and affects their dynamic polarization by charge carriers. The Overhauser fields of the dynamically polarized nuclei are calculated as functions of the tilting angle of an external magnetic field and compared with the experimentally measured angular dependence of the Hanle effect. The comparison of the theoretical model with the experimental data reveals an enhanced spin polarization of the lead nuclei, whose mean spin exceeds several times the mean spins of localized electrons and holes. This unexpectedly strong spin polarization is explained by the interaction of the lead nuclei with excitons having a high degree of spin orientation due to their short lifetime after excitation by circularly-polarized light. The dynamic polarization of the quadrupole-split halogen spins manifests itself via the magnetic field they produce at the lead nuclei. This field maintains the magnetization of the lead nuclei at zero external magnetic field. The dynamics of the nuclear spin polarization is measured under optical pumping and in the dark, yielding a nuclear spin-lattice relaxation time on the order of 10 seconds.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Improving Spectral Resolution from Real-time Evolution for Correlated Systems
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-22 20:00 EDT
Ta Tang, Chunjing Jia, Brian Moritz, Thomas P. Devereaux
The quality of numerically simulated spectra using real-time evolution methods for strongly correlated systems is affected by both the length of simulation time and the system size, limiting resolution in both frequency and momentum. In this work, we propose a computationally cheap, linear autoregressive machine learning-based framework to extend short-time and distance results over a wider range. We demonstrate the proposed method to extend the lesser Green’s function for both the Hubbard model and the much more computationally challenging Hubbard-extended Holstein model. This technique significantly improves both the frequency and momentum resolution of the single-particle removal spectrum $ \mathcal{A}(k,\omega)$ , allowing observation of otherwise obscured spectral features due to electron-phonon coupling.
Strongly Correlated Electrons (cond-mat.str-el), Disordered Systems and Neural Networks (cond-mat.dis-nn)
6 pages, 3 figures
Spin-Orbital Altermagnetism
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-22 20:00 EDT
Zi-Ming Wang, Yang Zhang, Song-Bo Zhang, Jin-Hua Sun, Elbio Dagotto, Dong-Hui Xu, Lun-Hui Hu
Altermagnet is a newly discovered magnetic phase, characterized by non-relativistic spin-splitting that has been experimentally observed. Here, we introduce a framework dubbed {\it spin-orbital altermagnetism} to achieve spin-orbital textures in altermagnetic materials. We identify two distinct classes of spin-orbital altermagnetism: intrinsic and extrinsic. The intrinsic type emerges from symmetry-compensated magnetic orders with spontaneously broken parity-time symmetry, while the extrinsic type stems from translational-symmetry breaking between sublattices, as exemplified by the Jahn-Teller-driven structural phase transition. In addition to directly measuring the spin-orbital texture, we propose spin conductivity and spin-resolved orbital polarization as effective methods for detecting these altermagnets. Additionally, a symmetry-breaking mechanism induces weak spin magnetization, further revealing the peculiar feature of spin-orbital altermagnetism. We also utilize the staggered susceptibility to illustrate a potential realization of this phase in a two-orbital interacting system. Our work provides a new platform to explore spin-orbital locked physics, extending the materials classes that may display complex spin textures from the standard $ 4d-5d$ compounds to $ 3d$ compounds.
Strongly Correlated Electrons (cond-mat.str-el)
PRL in press
Diffusion of gravitactic chiral active Brownian particles in an asymmetric channel
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-22 20:00 EDT
Narender Khatri, Vikas Sharma, Anton F. Burnet, Suneet Kumar Awasthi
The diffusion of micro- and nano-swimmers in a fluid, confined within irregular structures that impose entropic barriers, is often modeled using overdamped active Brownian dynamics, where viscous effects are paramount and inertia is negligible. Here, we numerically investigate the diffusive behavior of chiral self-propelled particles in a two-dimensional asymmetric channel subjected to an external torque arising from a gravitational field. We reveal the emergence of resonant diffusion when the external torque $ \omega$ approaches the intrinsic angular velocity $ \omega_{0}$ of particles. This resonance manifests as a pronounced accumulation of particles near the upper-left corner of the channel, accompanied by an enhanced peak in the effective diffusion coefficient. In particular, it is observed only for low rotational diffusion rates and does not persist beyond moderate values of $ \omega_{0}$ . Prominent transport features, such as rectification at low values of $ \omega$ , a monotonic increase in average velocity with $ \omega$ , and a nonmonotonic response of transport characteristics (average velocity and effective diffusion coefficient) as a function of the rotational diffusion rate near the resonance point, are explained. Furthermore, we show that the transport characteristics depend strongly on the aspect ratio of the channel. For instance, the enhanced diffusion peak becomes more pronounced with increasing aspect ratio, and the average velocity saturates at higher values for wider bottleneck openings. It is conceivable that these findings have a great potential for developing microfluidic and lab-on-a-chip devices for particle separation, targeted drug delivery, and advanced active materials.
Soft Condensed Matter (cond-mat.soft)
18 pages, 7 figures
Intrinsic Berry Curvature Driven Anomalous Hall and Nernst Effect in Co$_2$MnSn
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-22 20:00 EDT
Bishal Das, Arnab Bhattacharya, Amit Chanda, Chanchal K. Barman, Jadupati Nag, Hariharan Srikanth, Aftab Alam, I. Das
Magnetic topological semimetals often exhibit unusual electronic and thermal transport due to nontrivial bulk band crossings, enabling simultaneous realization of large anomalous Hall and Nernst conductivities ($ \sigma_{xy}$ and $ \alpha_{xy}$ ). Here, a comprehensive experimental and theoretical study of the anomalous transport properties of ferromagnetic Co$ 2$ MnSn is reported. First-principles calculations reveal topological Weyl points producing significant Berry curvature, driving dominant intrinsic anomalous Hall/Nernst effects. Electronic and thermal transport measurements demonstrate robust anomalous transport with substantial conductivity values that persist at room temperature ($ \sigma{xy}\sim$ 500 S/cm, $ \alpha_{xy}\sim$ 1.3 A/m/K). We also show how the chemical substitution (via tuning Fermi level) can boost these effects (up to $ \sigma_{xy}\sim$ 1376 S/cm, $ \alpha_{xy}\sim$ 1.49 A/m/K at 150 K). These findings position Co$ _2$ MnSn as a compelling platform for exploring topological transport phenomena and advancing next-generation thermoelectric and spintronic technologies.
Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other), Strongly Correlated Electrons (cond-mat.str-el)
Bishal Das and Arnab Bhattacharya contributed equally to this work. 17 pages (11 pages main, 6 pages supplement), 11 figures (4 figures main, 7 figures supplement)
Correlation Effects on Magnetic Structure and Lattice Dynamics of LaMn$7$O${12}$: A First-Principles Study
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-22 20:00 EDT
Haeyoon Jung, Indukuru Ramesh Reddy, Bongjae Kim, Jiyeon Kim, Sooran Kim
LaMn$ _7$ O$ _{12}$ , a quadruple perovskite oxide (AA’$ _3$ B$ _4$ O$ _{12}$ -type), has attracted attention for its notable bifunctional activity in oxygen evolution and reduction reactions. Here, we systematically investigate the magnetic phase diagram and lattice dynamics of LaMn$ _7$ O$ _{12}$ using two density functional theory plus Hubbard U (DFT + U) approaches: the spin-density and the charge-only-density formalism. Phase diagram analysis as a function of U and J shows that both methods stabilize the experimentally observed antiferromagnetic (AFM) configuration (C-type AFM at the B-site and ferrimagnetic structure at the A’-site Mn ions) at U = 3.5 eV and J = 0.8 eV. These U and J values are consistent with those obtained from the constrained random phase approximation. Furthermore, we observe the dynamical stability of the AFM phase through phonon dispersion curves and analyze the Raman-active phonon modes. These results highlight the critical role of appropriate U and J parameters in accurately describing the properties of LaMn$ _7$ O$ _{12}$ .
Strongly Correlated Electrons (cond-mat.str-el)
Crystal Growth, Band Structure, Magnetism and Electrochemical Properties of Hexavalent Strontium Ruthenium Oxyhydroxide
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-22 20:00 EDT
Subham Naik, Soumili Dutta, Hiranmayee Senapati, Sweta Yadav, Subarna Ray, Jai Prakash, Rahul Sharma, Gohil S. Thakur
Ruthenates comprise an interesting class of materials with a wide range of extremely exciting properties, and thus the discovery of new stable ruthenates remains an active area of investigation. We report the crystal growth and comprehensive studies including crystal and electronic structure, magnetic and electrochemical properties of a hexavalent ruthenium oxyhydroxide Sr3Ru2O9H2 prepared through a low-temperature hydrothermal method. Single crystals and powder samples of this phase are isolated by optimising the Sr(OH)2 to KRuO4 ratio while maintaining a high base concentration. The new structure consists of a rare five-coordinated RuVI featuring isolated trigonal prisms and crystallising in a non-centrosymmetric tetragonal system. Isolated Ru polyhedra leading to a large spatial distance ~ 50 pm between the Ru metal centres render the compound paramagnetic despite strong antiferromagnetic correlation. Band structure calculation suggests a metal-like electronic ground state with mostly Ru d and O p orbitals contributing to the Fermi surface. The electrochemical performance of Sr3Ru2O9H2, though not as impressive as RuO2, remains relevant and is on par with other reported OER catalysts.
Materials Science (cond-mat.mtrl-sci)
28 pages including supplementary information
Direct observation of cation-dependent polarisation switching dynamics in fluorite ferroelectrics
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-22 20:00 EDT
Kousuke Ooe, Yufan Shen, Kazuki Shitara, Shunsuke Kobayashi, Yuichi Shimakawa, Daisuke Kan, Joanne Etheridge
Fluorite ferroelectrics are exciting candidates for next-generation non-volatile memory devices because their unique ferroelectric mechanism, which arises from unconventional oxygen displacements, permits ferroelectricity with minimal thickness constraints. However, the polarisation switching mechanism remains the subject of intense debate due to a limited understanding of the atomic-scale dynamics which are extremely challenging to detect and measure. Here, we observe directly the polarisation switching pathways by visualising oxygen site dynamics in ZrO2 and Hf0.5Zr0.5O2 freestanding membranes using an advanced atomic-column imaging technique-optimum bright-field scanning transmission electron microscopy. We observe that the 180- and 90-degree polarisation pathways involve different nonpolar intermediate states with distinct spatial scales. Coupled with density functional theory, we also reveal how different cation species in fluorite oxides impact the accessible polarisation switching pathways. Our atomic-level insights into the polarisation switching dynamics open new avenues for the advanced engineering of fluorite ferroelectric materials and resulting memory devices.
Materials Science (cond-mat.mtrl-sci)
Terahertz radiation induced attractive-repulsive Fermi polaron conversion in transition metal dichalcogenide monolayers
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-22 20:00 EDT
We present a theoretical study of terahertz radiation-induced transitions between attractive and repulsive Fermi polaron states in monolayers of transition metal dichalcogenides. Going beyond the simple few-particle trion picture, we develop a many-body description that explicitly accounts for correlations with the Fermi sea of resident charge carriers. We calculate the rate of the direct optical conversion process, showing that it features a characteristic frequency dependence near the threshold due to final-state electron-exciton scattering related to the trion correlation with the Fermi sea hole. Furthermore, we demonstrate that intense terahertz pulses can significantly heat the electron gas via Drude absorption enabling an additional, indirect conversion mechanism through collisions between hot electrons and polarons, which exhibits a strong exponential dependence on temperature. Our results reveal the important role of many-body correlations and thermal effects in the terahertz-driven dynamics of excitonic complexes in two-dimensional semiconductors.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other)
11 pages, 5 figures
Barrier Electrostatics and Contact Engineering for Ultra-Wide Bandgap AlGaN HFETs
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-22 20:00 EDT
Seungheon Shin, Can Cao, Jon Pratt, Yinxuan Zhu, Brianna A. Klein, Andrew Armstrong, Andrew A. Allerman, Siddharth Rajan
We report ultra-wide bandgap (UWBG) AlGaN heterostructure field-effect transistors (HFETs) exhibiting a high breakdown field (> 5.3 MV/cm) and a low contact resistance (~1.55 {\Omega}mm), tailored for high-power radiofrequency applications. A split-doped barrier architecture, employing two distinct doping concentrations, is shown to enhance both the breakdown field and contact resistance. This design enables a state-of-the-art combination of maximum drain current (487 mA/mm) and breakdown field, along with a high cutoff frequency of 7.2 GHz. These results demonstrate a viable pathway to push device performance toward the material limits while minimizing contact resistance in UWBG AlGaN HFETs, paving the way for next-generation high-power, high-frequency applications.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
11 pages, 10 figures
Ring polymers in two-dimensional melts double-fold around randomly branching “primitive shapes”
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-22 20:00 EDT
Mattia A. Ubertini, Angelo Rosa
Drawing inspiration from the concept of the “primitive path” of a linear chain in melt conditions, we introduce here a numerical protocol which allows us to detect, in an unambiguous manner, the “primitive shapes” of ring polymers in two-dimensional melts. Then, by analysing the conformational properties of these primitive shapes, we demonstrate that they conform to the statistics of two-dimensional branched polymers (or, trees) in the same melt conditions, in agreement with seminal theoretical work by Khokhlov, Nechaev and Rubinstein. Results for polymer dynamics in light of the branched nature of the rings are also presented and discussed.
Soft Condensed Matter (cond-mat.soft), Computational Physics (physics.comp-ph)
25 pages, 14 figures, submitted for publication
Unveiling Excitonic Insulator Signatures in Ta$\mathrm{2}$NiSe$\mathrm{5}$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-22 20:00 EDT
Nour Maraytta, Peter Nagel, Fatemeh Ghorbani, Amir Ghiami, Santanu Pakhira, Mai Ye, Bjoern Wehinger, Federico Abbruciati, Gaston Garbarino, Matthieu Le Tacon, Stefan Schuppler, Amir-Abbas Haghighirad, Michael Merz
The high-temperature phase of Ta$ _\mathrm{2}$ NiSe$ _\mathrm{5}$ , a near-zero-gap semiconductor ($ E_G$ = 0), is a promising candidate for an excitonic insulator. Given the dome-like evolution expected for an excitonic insulator around $ E_G$ , we investigated Ta$ _\mathrm{2}$ NiSe$ _\mathrm{5}$ , the more semi-metallic Ta$ _\mathrm{2}$ (Ni,Co)Se$ _\mathrm{5}$ , and semiconducting Ta$ _\mathrm{2}$ NiS$ _\mathrm{5}$ using high-resolution single-crystal x-ray diffraction and near-edge x-ray absorption fine structure (NEXAFS). Our findings reveal a second-order structural phase transition from orthorhombic (space group: $ Cmcm$ ) to monoclinic (space group: $ C2/c$ ) in Ta$ _\mathrm{2}$ NiSe$ _\mathrm{5}$ and Ta$ _\mathrm{2}$ (Ni,Co)Se$ _\mathrm{5}$ , but no transition in Ta$ _\mathrm{2}$ NiS$ _\mathrm{5}$ down to 2 K. This transition breaks two mirror symmetries, enabling and enhancing the hybridization of Ta, Ni, and Se atoms, shortening bond lengths, and strengthening orbital interactions. NEXAFS data confirm stronger hybridization, significant changes in excitonic binding energies, and a key alteration in orbital character, suggesting an excitonic insulating state in Ta$ _\mathrm{2}$ NiSe$ _\mathrm{5}$ and emphasizing the crucial electronic role of orbitals in the formation of the excitonic insulator state.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
10 pages, 6 figures, accepted for publication in Scientific Reports
A heat-resilient hole spin qubit in silicon
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-22 20:00 EDT
V. Champain, G. Boschetto, H. Niebojewski, B. Bertrand, L. Mauro, M. Bassi, V. Schmitt, X. Jehl, S. Zihlmann, R. Maurand, Y.-M. Niquet, C. B. Winkelmann, S. De Franceschi, B. Martinez, B. Brun
Recent advances in scaling up spin-based quantum processors have revealed unanticipated issues related to thermal effects. Microwave pulses required to manipulate and read the qubits are found to overheat the spins environment, which unexpectedly induces Larmor frequency shifts, reducing thereby gate fidelities. In this study, we shine light on these elusive thermal effects, by experimentally characterizing the temperature dependence of the Larmor frequency for a single hole spin in silicon. Our results unambiguously reveal an electrical origin underlying the thermal susceptibility, stemming from the spin-orbit-induced electric susceptibility. We perform an accurate modeling of the spin electrostatic environment and gyromagnetic properties, allowing us to pinpoint electric dipoles as responsible for these frequency shifts, that unfreeze as the temperature increases. Surprisingly, we find that the thermal susceptibility can be tuned with the magnetic field angle and can even cancel out, unveiling a sweet spot where the hole spin is rendered immune to thermal effects. These findings bear important implications for optimizing spin-based quantum processors fidelity.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
Novel Quantum Spin Liquid states in the $S = {\frac{1}{2}}$ three-dimensional compound Y${3}$Cu${2}$Sb${3}$O${14}$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-22 20:00 EDT
Saikat Nandi, Rounak Das, Sagar Mahapatra, Jörg Sichelschmidt, M. Hemmida, H.-A. Krug von Nidda, Marlis Schuller, N. Büttgen, John Wilkinson, M. P. Saravanan, Indra Dasgupta, A.V. Mahajan
The three-dimensional $ S = 1/2$ system Y$ _{3}$ Cu$ _{2}$ Sb$ _{3}$ O$ _{14}$ consists of two inequivalent Cu$ ^{2+}$ ions, each forming edge shared triangular lattices. Our magnetic susceptibility $ \chi(T)=M/H$ , specific heat $ C_p(T)$ , $ ^{89}$ Y nuclear magnetic resonance (NMR), muon spin relaxation ($ \mu$ SR), and electron spin resonance (ESR) measurements on this system confirm the absence of any long-range magnetic ordering and the persistence of spin dynamics down to 0.077 K. From $ ^{89}$ Y NMR we find evidence of a transition at about 120 K which we suggest to arise from a fraction of the spins condensing into a singlet (a valence bond solid VBS or a quantum spin liquid QSL) state. A plateau in the muon relaxation rate is observed between 60 K and 10 K (signifying the VBS/QSL state from a fraction of the spins) followed by an increase and another plateau below about 1 K (presumably signifying the VBS/QSL state from all the spins). Our density functional theory calculations find a dominant antiferromagnetic interaction along the body diagonal with inequivalent Cu(1) and Cu(2) ions alternately occupying the corners of the cube. All other near neighbour interactions between the Cu ions are also found to be antiferromagnetic and are thought to drive the frustration.
Strongly Correlated Electrons (cond-mat.str-el)
Unsupervised and probabilistic learning with Contrastive Local Learning Networks: The Restricted Kirchhoff Machine
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-09-22 20:00 EDT
Marcelo Guzman, Simone Ciarella, Andrea J. Liu
Autonomous physical learning systems modify their internal parameters and solve computational tasks without relying on external computation. Compared to traditional computers, they enjoy distributed and energy-efficient learning due to their physical dynamics. In this paper, we introduce a self-learning resistor network, the Restricted Kirchhoff Machine, capable of solving unsupervised learning tasks akin to the Restricted Boltzmann Machine algorithm. The circuit relies on existing technology based on Contrastive Local Learning Networks, in which two identical networks compare different physical states to implement a contrastive local learning rule. We simulate the training of the machine on the binarized MNIST dataset, providing a proof of concept of its learning capabilities. Finally, we compare the scaling behavior of the time, power, and energy consumed per operation as more nodes are included in the machine to their Restricted Boltzmann Machine counterpart operated on CPU and GPU platforms.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Computational Physics (physics.comp-ph)
Formation of Cavity-Polaritons via High-Order Van Hove Singularities
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-09-22 20:00 EDT
Igor Gianardi, Michele Pini, Francesco Piazza
We consider polaritons formed by hybridizing particle-hole excitations of an insulating phase with a cavity photon at sub-gap frequencies, where absorption is suppressed. The strength of the hybridization is driven by the Van Hove singularity in the JDOS at the band gap: the stronger the singularity, the more a photon is hybridized with the interband transitions. In order to increase the singularity and thus the polariton hybridization without absorption, we propose to engineer a non-parabolic momentum dispersion of the bands around the gap in order to implement a high-order Van Hove singularity (HOVHS) in the JDOS. Ultracold atoms in tunable optical lattices are an ideal platform to engineer two-dimensional gapped phases with non-trivial band dispersions at the gap. Moreover, the intrinsic non-interacting nature of polarized fermionic atoms prevents the emergence of sub-gap excitations, which are common in solid-state systems and could otherwise spoil the absence of absorption below the gap. Our findings identify band-engineering at the gap edge as a promising route for polariton control with applications in quantum-nonlinear optics.
Quantum Gases (cond-mat.quant-gas), Optics (physics.optics), Quantum Physics (quant-ph)
14 pages, 9 figures
Mechanistic Insights into Complete Methane Oxidation on Single-Atom Pd Supported by SSZ-13 Zeolite: A First-Principles Study
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-22 20:00 EDT
Anuroopa Behatha, Shalini Tomar, Hojin Jeong, Joon Hwan Choi, Seung-Cheol Lee, Satadeep Bhattacharjee
Complete catalytic oxidation of methane is an effective strategy for greenhouse gas mitigation and clean energy conversion; yet, ensuring both high catalytic activity and stability with palladium-based catalysts remains a challenge. In the present work, we employed a theoretical investigation of methane oxidation over single-atom Pd supported on SSZ-13 zeolite using density functional theory calculations, combined with climbing-image nudged elastic band calculations to determine activation barriers. A systematic assessment of various Al distributions and Pd placements was carried out to identify the most stable configurations for Pd incorporation within the zeolite this http URL, two mechanistic routes for methane activation were evaluated: (i) direct dehydrogenation under dry conditions, and (ii) O$ _2$ -assisted oxidative dehydrogenation. Our results demonstrate that the direct (dry) pathway is energetically demanding and overall endothermic, whereas the O$ _2$ assisted route facilitates the exothermic energy profile, particularly in the C-H bond cleavage. The formation of stable hydroxyl and CO/CO$ _2$ intermediates were also studied. The results emphasize the role of oxygen-rich environments in enabling the complete methane oxidation with improved thermodynamic feasibility. Moreover, we propose an alternate low-energy pathway based on O-assisted and multi-site mechanisms that reduce the overall reaction enthalpy. These insights provide the design principles for highly active and moisture-resistant Pd-zeolite catalysts for sustainable methane utilization.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
An Equivariant Graph Network for Interpretable Nanoporous Materials Design
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-22 20:00 EDT
Zhenhao Zhou, Salman Bin Kashif, Dawei Feng, Jin-Hu Dou, Kaihang Shi, Tao Deng, Zhenpeng Yao
Nanoporous materials hold promise for diverse sustainable applications, yet their vast chemical space poses challenges for efficient design. Machine learning offers a compelling pathway to accelerate the exploration, but existing models lack either interpretability or fidelity for elucidating the correlation between crystal geometry and property. Here, we report a three-dimensional periodic space sampling method that decomposes large nanoporous structures into local geometrical sites for combined property prediction and site-wise contribution quantification. Trained with a constructed database and retrieved datasets, our model achieves state-of-the-art accuracy and data efficiency for property prediction on gas storage, separation, and electrical conduction. Meanwhile, this approach enables the interpretation of the prediction and allows for accurate identification of significant local sites for targeted properties. Through identifying transferable high-performance sites across diverse nanoporous frameworks, our model paves the way for interpretable, symmetry-aware nanoporous materials design, which is extensible to other materials, like molecular crystals and beyond.
Materials Science (cond-mat.mtrl-sci), Artificial Intelligence (cs.AI)
Bacteria collective motion is scale-free
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-22 20:00 EDT
Benjamin Perez-Estay, Vincent Martinez, Carine Douarche, Jana Schwarz-Linek, Jochen Arlt, Pierre-Henri Delville, Gail McConnell, Wilson C. K. Poon, Anke Lindner, Eric Clement
Suspensions of swimming bacteria interact hydrodynamically over long ranges, organizing themselves into collective states that drive large-scale chaotic flows, often referred to as “bacterial turbulence”. Despite extensive experimental and theoretical work, it remains unclear whether an intrinsic length scale underlies the observed patterns. To shed light on the mechanism driving active turbulence, we investigate the emergence of large-scale flows in E. coli suspensions confined within cylindrical chambers, systematically varying confinement height over more than two orders of magnitude. We first demonstrate that the critical density for the onset of collective motion scales inversely with this confinement height without saturation, even for the smallest densities observed. Near the onset, both the observed length and time scales increase sharply, with the length scale bounded only by the vertical confinement. Importantly, both scales exhibit clear power-law dependence on the confinement height, demonstrating the absence of an intrinsic length scale in bacterial collective motion. This holds up to scales nearly 10,000 times the size of a single bacterium, as evidenced by transient coherent vortices spanning the full chamber width near the onset. Our experimental results demonstrating that bacterial turbulence is scale-free provide important constraints for theories aiming to capture the dynamics of wet active matter.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
Giant shot noise in superconductor/ferromagnet junctions with orbital-symmetry-controlled spin-orbit coupling
New Submission | Superconductivity (cond-mat.supr-con) | 2025-09-22 20:00 EDT
César González-Ruano, Chenghao Shen, Pablo Tuero, Coriolan Tiusan, Yuan Lu, Jong E. Han, Igor Žutić, Farkhad G. Aliev
By measuring the shot noise, a consequence of charge quantization, in superconductor/insulator/ferromagnet (V/MgO/Fe) junctions, we discover a giant increase, orders of magnitude larger than expected. The origin of this giant noise is a peculiar realization of a superconducting proximity effect, where a simple superconductor influences its neighbors. Our measurements reveal largely unexplored implications of orbital-symmetry-controlled proximity effects. The importance of orbital symmetries and the accompanying spin-orbit coupling is manifested by an unexpected emergence of another superconducting region strikingly different from the parent superconductor. Unlike vanadium’s common spin-singlet superconductivity, the broken inversion symmetry in V/MgO/Fe junctions and the resulting interfacial spin-orbit coupling leads to the formation of spin-triplet superconductivity across the ferromagnetic iron. Here we show that the enhanced shot noise, known from Josephson junctions with two superconductors, is measured even in a single superconductor, this discovery motivates revisiting how the spin-orbit coupling and superconducting proximity effects can transform many materials.
Superconductivity (cond-mat.supr-con)
Accepted for publication
A stochastic heat engine driven using a nonlinear protocol
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-22 20:00 EDT
Amrutayani Panda, Biswajit Das, Shuvojit Paul, Arnab Saha, Ayan Banerjee
A colloidal particle confined in a time-dependent optical trap can function as a microscopic heat engine, with optimization strategies playing a crucial role in enhancing its performance. In this study, we numerically investigate a Stirling heat engine operating in both passive and active environments using a protocol inspired by the Engineered Swift Equilibration (ESE) method. This approach differs from the standard process and focuses on enhancing engine efficiency, particularly at short time scales. We analyze various fluctuating parameters throughout the cycle to validate the robustness of the engine, and demonstrate a significant enhancement in performance compared to conventional Stirling engines. Most crucially, we observe that the nonlinear protocol can even transform a heat-pump-like operation into a genuine heat engine under strong activity, thereby surpassing bounds imposed on efficiency by high-temperature and quasi-static conditions. Finally, the proposed protocol is designed with experimental feasibility in mind, making it a promising framework for the practical realization of efficient microscopic heat engines.
Statistical Mechanics (cond-mat.stat-mech)
8 pages, 8 figures, comments are welcome
Attractive Multidimensional Solitons in Trapping Potentials
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-09-22 20:00 EDT
Fatkhulla Abdullaev, Mario Salerno
This paper reviews theoretical advances on the formation and stabilization of multidimensional solitons in nonlinear Schrödinger systems with attractive interactions, focusing on atomic Bose-Einstein condensates and nonlinear optics. While 1D solitons are generally stable, their 2D and 3D counterparts are prone to collapse. Several mechanisms have been proposed to mitigate this, including optical lattices, modulation of the nonlinearity via Feshbach resonance management, and Rabi coupling between hyperfine states. Other approaches involve competing nonlinearities and quantum corrections, such as Lee-Huang-Yang effects. Emphasis is placed on conditions enabling long-lived or fully stable solitons. Despite experimental feasibility, achieving robust stabilization remains challenging due to the intricate interplay of nonlinearities and external controls. The paper surveys collapse dynamics, stabilization strategies, and soliton existence based on key theoretical contributions.
Quantum Gases (cond-mat.quant-gas)
27 pages, 10 figures; This preprint is the version prior to its acceptance as a chapter of the book “Short and Long Range Quantum Atomic Platforms – Theoretical and Experimental Developments” (provisional title) edited by P.G. Kevrekidis , C.L. Hung, and S. I. Mistakidis, Springer Tracts in Modern Physics Series, Springer Nature Switzerland AG, Gewerbestrasse 11, 6330 Cham, Switzerland
Non-Fermi liquid behaviour of CDW instabilities in fractionally-filled moiré flatbands
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-22 20:00 EDT
Spin- and valley-polarized fractionally-filled moiré flatbands are known to host emergent Fermi-liquid phases, when analyzed with the help of a dual description in terms of holes. The dominant Coulomb interactions in an almost flatband endow the fermions with a nontrivial dispersion, when the system is described in terms of the hole operators (rather than the particle operators). In particular, for one-fourth filling, the Fermi surface takes a quasi-triangular shape, which brings about the possibility of charge-density-wave (CDW) ordering in the ground state, characterized by the nesting vectors ($ \mathbf{Q}_n $ ). The $ \mathbf{Q}_n$ ‘s connect antipodal points of the Fermi surface (designated as hot-spots) and are found to belong to the space of reciprocal vectors of the underlying honeycomb structure. The resulting CDW order can be described in terms of instabilities caused by bosonic fields with momenta centred at $ \lbrace \mathbf{Q}_n \rbrace $ , coupling with the fermions residing in the vicinity of a pair of antipodal hot-spots. When there is a transition from a Fermi liquid to a CDW state, the bosons become massless (or critical), effectuating a non-Fermi liquid behaviour. We set out to identify such non-Fermi liquid phases after constructing a minimal effective action.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), High Energy Physics - Theory (hep-th)
13 pages, 4 figures. arXiv admin note: text overlap with arXiv:2403.02322
Phase Behavior and Ion Transport in Lithium-Niobium-Tantalum Oxide Alloys
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-22 20:00 EDT
Hengning Chen, Zeyu Deng, Gopalakrishnan Sai Gautam, Yan Li, Pieremanuele Canepa
Lithium niobate-tantalate mixtures have garnered considerable interest for their ability to merge the desirable properties of both end members, enabling diverse high-value applications, such as high-performance faradaic capacitors, non-linear optics, and protective coatings in rechargeable batteries. While numerous studies on the application of $ \mathrm{LiNb_xTa_{1-x}O_3}$ exist, the phase behavior and properties of $ \mathrm{Li_3Nb_xTa_{1-x}O_4}$ remain largely unexplored. In this work, we employ a multiscale approach that encompasses first-principles phonon calculations, cluster expansion, and Monte Carlo simulations to derive the temperature-composition phase diagram for $ \mathrm{Li_3Nb_xTa_{1-x}O_4}$ . Our findings reveal the critical role of vibrational entropy in accurately predicting phase stability, which promotes the solubility of Nb in $ \mathrm{Li_3TaO_4}$ while suppressing the miscibility of Ta in $ \mathrm{Li_3NbO_4}$ . Additionally, we demonstrate that Nb/Ta mixing offers a promising avenue for tailoring the Li-ion conductivities of $ \mathrm{Li_3Nb_xTa_{1-x}O_4}$ . On the technical side, we demonstrated the importance of including vibrational entropy effects explicitly in Monte Carlo simulations dealing with multicomponent systems, beyond simple binary mixtures. On the application side, this study provides fundamental insights into the phase behavior and Li-ion transport properties of $ \mathrm{Li_3Nb_xTa_{1-x}O_4}$ , paving the way for its potential applications in energy storage and other fields.
Materials Science (cond-mat.mtrl-sci), Statistical Mechanics (cond-mat.stat-mech)
Phonon polariton Hall effect
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-22 20:00 EDT
Omer Yaniv, Dominik M. Juraschek
The phonon Hall effect conventionally describes the generation of a transverse heat current in an applied magnetic field. In this work, we extend the effect to hybrid light-matter excitations and demonstrate theoretically that phonon polaritons, formed by coupling optical phonons with terahertz radiation, support transverse energy flow when coherently driven in an applied magnetic field. Using the example of PbTe, which exhibits strongly coupled phonon polaritons, we show that the magnetic field splits the phonon-polariton branches into left and right-handed circular polarization, obtaining unequal group velocities. We derive the energy current operators for propagating phonon polaritons and show how their mixed phononic-photonic nature enables controllable transverse phonon-polariton transport in the terahertz regime. Our results demonstrate bending of light through a phonon polariton Hall effect, which provides a route towards terahertz polaritonic devices.
Materials Science (cond-mat.mtrl-sci)
Nonreciprocal plasmons in one-dimensional carbon nanostructures
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-22 20:00 EDT
Álvaro Rodríguez Echarri, F. Javier García de Abajo, Joel D. Cox
The directional control of light in miniaturized plasmonic waveguides holds appealing possibilities for emerging nanophotonic technologies, but is hindered by the intrinsic reciprocal optical response of conventional plasmonic materials. While the ability of graphene to sustain large electrical currents shows promise for nonreciprocal plasmonics, studies have been limited to extended samples characterized by linear electrical dispersion. Here, we theoretically explore quantum finite-size and nonlocal effects in the nonreciprocal response of mesoscale plasmonic waveguides comprised of drift-biased graphene nanoribbons (GNRs) and carbon nanotubes (CNTs). Using atomistic simulation methods based on tight-binding electronic states and self-consistent mean-field optical response, we reveal that a moderate electrical bias can significantly break reciprocity for propagation of guided plasmon modes in GNRs and CNTs exhibiting electronic band gaps. The excitation by a nearby point dipole emitter and subsequent propagation of guided plasmon modes can thus be actively controlled by the applied current, which can further be leveraged to mediate nonlocal interactions of multiple emitters. Our results establish graphene nanostructures as a promising atomically thin platform for nonreciprocal nanophotonics.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Optics (physics.optics)
16 pages, 12 figures
Electronic bounds in magnetic crystals
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-22 20:00 EDT
We present a systematic study of bound relations between different electronic properties of magnetic crystals: electron density, effective mass, orbital magnetization, localization length, Chern invariant, and electric susceptibility. All relations are satisfied for a group of low-lying bands, while some remain valid for upper bands. New results include a lower bound on the electric susceptibility of Chern insulators, and an upper bound on the sum-rule part of the orbital magnetization. In addition, bounds involving the Chern invariant are generalized from two dimensions (Chern number) to three (Chern vector). Bound relations are established for metals as well as insulators, and are illustrated for model systems. The manner in which they approach saturation in a model Chern insulator with tunable flat bands is analyzed in terms of the optical absorption spectrum.
Materials Science (cond-mat.mtrl-sci)
Classical and Quantum theory of magnonic and magnetoelastic nonlinear dynamics in continuum geometries
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-22 20:00 EDT
Marco Brühlmann, Yunyoung Hwang, Jorge Puebla, Carlos Gonzalez-Ballestero
We provide a theory of spin and acoustic wave coupled nonlinear dynamics in continuum systems. Combining the Landau-Lifshitz-Gilbert equations with the magnetoelastic Hamiltonian, we derive classical equations of motion for the magnetization and acoustic wave amplitudes, that include magnonic nonlinearity – both three- and four-magnon processes – as well as linear and nonlinear magnetoelastic interactions. We focus on two-dimensional magnetic films sustaining surface acoustic waves, a geometry where our model successfully reproduces our recent experimental observation of phonon-to-magnon down-conversion under acoustic drive. We provide analytical expressions for all the rates in our equations, which make them particularly suitable for quantization. We then quantize our model, deriving Heisenberg-Langevin equations of motion for magnon and phonon operators, and show how to compute quantum expectation values in the mean field approximation. Our work paves the way toward acoustic control of magnons in the quantum regime.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
16+5 pages, 9 figures
Exploring confinement transitions in $\mathbb{Z}_2$ lattice gauge theories with dipolar atoms beyond one dimension
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-09-22 20:00 EDT
Matjaž Kebrič, Lin Su, Alexander Douglas, Michal Szurek, Ognjen Marković, Ulrich Schollwöck, Annabelle Bohrdt, Markus Greiner, Fabian Grusdt
Confinement of particles into bound states is a phenomenon spanning from high-energy to condensed matter physics, which can be studied in the framework of lattice gauge theories (LGTs). Achieving a comprehensive understanding of confinement continues to pose a major challenge, in particular at finite matter density and in the presence of strong quantum fluctuations. State-of-the-art quantum simulators constitute a promising platform to address this problem. Here we study confinement in coupled chains of $ \mathbb{Z}_2$ LGTs coupled to matter fields, that can be mapped to a mixed-dimensional (mixD) XXZ model. We perform large-scale numerical matrix-product state calculations to obtain the phase diagram of this model, in which we uncover striped phases formed by the $ \mathbb{Z}_2$ charges that can be melted at finite temperature or by increasing the tunneling rate. To explore this setting experimentally, we use our quantum simulator constituted by erbium atoms with dipolar interactions in a quantum gas microscope, and observe the predicted melting of a stripe phase by increasing the particle tunneling rate. Our explorative experimental studies of thermal deconfinement of $ \mathbb{Z}_2$ charges motivate our further theoretical study of the mixD $ \mathbb{Z}_2$ LGT, in which we predict a confined meson gas at finite temperature and low magnetization where thermal fluctuations destroy stripes but enable spontaneous commensurate spin order. Overall, we demonstrate that our platform can be used to study confinement in $ \mathbb{Z}_2$ LGTs coupled to matter fields, including long-range interactions and beyond one dimension, paving the way for future research of confinement in the quantum many-body regime.
Quantum Gases (cond-mat.quant-gas), Strongly Correlated Electrons (cond-mat.str-el), High Energy Physics - Lattice (hep-lat), Atomic Physics (physics.atom-ph), Quantum Physics (quant-ph)
16 + 9 pages, 10 + 6 figures