CMP Journal 2025-09-20
Statistics
Physical Review Letters: 4
Physical Review X: 1
arXiv: 66
Physical Review Letters
Genuine Quantum Effects in Dicke-Type Models at Large Atom Numbers
Article | Atomic, Molecular, and Optical Physics | 2025-09-19 06:00 EDT
Kai Müller and Walter T. Strunz
We investigate the occurrence of genuine quantum effects and beyond mean-field physics in the balanced and unbalanced open Dicke models with a large yet finite number of atoms . Such driven and dissipative quantum many-body systems have recently been realized in experiments involving ultracold gase…
Phys. Rev. Lett. 135, 123602 (2025)
Atomic, Molecular, and Optical Physics
Evidence for Multiband Gapless Superconductivity in the Topological Superconductor Candidate $4\mathrm{Hb}\text{-}{\text{TaS}}_{2}$
Article | Condensed Matter and Materials | 2025-09-19 06:00 EDT
Hanru Wang, Yihan Jiao, Fanyu Meng, Xu Zhang, Dongzhe Dai, Chengpeng Tu, Chengcheng Zhao, Lu Xin, Sicheng Huang, Hechang Lei, and Shiyan Li
Thermal conductance measurements on the layered transition metal dichalcogenide 4-TaS reveal multiband gapless superconductivity.
Phys. Rev. Lett. 135, 126002 (2025)
Condensed Matter and Materials
Twist-on-Twist Moiré Elastic Metasurfaces
Article | Condensed Matter and Materials | 2025-09-19 06:00 EDT
Menghan Li, Kuan He, Zhiwen Ren, Li-Qun Chen, Hao-Wen Dong, Chenglin Han, Tianzhi Yang, and Cheng-Wei Qiu
The concepts of twistronics and magic angle have been widely applied beyond electrons, powering up new advancements in optics, acoustics, and heat transport. However, achieving a unidirectional or all-direction "magic angle" remains an established yet unresolved challenge in twisted bilayer metasurf…
Phys. Rev. Lett. 135, 126301 (2025)
Condensed Matter and Materials
Shape Switching and Tunable Oscillations of Adaptive Droplets
Article | Polymers, Chemical Physics, Soft Matter, and Biological Physics | 2025-09-19 06:00 EDT
Tim Dullweber, Roman Belousov, Camilla Autorino, Nicoletta I. Petridou, and Anna Erzberger
Living materials adapt their shape to signals from the environment, yet the impact of shape changes on signal processing and associated feedback dynamics remains unclear. We find that droplets with signal-responsive interfacial tensions exhibit shape bistability, excitable dynamics, and oscillations…
Phys. Rev. Lett. 135, 128404 (2025)
Polymers, Chemical Physics, Soft Matter, and Biological Physics
Physical Review X
Complexity of Gottesman-Kitaev-Preskill States
Article | | 2025-09-19 06:00 EDT
Lukas Brenner, Libor Caha, Xavier Coiteux-Roy, and Robert Koenig
A proposed protocol efficiently prepares high-quality Gottesman-Kitaev-Preskill (GKP) quantum states with rigorous accuracy guarantees. Since GKP states are central to quantum error correction, this paves the way for more robust quantum computing.
Phys. Rev. X 15, 031073 (2025)
arXiv
Mixed Quantum-Classical Approaches to Spin Current and Polarization Dynamics in Chiral Molecular Junctions
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-19 20:00 EDT
Yu Wang, Ruihao Bi, Wei Liu, Jiayue Han, Wenjie Dou
Chiral molecular junctions offer a promising platform for realizing chiral-induced spin selectivity (CISS), where spin filtering occurs without external magnetic fields. Here, we investigate spin transport in such junctions by combining quantum master equation (QME) methods for purely electronic dynamics with surface hopping (SH) and mean-field Ehrenfest (MF) approaches to incorporate electron-phonon coupling. Our results show that transient spin polarization arises but ultimately decays to zero at long times. We find that bias voltage, molecular length, and spin-orbit coupling (SOC) strongly influence the spin current dynamics: higher bias enhances spin current but reduces polarization, while longer molecules and stronger SOC amplify transient polarization. Including electron-phonon coupling modifies current-voltage characteristics, enhancing spin currents at intermediate bias but suppressing them at high bias, while leaving the polarization dynamics largely unchanged. These findings highlight the interplay between electronic and vibrational effects in CISS and provide guidance for designing molecular spintronic devices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Chemical Physics (physics.chem-ph), Quantum Physics (quant-ph)
30 pages, 10 figures
Theory of Sondheimer magneto-oscillations beyond semiclassical limit
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-19 20:00 EDT
Alexander Nikolaenko, Pavel A. Nosov
In conducting films subjected to an out-of-plane magnetic field, electron motion along the field direction gives rise to conductance oscillations periodic in field intensity - a phenomenon known as Sondheimer oscillations. Traditionally, these oscillations were understood within the semiclassical framework of kinetic theory. However, their behavior in the quantum regime (i.e. at strong fields and weak disorder) remains unclear, particularly due to potential interference with quantum Shubnikov-de Haas magneto-oscillations. In this work, we develop a comprehensive theory of quantum magnetoconductivity oscillations in metallic films of finite thickness, fully capturing the interplay between the Sondheimer and Shubnikov-de Haas effects beyond the semiclassical limit. By treating surface scattering, in-plane Landau quantization, and dimensional confinement along the magnetic field direction on equal footing, we reveal an intricate hierarchy of oscillation patterns and characterize how their amplitudes and frequencies depend on various physical parameters. Our results pave the way for systematic characterization of thin metallic films with boundary-dominated transport properties.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
26 pages, 12 Figures
Stress Response of Jammed Solids: Prestress and Screening
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-19 20:00 EDT
Surajit Chakraborty, Jishnu N. Nampoothiri, Subhro Bhattacharjee, Bulbul Chakraborty, Kabir Ramola
Unlike classical elasticity, where stresses arise from deformations relative to a stress-free reference configuration, rigidity in amorphous systems is maintained by disordered force networks that generate internal prestress. Previously, we introduced a ‘’stress-only’’ formulation, where mechanical equilibrium resembles Gauss’s law in a rank-2 tensor electrostatics with vector charges, and demonstrated that the mechanical response of jammed solids is described by the dielectric response of this gauge-theoretic formulation. Here, we extend this framework by incorporating scale-dependent screening that captures both dielectric and Debye-type behaviour. This introduces a characteristic length scale in stress correlations as well as in the response to external forces. Through numerical simulations of soft-sphere packings, we show that this length scale is set by the particle size, thus providing a natural ultraviolet cutoff while preserving long-wavelength emergent elasticity. We show that this lengthscale remains finite for all pressures, with no evidence for an emergent Debye-like screening near the frictionless unjamming transition. We demonstrate that although individual realisations show strong fluctuations, disorder averaging at fixed macroscopic conditions yields a robust dielectric-like response that persists up to unjamming. Finally, we also provide a physical interpretation of the gauge field within the electrostatic mapping: relative grain displacements in response to localised external perturbations correspond to difference in the gauge field, linking the field-theoretic description to particle-level mechanics.
Soft Condensed Matter (cond-mat.soft), Disordered Systems and Neural Networks (cond-mat.dis-nn), Statistical Mechanics (cond-mat.stat-mech)
Defects in Wigner crystals: fracton-elasticity duality and vacancy proliferation
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-19 20:00 EDT
We develop a low-energy field theory for electrically charged crystals. Using the tools of fracton-elasticity duality, generalized to accommodate the magnetic 1-form symmetry of electromagnetism, we show how the elastic and electromagnetic degrees of freedom couple to the different crystal defects and to one another. The resulting field theory is then used to calculate vacancy-vacancy interaction energy, and to study the consequences of vacancy proliferation. We find that the longitudinal mode, which in a perfect crystal has a finite gap due to plasma oscillations, becomes gapless in the presence of vacancies. Our framework lays a foundation for a study of defect interactions, their collective dynamics, and consequences of defect-mediated melting in charged crystals.
Strongly Correlated Electrons (cond-mat.str-el), High Energy Physics - Theory (hep-th)
10+5 pages, 4 figures
Thermodynamic constraints and pseudotransition behavior in a one-dimensional water-like system
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-19 20:00 EDT
F. F. Braz, S. M. de Souza, M. L. Lyra, Onofre Rojas
We investigate a one-dimensional water-like lattice model with Van der Waals and hydrogen-bond interactions, allowing for particle number fluctuations through a chemical potential. The model, defined on a chain with periodic boundary conditions, exhibits three ground-state phases: gas, bonded liquid, and dense liquid, separated by sharp phase boundaries in the chemical potential and temperature plane. Using the transfer matrix method, we derive exact analytical results within the grand-canonical ensemble and examine the finite-temperature behavior. The system exhibits clear pseudotransition features, including sharp but analytic changes in entropy, density, and internal energy, along with finite peaks in specific heat and correlation length. To assess the role of thermodynamic constraints, we consider the behavior under fixed density through a Legendre transformation. This constrained analysis reveals smoother anomalies, such as entropy kinks and finite jumps in specific heat, contrasting with the sharper grand-canonical signatures. These results underscore the ensemble dependence of pseudotransitions and show how statistical constraints modulate critical-like behavior. We also verify that the residual entropy continuity criterion holds in the grand-canonical ensemble but is violated when the system is constrained. Our findings illustrate how even a simple one-dimensional model can mimic water-like thermodynamic anomalies.
Statistical Mechanics (cond-mat.stat-mech)
101 pages, 9 figures
How Microplastics cross the Buoyancy Barrier: A multi-scale Study
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-19 20:00 EDT
Thomas Witzmann, Anja F. R. M. Ramsperger, Hao Liu, Yifan Lu, Holger Schmalz, Lucas Kurzweg, Tom C. D. Börner, Kathrin Harre, Andreas Greiner, Christian Laforsch, Holger Kress, Christina Bogner, Stephan Gekle, Andreas Fery, Günter K. Auernhammer
Microplastics (MPs), though less dense than water, are frequently recovered from sediments in aqueous environments, indicating they can cross the buoyancy barrier. We quantify eco-corona mediated MP-sediment attraction and MP transport from the nanoscale to the macroscale, linking all scales to a coherent mechanism explaining how MP overcome buoyancy and settle in sediments through interaction with suspended sediment.
Colloidal probe atomic force microscopy (CP-AFM) detected attractive forces (0.15 - 17 mN/m) enabling heteroaggregation. Microscale tests confirmed aggregation and on larger scales sediment retention more than doubled with an eco-corona. Simulations showed that environmental shear force ($ 4 \cdot 10^{-4} mN/m$ ) cannot disrupt aggregates. In sedimentation columns, biofilm-covered MPs settled twice as often as plain MPs in bentonite suspensions. MP retention increased by 32 %. These results demonstrate that eco-corona/biofilm-mediated heteroaggregation is a robust pathway for MP sinking, accumulation, and retention in sediment beds. By identifying physical interaction thresholds and aggregation stability, we provide mechanistic insight into MP fate, highlight probable accumulation hotspots, and offer an evidence base for improved risk assessment and environmental modelling.
Soft Condensed Matter (cond-mat.soft)
General approach for partitioning and phase separation in macromolecular coexisting phases
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-19 20:00 EDT
Vikki Anand Varma, Alberto Scacchi
Partitioning of (bio)materials in polymeric mixtures is a key phenomenon both in cellular environments, as well as in industrial applications. In cells, several macromolecules are suspended within different biomolecular phases. On the other hand, the coexistence of polymeric aqueous phases has been exploited for the extraction and purification of (bio)materials suspended in water. Despite its relevance, key physical and chemical properties controlling the phase behavior of these complex systems are still lacking. Here, we have developed a classical density functional theory approach for describing the phase coexistence and partitioning of an arbitrary number of polymers and suspended materials. As a case example, we focus on a binary mixture of phase separating polymers in which a third material is dispersed. We explore the effect of size ratios and affinities between the different materials and address their distribution and coexisting densities, and find optimal conditions for partitioning.
Soft Condensed Matter (cond-mat.soft)
Quenched properties of the Spectral Form Factor
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-19 20:00 EDT
Dimitrios Charamis, Manas Kulkarni, Jorge Kurchan, Laura Foini
The Spectral Form Factor (SFF) is defined as the modulus squared of the partition function in complex temperature for hermitian matrices and a suitable generalisation has been given in the non hermitian case. In this work we compute the properties of the quenched SFF for hermitian and non hermitian random matrices. Despite the fact that the (annealed) SFF is not self-averaging the quenched SFF is self-averaging but these two averages coincide up to subleading constants (at least for high enough temperatures). The fluctuations of $ \log \mathrm{SFF}$ are deep and one encounters thin spikes when moving close to a zero of the partition function. We study the partition function at late times by considering a suitable change of variable which turns out to be compatible with a Gumbel distribution. We note that the exponential tails of this distribution can be obtained by the deep spikes in the $ \log \mathrm{SFF}$ , namely the zeros of the partition function. We compare with the results obtained in isolated many-body systems and we show that same results hold at late times also for non-hermitian Hamiltonains and non-hermitian random matrices.
Statistical Mechanics (cond-mat.stat-mech), High Energy Physics - Theory (hep-th), Quantum Physics (quant-ph)
Deep Gaussian Process-based Cost-Aware Batch Bayesian Optimization for Complex Materials Design Campaigns
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-19 20:00 EDT
Sk Md Ahnaf Akif Alvi, Brent Vela, Vahid Attari, Jan Janssen, Danny Perez, Douglas Allaire, Raymundo Arroyave
The accelerating pace and expanding scope of materials discovery demand optimization frameworks that efficiently navigate vast, nonlinear design spaces while judiciously allocating limited evaluation resources. We present a cost-aware, batch Bayesian optimization scheme powered by deep Gaussian process (DGP) surrogates and a heterotopic querying strategy. Our DGP surrogate, formed by stacking GP layers, models complex hierarchical relationships among high-dimensional compositional features and captures correlations across multiple target properties, propagating uncertainty through successive layers. We integrate evaluation cost into an upper-confidence-bound acquisition extension, which, together with heterotopic querying, proposes small batches of candidates in parallel, balancing exploration of under-characterized regions with exploitation of high-mean, low-variance predictions across correlated properties. Applied to refractory high-entropy alloys for high-temperature applications, our framework converges to optimal formulations in fewer iterations with cost-aware queries than conventional GP-based BO, highlighting the value of deep, uncertainty-aware, cost-sensitive strategies in materials campaigns.
Materials Science (cond-mat.mtrl-sci)
Gravity-driven flux of particles through apertures
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-19 20:00 EDT
Ram Sudhir Sharma, Alexandre Leonelli, Kevin Zhao, Eckart Meiburg, Alban Sauret
The gravity-driven discharge of granular material through an aperture is a fundamental problem in granular physics and is classically described by empirical laws with different fitting parameters. In this Letter, we disentangle the mass flux into distinct velocity and packing contributions by combining three-dimensional experiments and simulations. We define a dimensionless flux ratio that captures confinement-driven deviations from a free-fall limit, which is recovered when the aperture is large compared to the grain size. For spherical cohesionless grains, the deviations from the free-fall limit are captured by a single exponential correction factor over a characteristic length scale of $ \sim$ 10-15 grain diameters. This is shown to be the scale over which the packing structure is modified due to the boundary. We propose a new kinematic framework that explains the universality of granular discharge beyond empirical descriptions.
Soft Condensed Matter (cond-mat.soft)
Main (4 pages, 4 figures) and Supplementary (9 pages, 7 figures)
Dynamics of an outlier in the Gaussian Unitary Ensemble
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-19 20:00 EDT
John Mateus, Gabriel Téllez, Frédéric van Wijland
We endow the elements of a random matrix drawn from the Gaussian Unitary Ensemble with a Dyson Brownian motion dynamics. We initialize the dynamics of the eigenvalues with all of them lumped at the origin, but one outlier. We solve the dynamics exactly which gives us a window on the dynamical scaling behavior at and around the Baik-Ben Arous-Péché transition. Amusingly, while the statics is well-known and accessible via the Hikami-Brézin integrals, our approach for the dynamics is explicitly based on the use of orthogonal polynomials.
Statistical Mechanics (cond-mat.stat-mech)
On the equivalence and optimality of transformations of diffusive systems
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-19 20:00 EDT
Davide Gabrielli, Giovanni Jona-Lasinio
In this paper we introduce, inspired by Clausius and developing the ideas of \cite{pre}, the concept of equivalence of transformations in non equilibrium theory of diffusive systems within the framework of macroscopic fluctuation theory. Besides providing a new proof of a formula derived in \cite{mft,qc}, which is the basis of the equivalence, we show that equivalent quasistatic transformations can be distinguished in finite terms, by the renormalized work introduced in \cite{45,46,mft,qc}. This allows us to tackle the problem of determining the optimal quasistatic transformation among the equivalent ones.
Statistical Mechanics (cond-mat.stat-mech)
14 pages, no figures; to appear on J. Stat. Phys
Density Dependence of the Phases of the $ν= 1$ Integer Quantum Hall Plateau in Low Disorder Electron Gases
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-19 20:00 EDT
Haoyun Huang, Waseem Hussain, S.A. Myers, L.N. Pfeiffer, K.W. West, G.A. Csáthy
Recent magnetotransport measurements in low-disorder electron systems confined to GaAs/AlGaAs samples revealed that the $ \nu = 1$ integer quantum Hall plateau is broken into three distinct regions. These three regions were associated with two phases with different types of bulk localization: the Anderson insulator is due to random quasiparticle localization, and the integer quantum Hall Wigner solid is due to pinning of a stiff quasiparticle lattice. We highlight universal properties of the $ \nu = 1$ plateau: the structure of the stability diagram, the non-monotonic dependence of the activation energy on the filling factor, and the alignment of features of the activation energy with features of the stability regions of the different phases are found to be similar in three samples spanning a wide range of electron densities. We also discuss quantitative differences between the samples, such as the dependence of the onset temperature and the activation energy of the integer quantum Hall Wigner solid on the electron density. Our findings provide insights into the localization behavior along the $ \nu = 1$ integer quantum Hall plateau in the low disorder regime.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
Physica Status Solidi RRL 19, 2400376 (2025)
The Varieties of Schelling Model Experience
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-19 20:00 EDT
Marlyn Boke, Timothy Sorochkin, Jesse Anttila-Hughes, Alan O. Jamison
The Schelling model is a prototype for agent-based modeling in social systems. A comprehensive analysis of Schelling model rule variants is achieved by classification of the space of macroscopic outcomes via phase diagrams. Among 54 rule variants, only 3 phase diagram classes are found, characterized by the number of phase transitions. This classification scheme is found to be robust to the use of sociological and percolation-inspired measures of segregation. The statistical and dynamic drivers of these transitions are elucidated by analyzing the roles of vision, movement criteria, vacancies, the initial state, and rivalry. Schelling’s original step function dictating satisfaction is found to be pathological at high thresholds, producing coordination failures as satisfactory sites become increasingly rare. This comprehensive classification gives new insight into the drivers of transitions in the Schelling model and creates a basis for studying more complex Schelling-like models.
Statistical Mechanics (cond-mat.stat-mech), Computational Physics (physics.comp-ph)
Mixed order phase transition in a locally constrained exclusion process
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-19 20:00 EDT
We investigate a novel variant of the exclusion process in which particles perform asymmetric nearest-neighbor jumps across a bond ((k, k+1)) only if the preceding site ((k-1)) is unoccupied. This next-nearest-neighbor constraint significantly enriches the system’s dynamics, giving rise to long-range correlations and a mixed-order transition controlled by the asymmetry parameter. We focus on the critical case of half filling, where the system splits into two ergodic components, each associated with an invariant reversible measure. The combinatorial structure of this equilibrium distribution is intimately connected to the (q)-Catalan numbers, enabling us to derive rigorously the asymptotic behavior of key thermodynamic quantities in the strongly asymmetric regime and to conjecture their behavior in the weakly asymmetric limit. Even though the system is one-dimensional and has short-range interactions, an equilibrium phase transition occurs between a clustered phase – characterized by slow dynamics, long-range correlations with thermodynamic additivity, and spontaneous breaking of translational symmetry – and a fluid phase where the correlations are short-range and which is thermodynamically additive. This equilibrium phase transition features characteristics of a first-order transition, such as a discontinuous order parameter as well as characteristics of a second-order transition, namely a divergent susceptibility at the transition point. We also briefly discuss density higher than one half where ergodicity is broken.
Statistical Mechanics (cond-mat.stat-mech), Mathematical Physics (math-ph)
Coupled Interfacial Phenomena Suppress Propulsion in Catalytic Janus Colloids
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-19 20:00 EDT
Muhammad Haroon, Christopher Wirth
Platinum-coated polystyrene Janus particles exhibit a combination of stochastic and deterministic motion in hydrogen peroxide solutions, making them promising candidates for applications in micro-scale cargo transport, drug delivery, and environmental remediation. The dynamics of Janus particles very near a boundary are dictated by conservative and non-conservative interactions that depend on particle, substrate, and solution properties. This study investigated the influence of orientational quenching by measuring the effect of changes in cap thickness and hydrogen peroxide concentration on particle velocity and maximum displacement. Janus particles with cap thicknesses of 3 nm, 7 nm, 10 nm, 20 nm, and 35 nm were analyzed in 1 wt./vol.% and 3 wt./vol.% hydrogen peroxide solutions near the bottom and top boundaries of the fluid cell. Results indicated that particles with lower cap thicknesses exhibit higher velocities, with faster particles in 3 wt./vol.% peroxide as compared to 1 wt./vol.% peroxide. Furthermore, results suggest a combined influence of activity and gravitational effects influenced whether particles moved along the top boundary i.e. ceiling or bottom boundary i.e. flooring. Heavier cap particles in lower peroxide concentration solution show less ceiling than lighter cap particles in higher peroxide concentration. We also find a global reduction in velocity for when a single surface of the two is plasma cleaned surface. These findings highlight the important interplay between cap weight, hydrodynamic interactions, and propulsion force in determining the dynamics of Janus particles.
Soft Condensed Matter (cond-mat.soft)
Dipole condensates in synthetic rank-2 electric fields
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-09-19 20:00 EDT
Jiali Zhang, Wenhui Xu, Qi Zhou, Shaoliang Zhang
Dipole condensates, formed from particle-hole pairs, represent a unique class of charge-neutral quantum fluids that evade conventional vector gauge fields, making their electrodynamic responses difficult to probe in natural materials. Here, we propose a tunable platform using strongly interacting two-component ultracold atoms to realize dipole condensates and probe their coupling to rank-2 electric fields. By applying spin-dependent forces and treating spin as a synthetic dimension, we engineer a synthetic rank-2 electric field that induces measurable electrodynamic responses. We identify the atomic analog of perfect Coulomb drag: increasing intercomponent interactions leads to equal and opposite displacements of the centers of mass of the two spin components. Furthermore, a rank-2 electric field imprints a phase twist in the dipole condensate and generates a supercurrent of dipoles that obeys the dipolar Josephson relation – a smoking gun for dipole condensation. Our results establish a powerful platform for exploring dipolar superfluidity under tensor gauge fields.
Quantum Gases (cond-mat.quant-gas)
7 pages, 5 figures
Data coarse graining can improve model performance
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-19 20:00 EDT
Alex Nguyen, David J. Schwab, Vudtiwat Ngampruetikorn
Lossy data transformations by definition lose information. Yet, in modern machine learning, methods like data pruning and lossy data augmentation can help improve generalization performance. We study this paradox using a solvable model of high-dimensional, ridge-regularized linear regression under ‘data coarse graining.’ Inspired by the renormalization group in statistical physics, we analyze coarse-graining schemes that systematically discard features based on their relevance to the learning task. Our results reveal a nonmonotonic dependence of the prediction risk on the degree of coarse graining. A ‘high-pass’ scheme–which filters out less relevant, lower-signal features–can help models generalize better. By contrast, a ‘low-pass’ scheme that integrates out more relevant, higher-signal features is purely detrimental. Crucially, using optimal regularization, we demonstrate that this nonmonotonicity is a distinct effect of data coarse graining and not an artifact of double descent. Our framework offers a clear, analytical explanation for why careful data augmentation works: it strips away less relevant degrees of freedom and isolates more predictive signals. Our results highlight a complex, nonmonotonic risk landscape shaped by the structure of the data, and illustrate how ideas from statistical physics provide a principled lens for understanding modern machine learning phenomena.
Statistical Mechanics (cond-mat.stat-mech), Disordered Systems and Neural Networks (cond-mat.dis-nn), Machine Learning (cs.LG), Neurons and Cognition (q-bio.NC), Machine Learning (stat.ML)
7 pages, 4 figures
Laughlin charge pumping from interplay of chiral Dirac and chiral Majorana modes
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-19 20:00 EDT
Zhan Cao, Yang Feng, Zhi-Hai Liu, Ke He
Laughlin charge pumping has provided critical insights into the topological classification of individual materials, but remains largely unexplored in topological junctions. We explore Laughlin charge pumping in junctions composed of a chiral topological superconductor sandwiched between two quantum anomalous Hall insulators, driven by an adiabatically varying magnetic flux. Here, charge pumping can be mediated merely by chiral Dirac modes or by the interplay of chiral Dirac and chiral Majorana modes (CMMs). In the former case, a variation of one magnetic flux quantum induces the pumping of a unit charge, as the chiral Dirac mode accumulates the full flux-induced phase. In contrast, in the latter case, pumping a unit charge requires a variation of fractional magnetic flux quanta, determined by the device geometry and the parity of the number of enclosed superconducting vortices. This unique feature results from the charge-neutral and zero-momentum nature of zero-energy CMMs. Our work offers an experimentally viable pathway toward detecting CMMs and could also inspire further research into Laughlin charge or spin pumping in diverse topological junctions, which are now within experimental reach.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Main text: 7 pages, 4 figures, and 2 tables; Supplemental material: 5 pages, 1 figure
Physical Review Research 7, L032060 (2025)
Data-driven discovery of governing equation for sheared granular materials in steady and transient states
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-19 20:00 EDT
Xu Han, Lu Jing, Chung-Yee Kwok, Gengchao Yang, Yuri Dumaresq Sobral
Granular material has significant implications for industrial and geophysical processes. A long-lasting challenge, however, is seeking a unified rheology for its solid- and liquid-like behaviors under quasi-static, inertial, and even unsteady shear conditions. Here, we present a data-driven framework to discover the hidden governing equation of sheared granular materials. The framework, PINNSR-DA, addresses noisy discrete particle data via physics-informed neural networks with sparse regression (PINNSR) and ensures dimensional consistency via machine learning-based dimensional analysis (DA). Applying PINNSR-DA to our discrete element method simulations of oscillatory shear flow, a general differential equation is found to govern the effective friction across steady and transient states. The equation consists of three interpretable terms, accounting respectively for linear response, nonlinear response and energy dissipation of the granular system, and the coefficients depends primarily on a dimensionless relaxation time, which is shorter for stiffer particles and thicker flow layers. This work pioneers a pathway for discovering physically interpretable governing laws in granular systems and can be readily extended to more complex scenarios involving jamming, segregation, and fluid-particle interactions.
Soft Condensed Matter (cond-mat.soft)
24 pages, 6 figures, 1 table
Controlled Polarization Switch in a Polariton Josephson Junction
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-19 20:00 EDT
Valeria A. Maslova, Nina S. Voronova
The interaction between a particle’s spin and momentum – known as spin-orbit (SO) coupling – is the cornerstone of modern spintronics. In Bose-Einsten condensates of ultracold atoms, SO coupling can be implemented and precisely controlled experimentally; photonic systems, on the other hand, possess an intrinsic SO interaction due to the longitudinal-transverse splitting of the photon modes. In this work, we focus on such spinor, SO-coupled exciton-polariton condensates on a ring, where the strength of the synthetic magnetic field is controlled by the geometrical dimensions of the structure. Inspired by recent experiments, we investigate the dynamics of a weakly-nonlinear four-mode bosonic Josephson junction within this geometry. We discover a narrow parameter range in which the interplay of the tunneling dynamics with polariton-specific SO coupling leads to a new regime, with dynamical switching of the fluid’s circular polarization degree to the opposite, along the entire ring or on just one of its halves. Our results demonstrate polariton condensates in ring configurations as excellent candidates for all-optical controllable spin-switch applications, with prospects for scalability and observing non-trivial polarization patterns.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Gases (cond-mat.quant-gas)
6 pages of main text, 4 figures, and 10 pages Supplementary Material, 3 figures
S1-MatAgent: A planner driven multi-agent system for material discovery
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-19 20:00 EDT
Xinrui Wang, Chengbo Li, Boxuan Zhang, Jiahui Shi, Nian Ran, Linjing Li, Jianjun Liu, Dajun Zeng
The discovery of high-performance materials is crucial for technological advancement. Inverse design using multi-agent systems (MAS) shows great potential for new material discovery. However, current MAS for materials research rely on predefined configurations and tools, limiting their adaptability and scalability. To address these limitations, we developed a planner driven multi-agent system (S1-MatAgent) which adopts a Planner-Executor architecture. Planner automatically decomposes complex materials design tasks, dynamically configures various tools to generate dedicated Executor agents for each subtask, significantly reducing reliance on manual workflow construction and specialized configuration. Applied to high-entropy alloy catalysts for hydrogen evolution reactions in alkaline conditions, S1-MatAgent completed full-cycle closed-loop design from literature analysis and composition recommendation to performance optimization and experimental validation. To tackle the deviations between designed materials and target, as well as high experimental verification costs, S1-MatAgent employs a novel composition optimization algorithm based on gradients of machine learning interatomic potential, achieving 27.7 % improvement in material performance. S1-MatAgent designed 13 high-performance catalysts from 20 million candidates, with Ni4Co4Cu1Mo3Ru4 exhibiting an overpotential of 18.6 mV at 10 mA cm-2 and maintaining 97.5 % activity after 500 hours at 500 mA cm-2. The universal MAS framework offers a universal and scalable solution for material discovery, significantly improving design efficiency and adaptability.
Materials Science (cond-mat.mtrl-sci)
Density Functional Theory Analysis of Na3AgO: Assessing its Viability as a Sustainable Material for Solar Energy Applications
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-19 20:00 EDT
Vipan Kumar, Shyam Lal Gupta, Sumit Kumar, Ashwani Kumar, Pooja Rana, Diwaker
This study mainly emphasis the fascinating features of inverse perovskites Na3AgO using density functional theory (DFT). Inverse perovskite (IP) Na3AgO structural features have been examined, and the space group and cubic structure of Pm-3m (221) have been confirmed. The experimental formulation and thermal stability of IP have been confirmed by the formation energy. Phonon dispersion curves were used to assess dynamic stability. The dynamic stability of the examined IP and the bonding strength against cubic structure deformation are confirmed by the lack of negative frequencies. The energy gap or the characteristics of semiconducting behaviour have been predicted by the electronic properties of Na3AgO with a band gap of 1.273 eV. In order to confirmthe viability of solar cells, the light-dependent properties have also been identified. Born stability criteria are also used to verify the mechanical stability, and additional elastic characteristics are identified in order to forecast the anisotropy, ductility, strength, and hardness. These anti-perovskites, which possess intriguing characteristics, have the potential to be effective materials for photovoltaic applications, as indicated by the analysed findings.
Materials Science (cond-mat.mtrl-sci)
Violation of Spin Paramagnetic limit in Bi/Ni Bilayer
New Submission | Superconductivity (cond-mat.supr-con) | 2025-09-19 20:00 EDT
Gabriel Sant’Ana, Leonardo Pessoa da Silva, Pedro Schio, David Möckli, Jan Aarts, Kaveh Lahabi, Milton A. Tumelero
We report a violation of the spin-paramagnetic limit in the in-plane upper critical field ($ B_{C2}^{\parallel}$ ) in Bi(10 nm)/Ni(1 nm) bilayers grown by molecular beam epitaxy (MBE). Superconductivity emerges at the interface through the formation of an ultrathin NiBi$ 3$ layer, which hosts a remarkably robust superconducting state under in-plane magnetic fields. To account for the $ B{C2}^{\parallel}$ enhancement, we evaluate two-dimensional (2D) superconductivity models incorporating spin-orbit scattering and Rashba-type spin-orbit coupling. However, none of these mechanisms fully capture the observed behavior. We discuss the potential role of unconventional pairing, possibly linked to spin fluctuations. Our findings suggest that, in the 2D limit, NiBi$ _3$ may support a superconducting state beyond the standard spin-singlet framework.
Superconductivity (cond-mat.supr-con)
Emergent momentum-space topological pseudospin defects in non-Hermitian systems
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-19 20:00 EDT
Yow-Ming Robin Hu, Elena A. Ostrovskaya, Alexander Yakimenko, Eliezer Estrecho
Topological defects are central to modern physics, from spintronics to photonics, due to their robustness and potential application in information processing. In this work, we discuss topological point defects that spontaneously emerge at the imaginary Fermi arcs (degeneracy lines) in momentum space of two-dimensional systems described by non-Hermitian effective Hamiltonians. In particular, we consider a generic non-Hermitian Dirac model and a phenomenological model describing hybrid light-matter quasiparticles - exciton polaritons hosted in an optical microcavity. In both cases, the eigenenergies of the system have both real and imaginary parts and form two distinct bands corresponding to two (pseudo-)spin states. We describe the trajectories of the point defects characterized by integer-valued topological winding (vorticity) analytically and show that the defects with opposite vorticity annihilate with each other in the fully gapped phases, but are protected from annihilation by the non-Hermitian spectral degeneracies (exceptional and hybrid points) in the gapless phases. We also suggest that the signatures of these defects can be experimentally measured in an exciton-polariton system.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Optics (physics.optics)
12 pages, 9 figures
Rotational dynamics of bound pairs of bacteria-induced membrane tubes
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-19 20:00 EDT
Makarand Diwe, P B Sunil Kumar, Pramod Pullarkat
We present experiments demonstrating tube formation in giant unilamellar vesicles that are suspended in a bath of swimming E. coli bacteria. We chose the lipids such that the bacteria have no adhereing interaction with the membrane. The tubes are generated by the pushing force exerted by the bacteria on the membrane of the vesicles. Once generated, the bacteria are confined within the tubes, resulting in long-lived tubes that protrude into the vesicle. We show that such tubes interact to form stable bound pairs that orbit each other. We speculate that the tubes are maintained by the persistent pushing force generated by the bacterium, and the rotating pairs are stabilized by a combination of curvature mediated interaction and vorticity generated in the membrane by the rotation of the flagella.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
12 pages, 6 figures
Thermal rectification in jointless Pb solid wire
New Submission | Superconductivity (cond-mat.supr-con) | 2025-09-19 20:00 EDT
Masayuki Mashiko, Poonam Rani, Yuto Watanabe, Yoshikazu Mizuguchi
Thermal rectification is observed in jointless Pb wires at temperatures near the superconducting transition of Pb under magnetic fields. Using different magnetic-field (H) response of temperature dependence of thermal conductivity (\k{appa}-T) under H parallel to J and H perpendicular to J where J is heat flow, we fabricated a jointless thermal diode. Thermal rectification is observed with the thermal rectification ratio (TRR) of 1.5 and the difference in \k{appa} of 330 W m-1 K-1 at T = 5.11 K under H = 400 Oe for a Pb wire with a 50%-bent (H perpendicular to J) and 50%-straight (H parallel to J) structure. The peak temperature of TRR can be tuned by the strength of applied magnetic field. By changing bent ratio to 40%-bent, a higher TRR exceeding 2 was observed. The Pb-jointless thermal diode will be a useful material for thermal management at cryogenic temperatures.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci)
14 pages, 5 figures, 1 table, SI
Zero-energy resonances in ultracold hydrogen sticking to liquid helium films of finite thickness
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-09-19 20:00 EDT
R. Karahanyan, A. Voronin, V. Nesvizhevsky, A. Semakin, S. Vasiliev
We investigated quantum states of ultracold hydrogen atoms in a combined potential comprising the H-He film interaction in the presence of a substrate and the Earth gravitational field. We show that the shift and width of the gravitational quantum states are determined by the complex scattering length for the H-He film-substrate potential. We demonstrate that for specific helium film thicknesses above a substrate, zero-energy resonances occur if the combined potential supports a bound state exactly at the threshold. This effect leads to a complete restructuring of the bound states spectrum. The dynamics of gravitational levels as a function of the van der Waals interaction depth controlled by the helium film thickness is analyzed. It reveals the critical thicknesses at about 6.1 and 1.8 nm, at which resonances appear in the case of the conductive substrate. With imaginary integral operators, we incorporate non-perturbatively the inelastic effects originating from the ripplon coupling. The inelastic effects show dramatic changes in the sticking-coefficient behavior near the critical points. The enhanced sticking coefficients provide a probe for studying critical phenomena and measuring atom-surface interaction parameters with unprecedented sensitivity.
Quantum Gases (cond-mat.quant-gas), Quantum Physics (quant-ph)
Three-Dimensional Domain-Wall Membranes
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-19 20:00 EDT
Jacob Mankenberg, Artem Abanov
Three-dimensional magnetic textures, such as Hopfions, torons, and skyrmion tubes, possess rich geometric and topological structure, but their detailed energetics, deformation modes, and collective behavior are yet to be fully understood. In this work, we develop an effective geometric theory for general three-dimensional textures by representing them as embedded two-dimensional orientable domain-wall membranes. Using a local ansatz for the magnetization in terms of membrane coordinates, we integrate out the internal domain-wall profile to obtain a reduced two-dimensional energy functional. This functional captures the coupling between curvature, topology, and the interplay of micromagnetic energies, and is expressed in terms of a small set of soft-mode fields: the local wall thickness and in-plane magnetization angle. Additionally, we construct a local formula for the Hopf index which sheds light on the coupling between geometry and topology for nontrivial textures. We analyze the general properties of the theory and demonstrate its utility through the example of a flat membrane hosting a vortex as well as a toroidal Hopfion, obtaining analytic solutions for the wall thickness profile, associated energetics, and a confirmation of the Hopf index formula. The framework naturally extends to more complex geometries and can accommodate additional interactions such as Dzyaloshinskii-Moriya, Zeeman, and other anisotropies, making it a versatile tool for exploring the interplay between geometry, topology, and micromagnetics in three-dimensional spin systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
14 pages, 6 figures, submitted to PRB
Intrinsic characteristic radius drives phonon anomalies in Janus transition metal dichalcogenide nanotubes
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-19 20:00 EDT
Transition metal dichalcogenides and their derivatives offer a versatile platform for exploring novel structural and functional properties in low-dimensional materials. In particular, Janus monolayers possess an intrinsic out-of-plane asymmetry that induces a built-in bending radius, which can strongly influence their physical behavior. In this work, we investigate the tubular structures formed by rolling Janus monolayers into the Janus nanotube with an extrinsic radius. Using a combination of atomistic simulations and continuum mechanics, we identify that the total energy of the Janus nanotube is minimized when the tube radius equals to the intrinsic bending radius of the Janus monolayer. An analytical expression for this characteristic radius is derived, providing a theoretical basis for understanding the stability of Janus nanotubes. Furthermore, we find that the optical phonon modes in these Janus nanotubes exhibit an anomalous dependence on the tube radius; i.e., their frequencies reach a maximum value near the characteristic radius, in contrast to the monotonic increase of optical phonon frequencies with radius in conventional nanotubes. The phonon anomaly is due to the soft phonon mode effect induced by the deviation from the most stable tubular configuration with the characteristic radius. These results uncover a unique coupling between intrinsic and extrinsic curvature in Janus systems and open new pathways for tuning vibrational and other properties in curved low-dimensional materials.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
22 pages, 11 figures
Chiral twist-bend liquid crystals
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-19 20:00 EDT
Recently published preprint ( A. Ashkinazi, this http URL, this http URL, this http URL, J.P.K. Doye, ‘’Chirality transfer in lyotropic twist-bend nematics’’, arXiv:2508.03544v1 (2025)) has reawakened also interest to various mechanisms of chirality transfer from microscopic (molecular) level into the macroscopic chirality of the structure. In this communication we present a simple theoretical analysis how the transfer occurs for the Landau model of phase transition between cholesteric and chiral twist-bend liquid crystals. We found that the sign of the chiral heliconical spiral is always opposite to that of the cholesteric. Physics behind this relation is based on the orthogonality of the cholesteric director and vector order parameter of the heliconical phase.
Soft Condensed Matter (cond-mat.soft)
3 pages
A General Model for Static Contact Angles
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-19 20:00 EDT
The problem of contact angle and hysteresis determination has direct implications for engineering applications of wetting, colloid and surface science. Significant technical challenges can arise under real-world operating conditions, because the static contact angle is strongly influenced by contamination at the liquid-solid and liquid-vapor interfaces, chemical aging over long times, and environmental variables such as relative humidity and temperature. Analytical models that account for these real-world effects are therefore highly desirable to guide the rational design of robust applications. This work proposes a unified and simple-to-use model that expands Young’s local thermodynamic approach to consider surfaces with topographic features of general geometry and varying degrees of liquid infiltration. The unified model recovers classical wetting limits (Wenzel, Cassie-Baxter, and hemiwicking), accounts for observable intermediate states (e.g., impregnating Cassie), and identifies a new limiting state with potential realizability: a Cassie state accompanied by a precursor film, termed the Inverse Wenzel state.
Soft Condensed Matter (cond-mat.soft), Fluid Dynamics (physics.flu-dyn)
14 pages, 4 figures
Multiple many-body localization transitions in a driven non-Hermitian quasiperiodic chain
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-09-19 20:00 EDT
Sanchayan Banerjee, Ayan Banerjee, Tapan Mishra, Flore K. Kunst
We investigate the fate of a many-body localized phase in a non-Hermitian quasiperiodic model of hardcore bosons subjected to periodic driving. While in general, the many-body localized system is known to thermalize with increasing driving period due to Floquet heating, in this case, we demonstrate that the initially localized system first delocalizes and then localizes again, resulting in a re-entrant many-body localization (MBL) transition as a function of the driving period. Strikingly, further increase in the driving period results in a series of localization-delocalization transitions leaving behind traces of extended regimes (islands) in between MBL phases. Furthermore, non-Hermiticity renders the extended islands boundary-sensitive, resulting in a Floquet many-body skin effect under open boundaries. We present numerical evidence from spectral and dynamic studies, confirming these findings. Our study opens new pathways for understanding the interplay between non-Hermiticity and quasiperiodicity in driven systems.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
Cost Reduction in Spin-dependent Stochastic GW Calculations
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-19 20:00 EDT
We extend the stochastic GW (sGW) formalism to fully spin-polarized systems, encompassing both collinear and non-collinear spin configurations. For non-collinear systems-where Kohn-Sham states are complex two-component spinors-we develop a complex-valued stochastic basis that preserves the real-valued external stochastic charge applied at time zero. This basis enables an unbiased evaluation of the random-phase approximation (RPA) screened interaction for spinors. Through error analysis and tests on real materials, we show that the performance of collinear sGW retains the same time complexity as the spin-unpolarized sGW . The non-collinear sGW incurs a computational cost two to three times higher than the spin-unpolarized version, while preserving linear scaling with low multiplicity. By unifying collinear and non-collinear treatments within a single scalable framework, our work paves the way for routine many-body predictions in large scale magnetic and spin-orbit-coupled material systems.
Materials Science (cond-mat.mtrl-sci)
Computational uncertainties in lattice thermal conductivity prediction of crystalline solids
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-19 20:00 EDT
Yagyank Srivastava, Amey G. Gokhale, Ankit Jain
We report computational uncertainties in Boltzmann Transport Equation (BTE)-based lattice thermal conductivity prediction of 50 diverse semiconductors from the use of different BTE solvers (ShengBTE, Phono3Py, and in-house code) and interatomic forces. The interatomic forces are obtained either using the density functional theory (DFT) as implemented in packages Quantum Espresso and VASP employing commonly used exchange correlation functionals (PBE, LDA, PBEsol, and rSCAN) or using the pre-trained foundational machine learning forcefields trained on two different material datasets.
We find that the considered BTE solvers introduce minimal uncertainties and, using the same interatomic force constants, all solvers result in an excellent agreement with each other, with a mean absolute percentage error (MAPE) of only 1%. While this error increases to around 10% with the use of different DFT packages, the error is still small and can be reduced further with the use of stringent planewave energy cutoffs. On the other hand, the differences in thermal conductivity due to the use of different exchange correlation functionals are large, with a MAPE of more than 20%. The currently available pre-trained foundational ML models predict the right trend for thermal conductivity, but the associated errors are high, limiting their applications for coarse screening of materials.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Computational Physics (physics.comp-ph)
Resonantly enhanced photoemission from topological surface states in MnBi$6$Te${10}$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-19 20:00 EDT
Paulina Majchrzak, Alfred J. H. Jones, Klara Volckaert, Xing-Chen Pan, Philip Hofmann, Yong P. Chen, Jill A. Miwa, Søren Ulstrup
The dispersion of topological surface bands in MnBi$ _2$ Te$ _4$ -based magnetic topological insulator heterostructures is strongly affected by band hybridization and is spatially inhomogeneous due to varying surface layer terminations on microscopic length scales. Here, we apply micro-focused angle-resolved photoemission spectroscopy with tunable photon energy from 18 to 30 eV to distinguish bulk valence and conduction bands from surface bands on the three surface terminations of MnBi$ _6$ Te$ _10$ . We observe a strong enhancement of photoemission intensity from the topological surface bands at the Bi O4 absorption edge, which is exploited to visualize a gapless Dirac cone on the MnBi$ _2$ Te$ _4$ -terminated surface and varying degrees of hybridization effects in the surface bands on the two distinct Bi$ _2$ Te$ _3$ -terminated surfaces.
Materials Science (cond-mat.mtrl-sci)
7 pages, 4 figures
J. Phys. Condens. Matter 37 385501 (2025)
Detection of ferroic octupole ordering in $d$-wave altermagnetic rutile-type compounds
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-19 20:00 EDT
Masaichiro Mizumaki, Norimasa Sasabe, Takayuki Uozumi, Rikuto Oiwa, Hiroaki Kusunose
We propose that X-ray absorption and emission magnetic circular dichroism (XAS-MCD and XES-MCD) are promising measurements to directly detect ferroic higher-rank multipoles as candidate order parameters in altermagnets. Using the sum rules for XES-MCD and connecting them to multipole language, we demonstrate that the expectation value of the magnetic octupole moment is finite in the $ d$ -wave altermagnetic candidate rutile-type compounds TF$ _2$ (T=transition metal). We also perform spectral calculations of XAS-MCD and XES-MCD based on an effective model with a full multiplet approach. While the intensity of the XAS-MCD spectra vanishes, the XES-MCD spectra exhibit finite intensity, whose spectrum becomes opposite by inverting the Nèel vector. These results clearly indicate ferroic magnetic octupole order in these compounds.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
Thickness Dependence and Fundamental Limitations for Ion Permeation in Nanoscale Films
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-19 20:00 EDT
Jay Prakash Singh, Konstantin I. Morozov, Viatcheslav Freger
Nanoscale films play a central role in biology and osmotic separations. Their water/salt selectivity is often regarded as intrinsic property, favoring thinner membranes for faster permeation. Here we highlight and quantify a fundamental limitation arising from the dependence of ion self-energy on film thickness, governed by its ratio to Bjerrum length. The resulting relation factors out this dependence from intrinsic ion permeability, which agrees well with available data and enables evaluation of dielectric properties of ultrathin films, advancing understanding of ion transport in membranes.
Soft Condensed Matter (cond-mat.soft), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Biological Physics (physics.bio-ph)
High-Throughput Quantification of Altermagnetic Band Splitting
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-19 20:00 EDT
Ali Sufyan, Brahim Marfoua, J. Andreas Larsson, Erik van Loon, Rickard Armiento
Altermagnetism represents a recently established class of collinear magnetism that combines zero net magnetization with momentum-dependent spin polarization, enabled by symmetry constraints rather than spin-orbit coupling. This distinctive behavior gives rise to sizable spin splitting even in materials composed of light, earth-abundant elements, offering promising prospects for next-generation spintronics applications. Despite growing theoretical and experimental interest, the discovery of altermagnetic materials remains limited due to the complexity of magnetic symmetry and the inefficiency of conventional approaches. Here, we present a comprehensive high-throughput screening of the entire MAGNDATA database, integrating symmetry analysis with spin-polarized density functional theory (DFT) calculations to identify and characterize altermagnetic candidates. Our workflow uncovers 173 materials exhibiting significant spin splitting ($ \geq 50$ meV within $ \pm 3$ eV of the Fermi level), spanning both metallic and semiconducting systems. Crucially, our momentum-resolved analysis reveals that the spin splitting varies strongly across the Brillouin zone, and that the maximal splitting tends to occur away from the high-symmetry paths, a result that directly informs and guides future photoemission experiments. By expanding the catalog of known altermagnets and elucidating the symmetry-protected origins of spin splitting, this work lays a robust foundation for future experimental and theoretical advances in spintronics and quantum materials discovery.
Materials Science (cond-mat.mtrl-sci)
Thermoelectric properties of defective scandium nitride nanostructures
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-19 20:00 EDT
Luigi Cigarini, Urszula Danuta Wdowik, Dominik Legut
Transition-metal nitrides (TMNs) are currently being studied for potential applications in energy conversion. In this work, we used the Landauer approach to relate the various effects contributing to the thermoelectric efficiency of scandium nitride (ScN) to their microscopic origins. We model the impact of electronic and structural modifications induced by oxygen impurities and spatial vacancies on electronic transport in ScN nanostructures. Taking advantage of the results of our calculations, we propose a theoretical interpretation of recent experimental results revealing a strong dependence of the thermoelectric properties of ScN thin films on procedural variations during fabrication. The thermoelectric properties of ScN are decisively influenced by structural and electronic factors arising from defects or impurities. Our findings highlight the potential of this theoretical approach in studying thermoelectricity and uncovering future strategies to improve thermoelectric efficiency.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Applied Physics (physics.app-ph), Chemical Physics (physics.chem-ph), Computational Physics (physics.comp-ph)
12 pages, 13 figures
Hydrodynamic Attraction and Hindered Diffusion Govern First-passage Times of Swimming Microorganisms
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-19 20:00 EDT
Yanis Baouche, Magali Le Goff, Thomas Franosch, Christina Kurzthaler
The motion of microorganisms in their natural habitat is strongly influenced by their propulsion mechanisms, geometrical constraints, and random fluctuations. Here, we study numerically the first-passage-time (FPT) statistics of microswimmers, modeled as force-dipoles, to reach a no-slip wall. Our results demonstrate that hindered diffusion near the wall can increase the median FPT by orders of magnitude compared to “dry” agents, while the intricate interplay of active motion and hydrodynamic attraction speeds up the arrival at large Péclet numbers (measuring the importance of self-propulsion relative to diffusion). Strikingly, it leads to a non-monotonic behavior as a function of the dipole strength, where pushers reach the wall significantly faster than pullers. The latter become slower at an intermediate dipole strength and are more sensitive to their initial orientation, displaying a highly anisotropic behavior.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
Spin-photon coupling using circular double quantum dots
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-19 20:00 EDT
Ferdinand Omlor, Florinda Viñas Boström, Martin Leijnse
We propose and analyze a microwave spin-photon interface based on a circular double quantum dot, inspired by recent experimental observations of anisotropic g-factors and ring states in InAs nanowires. We develop an effective theoretical model capturing the interplay of spin-orbit coupling and the magnetic flux through the ring and show how ring states form at crossings of odd and even geometrical parity orbital states. Similar to bonding and antibonding states of conventional double quantum dots, the ring eigenstates can be changed into single dot states by detuning the dots, which enables a high degree of control over the system’s properties. Applying a tilted magnetic field induces spin-charge hybridization which enables spin-photon coupling. For low disorder, the photons couple states of simultaneously (almost) opposite spin and angular momentum. With increasing disorder, the spin-photon coupling becomes analogous to the flopping mode mechanism of conventional double quantum dots where the spin is hybridized with the bonding and antibonding orbital states without angular momentum. We show that the system exhibits a second-order charge-noise sweet spot at a specific magnetic field angle, which lowers the system’s sensitivity to dephasing while retaining a substantial spin-photon coupling strength. Moreover, the photon coupling mechanism can be switched off either electrically, by detuning to the single-dot regime, or magnetically, by rotating the field to disable the spin-charge hybridization.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
13 pages, 6 figures, 1 table
DNA mold-based fabrication of continuous silver nanostructures
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-19 20:00 EDT
Christoph Hadlich, Borja Rodriguez-Barea, Darius Pohl, Bernd Rellinghaus, Artur Erbe, Ralf Seidel
Bottom-up fabrication of inorganic nanostructures is emerging as an alternative to classical top-down approaches, offering precise nanometer-scale control at relatively low cost and effort. In particular, DNA nanostructures provide versatile scaffolds for directly templating the growth of metal structures. Previously, a DNA mold-based method for metal nanostructure synthesis has been established that supports a modular structure design and a high control over the structure formation. So far, this method was limited to the growth of gold and palladium nanostructures. Here, we report the successful adaptation of the DNA mold-based fabrication method to produce continuous silver nanowires. By optimizing reagent concentrations and applying gentle thermal annealing, we obtain continuous wire structures of several hundred nanometer length, overcoming limitations in anisotropic growth. Despite the strong interaction of silver ions with DNA, we can control the growth without increasing the complexity of our approach. Our structures are not oxidized yet they did not exhibit conductivity. This work demonstrates the versatility of DNA-templated metallization and opens new opportunities for constructing self-assembled hybrid nanostructures with controlled shape and composition.
Materials Science (cond-mat.mtrl-sci)
Statistics makes a difference: Machine learning adsorption dynamics of functionalized cyclooctine on Si(001) at DFT accuracy
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-19 20:00 EDT
Hendrik Weiske, Rhyan Barrett, Ralf Tonner-Zech, Patrick Melix, Julia Westermayr
The interpretation of experiments on reactive semiconductor surfaces requires statistically significant sampling of molecular dynamics, but conventional ab initio methods are limited due to prohibitive computational costs. Machine-learning interatomic potentials provide a promising solution, bridging the gap between the chemical accuracy of short ab initio molecular dynamics (AIMD) and the extensive sampling required to simulate experiment. Using ethinyl-functionalized cyclooctyne adsorption on Si(001) as a model system, we demonstrate that conventional AIMD undersamples the configurational space, resulting in discrepancies with scanning tunnelling microscopy and X-ray photoelectron spectroscopy data. To resolve these inconsistencies, we employ pre-trained equivariant message-passing neural networks, fine-tuned on only a few thousand AIMD snapshots, and integrate them into a “molecular-gun” workflow. This approach generates 10,000 independent trajectories more than 1,000 times faster than AIMD. These simulations recover rare intermediates, clarify the competition between adsorption motifs, and reproduce the experimentally dominant on-top [2+2] cycloaddition geometry. Our results show that fine-tuning of pre-trained foundational models enables statistically converged, chemically accurate simulations of bond-forming and bond-breaking events on complex surfaces, providing a scalable route to reconcile atomistic theory with experimental ensemble measurements in semiconductor functionalization.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
6 figures
Modulational instability of inter-spin-orbit coupled Bose-Einstein condensates in deep optical lattice
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-09-19 20:00 EDT
R. Sasireka, S. Sabari, A. Uthayakumar, Lauro Tomio
We present a comprehensive study of modulational instability (MI) in a binary Bose-Einstein condensate with spin-orbit coupling, confined to a deep optical lattice. The system is modeled by a set of discrete Gross-Pitaevskii equations. Using linear stability analysis, we derive the explicit MI conditions for the system, elucidating the critical and distinct roles played by spin-orbit coupling, inter-species nonlinearity, and intra-species nonlinearity. Our analysis, conducted for both unstaggered and staggered fundamental modes, reveals markedly different instability landscapes for these two configurations. The analytical predictions are confirmed by extensive numerical simulations of the full nonlinear dynamics, which vividly illustrate the spatiotemporal evolution of wave amplitudes, phase coherence, and energy localization during the instability process. The numerical results, obtained via a fourth-order Runge-Kutta method, show excellent agreement with the linear stability theory and provide a complete picture of the MI-induced pattern formation.
Quantum Gases (cond-mat.quant-gas)
15 pages, 11 figures
Minimal velocity of the travelling wave solutions in two coupled FKPP equations with the global conservation law
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-19 20:00 EDT
We investigate the system of two coupled one-dimensional Fisher-Kolmogorov-Petrovsky-Piskunov (FKPP) equations which possess the global conservation law. Such system of equations has been recently derived for the quasiparticle densities in the two-band fermionic model with the particle-number conserving dissipative protocol. As standard FKPP equation the studied system of equations has one unstable and one stable homogeneous solution with travelling wave switching between them. We demonstrate that the conservation law enforces the synchronization of travelling waves for both densities and determine their minimal possible velocity. Surprisingly, we find the existence of jumps of the minimal velocity as function of control parameters. We obtain that the minimal velocity of the coupled FKPP equations may significantly exceed the minimal velocity for a single FKPP equation in a wide range of control parameters.
Statistical Mechanics (cond-mat.stat-mech), Pattern Formation and Solitons (nlin.PS)
Bloch oscillations of helicoidal spin-orbit coupled Bose-Einstein condensates in deep optical lattices
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-09-19 20:00 EDT
Sumaita Sultana, Golam Ali Sekh
We consider helicoidal spin-orbit coupled Bose-Einstein condensates in deep optical lattice and study the dynamics of Bloch oscillation. We show that the variation of helicoidal gauge potential with spin-orbit coupling is different in zero-momentum and plane-wave phases. The characteristic of Bloch oscillation are different in the two phases. In the zero-momentum phase, the Bloch oscillation harmonic while it is anharminic in plane-wave phase. The amplitude of Bloch oscillation are found to be affected by the relative value of helicoidal gauge potential and spin-orbit coupling, and mean-field interaction. We examined that the decay of Bloch oscillation caused by mean-field interaction can be managed by helicoidal spin-orbit coupling.
Quantum Gases (cond-mat.quant-gas)
6 pages and 5 figures
Julia Set in Quantum Evolution: The case of Dynamical Quantum Phase Transitions
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-19 20:00 EDT
Manmeet Kaur, Somendra M. Bhattacharjee
Dynamical quantum phase transitions (DQPTs) are a class of
non-equilibrium phase transitions that occur in many-body quantum
systems during real-time evolution, rather than through parameter
tuning as in conventional phase transitions. This paper
presents an exact analytical approach to studying DQPTs by combining
complex dynamics with the real-space renormalization group (RG).
RG transformations are interpreted as iterated maps on the complex
plane, establishing a connection between DQPTs and the Julia set,
the fractal boundary separating the basins of attraction of the
stable fixed points. This framework is applied to a quantum quench in
the one-dimensional transverse field Ising model, and the
sensitivity of DQPTs to changes in boundary conditions is examined. In
particular, it is demonstrated how the topology of the spin chain influences
the occurrence of DQPTs. Additionally, aqualitative argument based on quantum
speed limits is provided to explain the suppression of DQPTs under certain
boundary modifications.
Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
10 pages
Investigating the Ferroelectric Potential Landscape of 3R-MoS$_2$ through Optical Measurements
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-19 20:00 EDT
Jan-Niklas Heidkamp, Johannes Schwandt-Krause, Swarup Deb, Kenji Watanabe, Takashi Taniguchi, Rico Schwartz, Tobias Korn
In recent years, sliding ferroelectricity has emerged as a topic of significant interest due to its possible application in non-volatile random access memory. This phenomenon is unique to two-dimensional van der Waals materials, where vertical ferroelectric polarization switching is induced by relative in-plane sliding of the constituent layers. The intrinsic stacking order influences the resulting polarization, creating distinct polarization regions separated by domain walls. These regions and the domain walls can be manipulated using an applied vertical electric field, enabling a switchable system that retains the environmental robustness of van der Waals materials under ambient conditions. This study investigates 3R-MoS$ _2$ using various optical measurement techniques at room temperature. The spatially resolved optical measurements reveal apparent signal changes corresponding to different ferroelectric stacking orders and variations in layer count. Our findings demonstrate that fast optical mapping at room temperature is a reliable method for probing ferroelectric potential steps in 3R-stacked MoS$ _2$ samples, thereby facilitating the identification of the ferroelectric configuration. This approach does not require a conductive substrate or an electrical contact to the sample, making it more versatile than traditional atomic force probe techniques.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Spin-polarised surface fermiology of ohmic WSe$_2$/NbSe$_2$ interfaces
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-19 20:00 EDT
Oliver J. Clark, Thi-Hai-Yen Vu, Ben A. Chambers, Federico Mazzola, Sadhana Sridhar, Geetha Balakrishnan, Aaron Bostwick, Chris Jozwiak, Eli Rotenberg, Sarah L. Harmer, Michael S. Fuhrer, Mark T. Edmonds
Discovering and engineering spin-polarised surface states in the electronic structures of condensed matter systems is a crucial first step in development of spintronic devices, wherein spin-polarised bands crossing the Fermi level can facilitate information transfer. Here, we show how the spin-orbit split K-point valleys of monolayer WSe$ _2$ can be made potentially suitable for this purpose, despite the semiconducting ground state. By interfacing with metallic 2H-NbSe$ _2$ , these valence band extrema are shifted by $ \sim$ 800~meV to produce a surface-localised Fermi surface populated only by spin-polarised carriers. By increasing the WSe$ _2$ thickness, the Fermi pockets can be moved from K to $ \Gamma$ , demonstrating tunability of novel semi-metallic phases that exist atop a substrate additionally possessing charge density wave and superconducting transitions. Together, this study provides spectroscopic understanding into $ p$ -type, Schottky barrier-free interfaces, which are of urgent interest for bypassing the limitations of current-generation vertical field effect transistors, in addition to longer-term spintronics development.
Materials Science (cond-mat.mtrl-sci)
7 pages, 4 figures
Ultrafast controlling net magnetization in g-wave altermagnets via laser fields
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-19 20:00 EDT
Zhaobo Zhou, Sangeeta Sharma, Junjie He
The diverse nodal spin structures in d/g/i-wave altermagnets (AM) may cause distinct light-induced spin responses yet remain poorly understood. Using time-dependent density functional theory (TDDFT), we reveal that laser induced ultrafast demagnetization dynamics in the g-wave AM CrSb are strongly governed by the laser incidence direction. Under normal incidence along the [0001] axis, two Cr sublattices exhibit symmetric temporal demagnetization but with different amplitudes, preserving the net-zero magnetization, unlike the behavior in d-wave AM. Off-normal incidence, however, induces pronounced asymmetric demagnetization between sublattices, transiently driving the system into a ferrimagnetic-like state with a sizable net magnetization. This direction-dependent response arises from the characteristic nodal structures in bulk g-wave AM electronic structure, which enable anisotropic optical intersite spin transfer (OISTR). By comparing g-wave and d-wave AMs, we propose that light-induced magnetization arises when laser polarization aligns with spin-uncompensated regions in electronic structures. This can be readily determined from the local spin density of states along specific band paths. Our results provide a fundamental understanding for laser-induced ultrafast dynamics in AM.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
Mapping Microstructure: Manifold Construction for Accelerated Materials Exploration
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-19 20:00 EDT
Simon A. Mason, Megna N. Shah, Jeffrey P. Simmons, Dennis M. Dimiduk, Stephen R. Niezgoda
Accelerating materials development requires quantitative linkages between processing, microstructure, and properties. In this work, we introduce a framework for mapping microstructure onto a low-dimensional material manifold that is parametrized by processing conditions. A key innovation is treating microstructure as a stochastic process, defined as a distribution of microstructural instances rather than a single image, enabling the extraction of material state descriptors that capture the essential process-dependent features. We leverage the manifold hypothesis to assert that microstructural outcomes lie on a low-dimensional latent space controlled by only a few parameters. Using phase-field simulations of spinodal decomposition as a model material system, we compare multiple microstructure descriptors (two-point statistics, chord-length distributions, and persistent homology) in terms of two criteria: (1) intrinsic dimensionality of the latent space, and (2) invertibility of the processing-to-structure mapping. The results demonstrate that distribution-based descriptors can recover a two-dimensional latent structure aligned with the true processing parameters, yielding an invertible and physically interpretable mapping between processing and microstructure. In contrast, descriptors that do not account for microstructure variability either overestimate dimensionality or lose predictive fidelity. The constructed material manifold is shown to be locally continuous, wherein small changes in process variables correspond to smooth changes in microstructure descriptors. This data-driven manifold mapping approach provides a quantitative foundation for microstructure-informed process design and paves the way toward closed-loop optimization of processing–structure–property relationships in an integrated materials engineering context.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
A causality-based divide-and-conquer algorithm for nonequilibrium Green’s function calculations with quantics tensor trains
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-19 20:00 EDT
Ken Inayoshi, Maksymilian Środa, Anna Kauch, Philipp Werner, Hiroshi Shinaoka
We propose a causality-based divide-and-conquer algorithm for nonequilibrium Green’s function calculations with quantics tensor trains. This algorithm enables stable and efficient extensions of the simulated time domain by exploiting the causality of Green’s functions. We apply this approach within the framework of nonequilibrium dynamical mean-field theory to the simulation of quench dynamics in symmetry-broken phases, where long-time simulations are often required to capture slow relaxation dynamics. We demonstrate that our algorithm allows to extend the simulated time domain without a significant increase in the cost of storing the Green’s function.
Strongly Correlated Electrons (cond-mat.str-el)
Submission to SciPost; 28 pages, 14 figures
Physics-Informed GCN-LSTM Framework for Long-Term Forecasting of 2D and 3D Microstructure Evolution
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-19 20:00 EDT
Hamidreza Razavi, Nele Moelans
This paper presents a physics-informed framework that integrates graph convolutional networks (GCN) with long short-term memory (LSTM) architecture to forecast microstructure evolution over long time horizons in both 2D and 3D with remarkable performance across varied metrics. The proposed framework is composition-aware, trained jointly on datasets with different compositions, and operates in latent graph space, which enables the model to capture compositions and morphological dynamics while remaining computationally efficient. Compressing and encoding phase-field simulation data with convolutional autoencoders and operating in Latent graph space facilitates efficient modeling of microstructural evolution across composition, dimensions, and long-term horizons. The framework captures the spatial and temporal patterns of evolving microstructures while enabling long-range forecasting at reduced computational cost after training.
Materials Science (cond-mat.mtrl-sci), Computational Engineering, Finance, and Science (cs.CE), Machine Learning (cs.LG), Computational Physics (physics.comp-ph)
Towards a deeper fundamental understanding of (Al,Sc)N ferroelectric nitrides
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-19 20:00 EDT
Peng Chen, Dawei Wang, Alejandro Mercado Tejerina, Keisuke Yazawa, Andriy Zakutayev, Charles Paillard, Laurent Bellaiche
Density Functional Theory (DFT) calculations, within the virtual crystal alloy approximation, are performed, along with the development of a Landau-type model employing a symmetry-allowed analytical expression of the internal energy and having parameters being determined from first principles, to investigate properties and energetics of Al1-xScxN ferroelectric nitrides in their hexagonal forms. These DFT computations and this model predict the existence of two different types of minima, namely the 4-fold-coordinated wurtzite (WZ) polar structure and a 5-times paraelectric hexagonal phase (to be denoted as H5), for any Sc composition up to 40%. The H5 minimum progressively becomes the lowest energy state within hexagonal symmetry as the Sc concentration increases from 0 to 40%. Furthermore, the model points out to several key findings. Examples include the crucial role of the coupling between polarization and strains to create the WZ minimum, in addition to polar and elastic energies, and that the origin of the H5 state overcoming the WZ phase as the global minimum within hexagonal symmetry when increasing the Sc composition mostly lies in the compositional dependency of only two parameters, one linked to the polarization and another one being purely elastic in nature. Other examples are that forcing Al1-xScxN systems to have no or a weak change in lattice parameters when heating them allows to reproduce well their finite-temperature polar properties, and that a value of the axial ratio close to that of the ideal WZ structure does imply a large polarization at low temperatures but not necessarily at high temperatures because of the ordered-disordered character of the temperature-induced formation of the WZ state. Such findings should allow for a better fundamental understanding of (Al,Sc)N ferroelectric nitrides, which may be used to design efficient devices operating at low voltages.
Materials Science (cond-mat.mtrl-sci)
Layer-Dependent Spin Properties of Charge Carriers in Vertically Coupled Telecom Quantum Dots
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-19 20:00 EDT
Marius Cizauskas, A. Kors, J. P. Reithmaier, A. M. Fox, M. Benyoucef, Manfred Bayer, Alex Greilich
We investigate the spin properties of charge carriers in vertically coupled InAs/InAlGaAs quantum dots grown by molecular beam epitaxy, emitting at telecom C-band wavelengths, with a silicon $ \delta$ -doped layer. Using time-resolved pump-probe Faraday ellipticity measurements, we systematically study single-, two-, and four-layer quantum dot (QD) configurations to quantify how vertical coupling affects key spin-coherence parameters. Our measurements reveal distinct layer-dependent effects: (1) Adding a second QD layer flips the resident charge from electrons to holes, consistent with optically induced electron tunneling into lower-energy dots and resultant hole charging. (2) Starting from the four-layer sample, the pump-probe signal develops an additional non-oscillating, decaying component absent in single- and two-layer samples, attributed to multiple layer growth changing the strain environment, which reduces heavy-hole and light-hole mixing. (3) With four-layers or more, hole spin mode locking (SML) can be observed, enabling quantitative extraction of the hole coherence time $ T_2 \approx 13$ ,ns from SML amplitude saturation. We also extract longitudinal spin relaxation ($ T_1$ ) and transverse ($ T_2^\ast$ ) spin dephasing times, g-factors, and inhomogeneous dephasing parameters for both electrons and holes across all layer configurations. The hole spin dephasing times $ T_2^\ast$ remain relatively constant (2.26-2.73,ns) across layer counts, while longitudinal relaxation times $ T_1$ decrease with increasing layers (from 1.03,$ \mu$ s for single-layer to 0.31,$ \mu$ s for four-layer samples). These findings provide potential design guidelines for engineering spin coherence in telecom-band QDs for quantum information applications.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Accurate measurement of energy relaxation via flux-flow instability
New Submission | Superconductivity (cond-mat.supr-con) | 2025-09-19 20:00 EDT
E. M. Baeva, N. A. Titova, M. A. Kirsanova, S.A. Evlashin, A. V. Semenov, D. Yu. Vodolazov, A. I. Kolbatova, G.N. Goltsman
In this paper, we investigate flux-flow instability (FFI) in a superconducting single-crystal titanium nitride (TiN) film with negligible volume pinning. By studying the critical current density in 12-nm thick TiN strips of varying widths, we accurately identify the experimental parameters at which the FFI regime occurs. A comprehensive analysis of critical velocity measurements allows us to determine the quasiparticle energy relaxation time, $ \tau_E$ . By comparing our results with the $ \tau_E$ values obtained from other experimental methods, we gain insight into the dominant microscopic process that governs quasiparticle relaxation within the vortex core in TiN. This mechanism is driven by an increase in quasiparticle temperature relative to phonons, rather than by quasiparticles leaving the core. Our findings indicate that $ \tau_E$ can be accurately determined through FFI measurements.
Superconductivity (cond-mat.supr-con)
10 pages, 8 figures
A pedestrian’s approach to large deviations in semi-Markov processes with an application to entropy production
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-19 20:00 EDT
Alexander M. Maier, Jonas H. Fritz, Udo Seifert
Semi-Markov processes play an important role in the effective description of partially accessible systems in stochastic thermodynamics. They occur, for instance, in coarse-graining procedures such as state lumping and when analyzing waiting times between few visible Markovian events. The finite-time measurement of any coarse-grained observable in a stochastic system depends on the specific realization of the underlying trajectory. Moreover, the fluctuations of such observables are encoded in their rate function that follows from the rate function of the empirical measure and the empirical flow in the respective process. Derivations of the rate function of empirical measure and empirical flow in semi-Markov processes with direction-time independence (DTI) exist in the mathematical literature, but have not received much attention in the stochastic thermodynamics community. We present an accessible derivation of the rate function of the tuple frequency in discrete-time Markov chains and extend this to the rate function of the empirical semi-Markov kernel in semi-Markov processes without DTI. From this, we derive an upper bound on the rate function of the empirical entropy production rate, which leads to a lower bound on the variance of the mean entropy production rate measured along a finite-time trajectory. We illustrate these analytical bounds with simulated data.
Statistical Mechanics (cond-mat.stat-mech)
Superconductivity in W3Re2C with chiral structure
New Submission | Superconductivity (cond-mat.supr-con) | 2025-09-19 20:00 EDT
Lei Yang, Jing Jiang, Hui-Hui He, Kai Liu, Hechang Lei
We discover superconductivity in cubic W3Re2C with chiral structure and the superconducting transition temperature Tc is about 6.2 K. Detailed characterizations and analysis indicate that W3Re2C is a bulk type-II BCS superconductor with full isotropic gap. Moreover, first-principles calculations indicate that the electron-phonon coupling primarily arises from interactions between W/Re 5d electronic states and their low-frequency phonons. Furthermore, the breaking of inversion symmetry in W3Re2C facilitates the emergence of Weyl points in the electronic structure. Therefore, W3Re2C can serve as a promising platform for investigating the influences of chiral structure on both superconductivity and band topology.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
7 pages and 5 figures
Sub-tesla on-chip nanomagnetic metamaterial platform for angle-resolved photoemission spectroscopy
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-19 20:00 EDT
Wenxin Li, Wisha Wanichwecharungruang, Mingyang Guo, Ioan-Augustin Chioar, Nileena Nandakumaran, Justin Ramberger, Senlei Li, Zhibo Kang, Jinming Yang, Donghui Lu, Makoto Hashimoto, Chunhui Rita Du, Chris Leighton, Peter Schiffer, Qiong Ma, Ming Yi, Yu He
Magnetically controlled states in quantum materials are central to their unique electronic and magnetic properties. However, direct momentum-resolved visualization of these states via angle-resolved photoemission spectroscopy (ARPES) has been hindered by the disruptive effect of magnetic fields on photoelectron trajectories. Here, we introduce an \textit{in-situ} method that is, in principle, capable of applying magnetic fields up to 1 T. This method uses substrates composed of nanomagnetic metamaterial arrays with alternating polarity. Such substrates can generate strong, homogeneous, and spatially confined fields applicable to samples with thicknesses up to the micron scale, enabling ARPES measurements under magnetic fields with minimal photoelectron trajectory distortion. We demonstrate this minimal distortion with ARPES data taken on monolayer graphene. Our method paves the way for probing magnetic field-dependent electronic structures and studying field-tunable quantum phases with state-of-the-art energy-momentum resolutions.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
Diagrammatic bosonisation, aspects of criticality, and the Hohenberg-Mermin-Wagner Theorem in parquet approaches
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-19 20:00 EDT
The parquet equations present a cornerstone of some of the most important diagrammatic many-body approximations and methods currently on the market for strongly correlated materials: from non-local extensions of the dynamical mean-field theory to the functional renormalization group. The recently introduced single-boson exchange decomposition of the vertex presents an alternative set of equivalent equations in terms of screened interactions, Hedin vertices, and rest functions. This formulation has garnered much attention for several reasons: opening the door to new approximations, for avoiding vertex divergences associated with local moment formation plaguing the traditional parquet decomposition, and for its interpretative advantage in its built-in diagrammatic identification of bosons without resorting to Hubbard-Stratonovich transformations. In this work, we show how the fermionic diagrams of the particle-particle and particle-hole polarizations can be mapped to diagrammatics of a bosonic self-energy of two respective bosonic theories with pure bosonic constituents, solidifying the identification of the screened interaction with a bosonic propagator. Resorting to a spin-diagonalized basis for the bosonic fields and neglecting the coupling between singlet and triplet components is shown to recover the trace log theory known from Hubbard-Stratonovich transformations. Armed with this concrete mapping, we revisit a conjecture claiming that universal aspects of the parquet approximation coincide with those of the self-consistent screening approximation for a bosonic $ O(N)$ model. We comment on the role of the self-energy and crossing symmetry in enforcing the Hohenberg-Mermin-Wagner theorem in parquet-related approaches.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci), Statistical Mechanics (cond-mat.stat-mech)
24 pages, 20 figures. comments welcome
Zero Indirect Band Gap in Non-Hermitian Systems
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-19 20:00 EDT
Zero indirect gaps in band models are typically viewed as unstable and achievable only through fine-tuning. Recent works, however, have revealed robust semimetallic phases in Hermitian systems where the indirect gap remains pinned at zero over a finite parameter range. Here, we extend this paradigm to non-Hermitian lattice models by studying a one-dimensional diamond-like system with gain and loss. We show that a zero indirect band gap can remain stable against non-Hermitian perturbations and identify the regimes where this robustness persists. Remarkably, we find that the zero indirect gap induces a suppression of the non-Hermitian skin effect distinct from other physical mechanics already discussed in the literature. Our results reveal new connections between indirect gaps, exceptional points and non-Hermitian skin effect, opening avenues for experimental realizations.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Optics (physics.optics), Quantum Physics (quant-ph)
Bichromatic Moiré Superlattices for Tunable Quadrupolar Trions and Correlated States
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-19 20:00 EDT
Mingfeng Chen, Runtong Li, Haonan Wang, Yuliang Yang, Yiyang Lai, Chaowei Hu, Takashi Taniguchi, Kenji Watanabe, Jiaqiang Yan, Jiun-Haw Chu, Erik Henriksen, Chuanwei Zhang, Li Yang, Xi Wang
Moiré superlattices in transition metal dichalcogenide heterostructures provide a platform to engineer many-body interactions. Here, we realize a bichromatic moiré superlattice in an asymmetric WSe$ _2$ /WS$ _2$ /WSe$ _2$ heterotrilayer by combining R- and H-stacked bilayers with mismatched moiré wavelengths. This structure hosts fermionic quadrupolar moiré trions–interlayer excitons bound to an opposite-layer hole–with vanishing dipole moments. These trions arise from hybridized moiré potentials enabling multiple excitonic orbitals with tunable interlayer coupling, allowing control of excitonic and electronic ground states. We show that an out-of-plane electric field could effectively reshape moiré excitons and interlayer-intralayer electron correlations, driving a transition from interlayer to intralayer Mott states with enhanced Coulomb repulsion. The asymmetric stacking further enriches excitonic selection rules, broadening opportunities for spin-photon engineering. Our results demonstrate bichromatic moiré superlattices as a reconfigurable platform for emergent quantum states, where quadrupolar moiré trion emission may enable coherent and entangled quantum light manipulation.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
Accelerated Discovery of Topological Conductors for Nanoscale Interconnects
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-19 20:00 EDT
Alexander C. Tyner, William Rogers, Po-Hsin Shih, Yi-Hsin Tu, Gengchiau Liang, Hsin Lin, Ching-Tzu Chen, James M. Rondinelli
The sharp increase in resistivity of copper interconnects at ultra-scaled dimensions threatens the continued miniaturization of integrated circuits. Topological semimetals (TSMs) with gapless surface states (Fermi arcs) provide conduction channels resistant to localization. Here we develop an efficient computational framework to quantify 0K surface-state transmission in nanowires derived from Wannier tight-binding models of topological conductors that faithfully reproduce relativistic density functional theory results. Sparse matrix techniques enable scalable simulations incorporating disorder and surface roughness, allowing systematic materials screening across sizes, chemical potentials, and transport directions. A dataset of 3000 surface transmission values reveals TiS, ZrB$ _{2}$ , and nitrides AN where A=(Mo, Ta, W) as candidates with conductance matching or exceeding copper and benchmark TSMs NbAs and NbP. This dataset further supports machine learning models for rapid interconnect compound identification. Our results highlight the promise of topological conductors in overcoming copper’s scaling limits and provide a roadmap for data-driven discovery of next-generation interconnects.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
12 + 111 pages, 6 + 6 figures
Building high-energy silicon-containing batteries using off-the-shelf materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-19 20:00 EDT
Marco-Tulio F. Rodrigues, Stephen E. Trask, Alison R. Dunlop, Yi-Chen Lan, Joseph Kubal, Devashish Salpekar, Andressa Y. R. Prado, Evelyna Wang, Charles McDaniel, Eliot F. Woods, Lily A. Robertson, Ryan J. Tancin, Maxwell C. Schulze, Nicolas Folastre, Baris Key, Zhengcheng Zhang, Wenquan Lu, Daniel P. Abraham, Andrew N. Jansen
The technology of silicon anodes appears to be reaching maturity, with high-energy Si cells already in pilot-scale production. However, the performance of these systems can be difficult to replicate in academic settings, making it challenging to translate research findings into solutions that can be implemented by the battery industry. Part of this difficulty arises from the lack of access to engineered Si particles and anodes, as electrode formulations and the materials themselves have become valuable intellectual property for emerging companies. Here, we summarize the efforts by Argonne’s Cell Analysis, Modeling, and Prototyping (CAMP) Facility in developing Si-based prototypes made entirely from commercially available materials. We describe the many challenges we encountered when testing high-loading electrodes (> 5 mAh/cm2) and discuss strategies to mitigate them. With the right electrode and electrolyte design, we show that our pouch cells containing > 70 wt% SiOx can achieve 600-1,000 cycles at C/3 and meet projected energy targets of 700 Wh/L and 350 Wh/kg. These results provide a practical reference for research teams seeking to advance silicon-anode development using accessible materials.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
Competing and Intertwined Orders in Boson-Doped Mott Antiferromagnets
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-19 20:00 EDT
Xin Lu, Jia-Xin Zhang, Lukas Homeier, Hong-Chen Jiang, Shou-Shu Gong, D. N. Sheng, Zheng-Yu Weng
Inspired by the recent experimental advances in cold atom quantum simulators, we explore the experimentally implemented bosonic $ t$ -$ t’$ -$ J$ model on the square lattice using large-scale density matrix renormalization group simulations. By tuning the doping level $ \delta$ and hopping ratio $ t’/t$ , we uncover six distinct quantum phases, several of which go far beyond the conventional paradigm of phase-coherent superfluidity (SF) expected for bosonic systems. In particular, in the presence of antiferromagnetic (AFM) order, doped holes are tightly bound into pairs, giving rise to a pair density wave (PDW) phase at low doping and small $ |t’/t|$ , which is suppressed on the $ t’<0$ side, resulting in a disordered PDW state that lacks coherence of either individual bosons or pairs. Upon further doping, bosons can regain phase coherence and form a SF\ast state, characterized by condensation at emergent incommensurate momenta concurrent with an incommensurate magnetic order. On the $ t’>0$ side, the sign-induced kinetic frustration inherently disfavors local AFM correlations, leading to a phase separation in which doped holes cluster into ferromagnetic (FM) domains spatially separated by undoped AFM regions. Upon further doping, this inhomogeneous state evolves into a uniform SF + $ xy$ -FM phase. Finally, we propose a concrete experimental scheme to realize both signs of $ t’/t$ in Rydberg tweezer arrays, with an explicit mapping between model parameters and experimentally accessible regimes. Our results reveal competing and intertwined orders in doped antiferromagnets, which are relevant to central issues in high-$ T_c$ superconductivity, reflecting the frustrated interplay between doped holes and spin background.
Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con)
25 pages, 22 figures