Statistical Mechanics
Diffusing diffusivity model with dichotomous noise
Dongho Lee, Jae-Hyung Jeon, Pascal Viot et al. (+1 more)
We study Langevin dynamics with
stochastic diffusivity arising from fluctuations of the surrounding medium. The diffusivity is modeled as Ornstein-Uhlenbeck process driven by symmetric dichotomous noise, which confines it to a finite interval. We derive analytical expressions for the short-time probability density function (PDF) of the particle displacement and analyse its asymptotic behaviour. While the PDF retains the characteristic logarithmic divergence at the origin, its tails differ from the Gaussian white-noise case: exponential tails are replaced by Gaussian ones modulated by a power-law with a switching-rate-dependent exponent. At long times, the dynamics converges to ordinary Gaussian
diffusion. We determine the variance and covariance of the time-averaged
stochastic diffusivity and show that it is self-averaging. The model provides a minimal analytically tractable framework for
stochastic transport in environments with bounded or switching fluctuations.
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All authors Dongho Lee, Jae-Hyung Jeon, Pascal Viot, Gleb Oshanin
Quantum Gases · Cross-listed from quant-ph
Many-Body Super- and Subradiance in Ordered Atomic Arrays
Alec Douglas, Lin Su, Michal Szurek et al. (+7 more)
When
quantum emitters couple indistinguishably to light, they can synchronize into a collective light matter system with radiative properties profoundly different from those of independent particles. To date, the resulting collective effects have largely been confined to point like or homogeneous ensembles. Here, we open access to a qualitatively new collective regime by realizing geometrically ordered, spatially extended atom arrays with subwavelength spacing. This establishes a fundamentally new platform in which collective emission is no longer confined to a single Dicke mode but instead emerges from an ordered network of
photon mediated interactions. We find that 2D atom arrays undergo strong super and subradiant emission. Despite subwavelength spacing, we achieve site resolved imaging and directly observe the buildup of spatial correlations, demonstrating the transformation of cooperative decay into a strongly correlated many-body process. We observe extensive scaling of superradiance, uncover superradiant revivals, and reveal the
ferromagnetic nature of superradiance and the
antiferromagnetic nature of subradiance. Our results realize a novel programmable platform for exploring and utilizing dissipative many-body
quantum physics, opening new possibilities for
photon capture, storage, and atom
photon entanglement.
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All authors Alec Douglas, Lin Su, Michal Szurek, Robin Groth, Sandra Brandstetter, Ognjen Marković, Oriol Rubies-Bigorda, Stefan Ostermann, Susanne F. Yelin, Markus Greiner
Materials Science
Multiple spiking functionalities in annealing-optimized Ag/Hf$_{0.5}$Zr$_{0.5}$O$_2$-based memristive neurons
Nikita Zhidkov, Andrei Zenkevich and Anton Khanas
Rapid progress of artificial neural network applications in recent years has led to the issue of an unprecedented energy consumption. It can be solved by the implementation of energy efficient hardware based on non-von-Neumann architectures, which requires the development of electronic components emulating the behavior of synapses and
neurons. While research of synaptic elements is vast, the technology for fabrication of scalable and highly reproducible neuronal elements is far less developed. In this paper, we demonstrate an artificial
neuron with multiple functionalities based on filamentary switching Ag/Hf$_{0.5}$Zr$_{0.5}$O$_2$ (HZO) memristors. To improve the parameters of memristors, we propose a two-step annealing method, which allows for better control of the crystallization of the functional dielectric layer (HZO) as well as of the
diffusion of active electrode (Ag) atoms. Furthermore, we demonstrate the leaky integrate-and-fire (LIF) neuronal behavior in multiple spiking modes: time-to-first-spike (TTFS), number of spikes and firing rate coding. Moreover, the
neuron operation does not require the additional electronic overhead and is supported solely by a Ag/HZO memristor with a current limiting resistor connected in series. The presented results pave the way for the creation of next generation energy efficient neuromorphic hardware operating on the principles of spiking neural networks.
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Materials Science · Cross-listed from cs.LG
Autonomous Diffractometry Enabled by Visual Reinforcement Learning
J. Oppliger, M. Stifter, A. Rüegg et al. (+7 more)
Automation underpins progress across scientific and industrial disciplines. Yet, automating tasks requiring interpretation of abstract visual information remain challenging. For example,
crystal alignment strongly relies on humans with the ability to comprehend diffraction patterns. Here we introduce an autonomous system that aligns single
crystals without access to crystallography and diffraction theory. Using a model-free reinforcement learning framework, an
agent learns to identify and navigate towards high-
symmetry orientations directly from Laue diffraction patterns. Despite the absence of human supervision, the
agent develops human-like strategies to achieve time-efficient
alignment across different
crystal symmetry classes. With this, we provide a computational framework for intelligent diffractometers. As such, our approach advances the development of automated experimental workflows in materials science.
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All authors J. Oppliger, M. Stifter, A. Rüegg, I. Biało, L. Martinelli, P. G. Freeman, D. Prabhakaran, J. Zhao, Q. Wang, J. Chang
Mesoscale and Nanoscale Physics · Cross-listed from physics.optics
Magnetic switching of self-hybridized exciton-polaritons in CrSBr photonic crystal slabs
T. D. Gorelkina, I. E. Kalantaevskii, A. N. Abramov et al. (+8 more)
Layered van der Waals antiferromagnet CrSBr supports strong light–matter coupling and formation of magnetically tunable
exciton-polaritons, yet active
magnetic control over polariton propagation direction has remained elusive. Here, we investigate self-hybridized
exciton-polaritons in photonic
crystal slabs fabricated from CrSBr flakes and their
evolution across the
antiferromagnetic-to-
ferromagnetic spin-flip transition induced by moderate in-plane
magnetic fields. Using angle-resolved reflectance and photoluminescence spectroscopy supported by modeling, we show that the polariton energy continuously tracks the layer-by-layer magnetization switching, revealing a gradual redistribution of oscillator strength from
antiferromagnetic to
ferromagnetic excitons near the critical field. Most notably, we demonstrate that the sign of the polariton group velocity can be reversed by a small change in the external
magnetic field of only 40 mT, resulting in complete switching of the polariton propagation direction. Our results establish CrSBr photonic
crystal slabs as a platform for magnetically controlled polariton transport, opening opportunities for active integrated photonic and polaritonic devices.
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All authors T. D. Gorelkina, I. E. Kalantaevskii, A. N. Abramov, K. A. Gasnikova, P. A. Alekseev, X. Zeng, D. Huang, T. Jiang, I. V. Iorsh, I. Y. Chestnov, V. Kravtsov
Quantum Gases · Cross-listed from physics.flu-dyn
Schrödinger-Navier-Stokes equation for capillary fluids
Luca Salasnich, Simon Böhly, Sauro Succi et al. (+1 more)
We highlight some properties of the Schrödinger-Navier-Stokes (SNS) equation [Salasnich, Succi, and Tiribocchi (2024)] of potential relevance for microfluidics and soft matter. Specifically, we show that the SNS equation with generic parameters is formally equivalent to the Navier-Stokes-Korteweg equations for capillary fluids, with the equivalence established at the level of an action functional that decomposes naturally into a Korteweg conservative and a dissipative contribution. We derive the dispersion relation for sound modes, showing that the dispersive parameter controls capillary stiffness while the dissipative parameter controls viscous damping, and that the Bogoliubov dispersion relation is recovered in the
quantum limit. We also derive an effective one-dimensional SNS equation for a fluid confined in a narrow capillary tube.
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All authors Luca Salasnich, Simon Böhly, Sauro Succi, Adriano Tiribocchi
Soft Condensed Matter
An active soft condensed matter approach to the Physics of living systems
Nitin Kumar
This article aims to introduce the broad field of soft active matter physics and its relevance to the life sciences in simple, accessible
language. Although this area of research is relatively new, it has already demonstrated significant potential in providing a physical understanding of many biological processes. While several review articles by leading researchers exist, they can be difficult to grasp for undergraduate students and even early-career researchers who wish to enter this field. In this article, I cover the basics, introduce the origins of soft active matter physics, and explain how it differs from traditional
equilibrium condensed matter ideas at the fundamental level. For the most part, I will avoid mathematical equations and excessive technical precision in several statements. Instead, I will focus on communicating the core ideas and the overall spirit of the argument, using everyday examples to develop a physical intuition. The primary focus will be on the dynamical aspects of these systems. I will conclude by briefly discussing a published experimental study from our research group that examines universal features of the trajectories of homing and migrating organisms.
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Strongly Correlated Electrons
Topological Kondo Insulator from Spin Loop Currents
Andreas Gleis, Kevin Lucht, Po-Jui Chen et al. (+3 more)
We demonstrate that interacting electrons in AB-stacked $\mathrm{MoTe}_2/\mathrm{WSe}_2$ realize a topological Kondo
insulator at hole filling $\nu=2$ per moiré unit
cell. In the presence of only local correlations, a
symmetry of the moiré-scale bandstructure enforces a compensated topological semimetal by tying band inversion to band overlap. We show that non-local interactions change the physics qualitatively, since they allow intrinsic,
quantum-geometry-induced
spin loop currents to feed back on the effective bandstructure, which lift the remaining accidental degeneracies and open a full gap in the spectrum, leading to a fully gapped topological Kondo
insulator. We establish this using real-frequency dynamical mean-field theory to capture Kondo physics alongside Hartree-Fock for non-local interactions. The topological Kondo
insulator emerges at intermediate displacement fields, where strong correlations manifest through an enhanced
spin susceptibility, a suppressed charge susceptibility, and a stronger thermal dependence of the resistivity. Our results are in good agreement with recent experiments on $\mathrm{MoTe}_2/\mathrm{WSe}_2$
bilayers demonstrating topological to trivial phase transitions controlled by the displacement field.
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All authors Andreas Gleis, Kevin Lucht, Po-Jui Chen, Daniele Guerci, Andrew J Millis, J. H. Pixley
Superconductivity
Reduced pair breaking from extended disorder in unconventional superconductors: implications to 4Hb-TaS$_2$
Yuval Tsur, Mark H. Fischer and Jonathan Ruhman
Unconventional superconductivity is generally expected to be strongly suppressed by nonmagnetic disorder, as captured by Abrikosov–Gor'kov (AG) theory. However, several materials, including transition metal dichalcogenides, exhibit signatures of unconventional pairing despite relatively high resistivities, suggesting a breakdown of the conventional relation between momentum relaxation and pair breaking. Here, we study this problem in H-phase transition metal dichalcogenides by computing the disorder-dressed pairing susceptibility. We employ a multiband model with
spin-orbit coupling and include an
impurity potential that mimics a common
lattice defect, namely a chalcogen vacancy or site ad-atom. This yields to an extended
impurity potential, which we compare with the commonly considered on-site (point defect) potential. We evaluate the momentum-relaxation rate and the pair-breaking rate on equal footing. We find that extended
impurity potentials lead to a parametrically reduced pair-breaking rate compared to the transport scattering rate, with $\Gamma \tau_D \sim 1/3$ over a wide parameter range. This reduction originates from the momentum structure of the disorder potential, which partially matches the internal structure of the superconducting gap and suppresses pair-breaking processes. As a result, unconventional pairing states are significantly more robust than predicted by standard AG theory. Our results provide a natural explanation for the persistence of unconventional superconductivity in systems with strong disorder and substantially alleviate the apparent conflict between high resistivity and unconventional pairing in materials such as 4Hb-TaS$_2$.
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Mesoscale and Nanoscale Physics · Cross-listed from quant-ph
First-principles study of dispersive readout in circuit QED
Angela Riva, Prakritish Gogoi, Nicolas Gheeraert et al. (+4 more)
The speed and fidelity of dispersive readout of superconducting
qubits should improve by increasing the amplitude of the measurement drive. Experiments show, however, that beyond some drive amplitude there is always a saturation or drop in fidelity, often associated with a decrease in
qubit energy relaxation time $T_1$. A simple Lindblad master equation does not capture the latter effect. More involved approaches based on effective master equations rely on strong assumptions about the spectra of the system and the bath and only partially agree with observations. Here, we perform a first-principles simulation of the full
unitary dynamics of dispersive readout by considering the
circuit QED
Hamiltonian coupled to a microscopic model for the measurement transmission line, allowing for its arbitrary spectrum, including filters. Our access to the dynamics of the bath degrees of freedom allows us to investigate the emission spectrum of the system as a function of drive power. We show how the dependence of
qubit $T_1$ on readout drive amplitude is sensitive to the details of the bath spectrum. In particular, we find that $T_1$ drops with increasing drive amplitude when a Purcell notch filter is placed at the
qubit frequency, and that the Lindblad master equation shows general qualitative defects compared to the first-principles model.
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All authors Angela Riva, Prakritish Gogoi, Nicolas Gheeraert, Serge Florens, Alex W. Chin, Alain Sarlette, Alexandru Petrescu
Statistical Mechanics
Thermodynamic fluctuations in freely jointed chains under force
Michael R. Buche and Alvin Chen
It is common to study
polymer physics through the use of idealized single-chain models, and the most popular of these is the freely jointed chain model. In certain thermodynamic ensembles, statistical mechanical treatment of this model is analytically tractable or sometimes exactly solvable. This enables useful relations to be ascertained, like the expected chain end-to-end length as a function of an applied force. However, most of these relations return ensemble averages, which are values with inherent uncertainty, as opposed to deterministic values with no variance. This is an important distinction to understand and quantify, because the majority of studies to date involving single-chain models effectively treat these values as deterministic rather than fluctuating. To address this issue, thermodynamic fluctuations are examined in the freely jointed chain model. Specifically, the probability densities and standard deviations of the longitudinal, lateral, transverse, and radial portions of the chain extension, as well as the extension and link angles, are examined for different numbers of links and applied forces. Fluctuations in these quantities are shown to be considerable until the applied force becomes large. Increasing the number of links in the chain gradually reduces fluctuations in all quantities except for the link angles, since they are independent for freely jointed chains in the isotensional ensemble. Quantities are obtained analytically whenever possible and numerically otherwise. Overall, these results provide intuitive admonitions to consider when modeling the stretching of single
polymer chains or the deformation of entire
polymer networks.
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Soft Condensed Matter
Effect of Pre-Shear and Dispersity on Crystallization of a Model Polymer with Soft Pair Interactions using Molecular Dynamics Simulations
Tzortzis Koulaxizis and Antonia Statt
Polymer crystallization is a process of great interest in both fundamental theory and industrial settings, particularly in
polymer processing and applications involving semi-crystalline materials. The effect of processing on the initial stages of crystallization is not fully understood. Our study investigates the influence of pre-shear on monodisperse melts and bidisperse blends of a generic, segmentally coarse-grained
polymer model. Through molecular dynamics simulations, we explore how polydispersity affects crystallization, where we found that the addition of short chains to a melt of longer chains increased the final crystallinity by about 10%, and increased the initial growth rate by roughly a factor of two. In contrast, however, pre-shearing the hot melt before quenching only showed a minor increase in both growth rates and final crystallinty, except in monodisperse melts of short chains.
Crystal grain shapes were most influenced by pre-shearing monodisperse melts, where both asphericity and prolateness decreased. Additionally, we determined topological connectivity of
crystal grains through tie- and loop-chain analysis. Again, only monodisperse melts showed a significant increase of tie chain fractions with pre-shear, while all other systems showed only modest increases. Our findings provide insight into the changes of crystallinity and cluster morphologies that emerge when pre-sheared, offering a deeper understanding of the initial crystallization processes in
polymer melts when subjected to pre-shear.
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Strongly Correlated Electrons
Strongly correlated model of acousticlike plasmons persisting across the phase diagram of cuprate superconductors
Luciano Zinni, Hiroyuki Yamase, Matthias Hepting et al. (+2 more)
Layered two-dimensional electron systems exhibit both optical and acousticlike plasmons around the Brillouin-zone center. In the layered cuprate La$_{2-x}$Sr$_x$CuO$_4$, resonant inelastic x-ray scattering (RIXS) has detected corresponding acousticlike plasmons in a low-energy regime comparable to that of other collective excitations associated with distinct regions of the cuprate phase diagram. This overlap in energy scale raises the question of whether the acousticlike plasmons are significantly influenced by phase-specific electronic phenomena, including the pseudogap, charge and
spin order, superconductivity, and strange-metal behavior. Here we show that a single parameter set of the layered $t$-$J$-$V$ model, which incorporates strong correlations and the long-range Coulomb interaction $V$, consistently describes the acousticlike plasmon dispersion across all currently available RIXS data from the underdoped to the heavily overdoped regime. This transferability of a single parameter set exceeds that of earlier theoretical descriptions and supports a picture in which strong correlations persist into the heavily overdoped regime, while the collective plasmon mode exhibits only limited sensitivity to the phase-specific electronic phenomena that distinguish different regions of the phase diagram.
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All authors Luciano Zinni, Hiroyuki Yamase, Matthias Hepting, Matías Bejas, Andrés Greco
Superconductivity
Statistical Signatures of Majorana Zero Modes in Disordered Topological Superconductor Antidot Vortices
Zhibo Ren and Jukka I. Väyrynen
An antidot-pinned
vortex in a three-dimensional topological
insulator-
superconductor platform hosts a Majorana zero mode (MZM). However, numerous Caroli-de Gennes-Matricon (CdGM) states coexist with it. We develop a general theory to study the effects of disorder on the system, emphasizing the difference between Majorana zero mode and CdGM states. Using both an analytical random
matrix theory approach and numerical simulations, we derive the statistical distributions of these states. Our results demonstrate that the variance of the MZM probability density is twice that of the CdGM states, a difference due to the former having a real wave function as opposed to a complex one. This distinction can be measured by using scanning tunneling microscopy in a disordered antidot
vortex, providing a signature of MZM beyond the zero-bias conductance peak.
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Mesoscale and Nanoscale Physics
Geometry-controlled magnon-polaritons of double magnetic films in planar cavities
S. Solihin, Ahmad R. T. Nugraha and Muhammad Aziz Majidi
Planar cavity magnonics has been developed mainly for a single
magnetic film, leaving multilayer behavior in spatially resolved cavity scattering largely unexplored. Here, we introduce a double layer planar cavity with two
magnetic films embedded in the same microwave cavity to derive a full two-film scattering theory in the macrospin ($J = 0$) limit and recover the exact zero-gap half-thickness limit, thereby benchmarking the model against the known one-film result. We find that the double layer model actively enables geometry-controlled bright-channel enhancement, demonstrating that the
magnon-
photon coupling depends on spatial placement rather than just total
magnetic volume. Antinode-compatible placements increase the coupling, while node-compatible placements suppress it. Weak
symmetry breaking also transfers finite cavity weight to a mode dark in the symmetric limit, producing an additional branch without destroying the main avoided crossing. Finally, a reduced multimode theory for $J\neq 0$ predicts family-resolved bright and dark channels for odd standing-
spin-wave modes.
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Soft Condensed Matter
Kinematic and rheological equivalence of steady shearing and planar extensional flows
Nicholas King and Gareth H. McKinley
Steady shearing and planar extension are commonly viewed as two distinct types of flow field, especially in the context of probing the rheology of complex fluids. By leveraging the kinematic equivalence between the two flows, we derive an effective extension rate experienced by a material element which removes the rotational component of the shearing flow. This enables reconstruction of the steady planar extensional viscosity of an unknown fluid using only material functions measured in a steady shearing flow, revealing a deep rheological equivalence between the two deformation histories. We demonstrate this equivalency through phenomenological and microscopically motivated frame-invariant constitutive models as well as using experimental data obtained with a viscoelastic
polymer solution and a
polymer melt.
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Materials Science
Hybrid functional calculation of electrical activity and complexing mechanism of Cu-related defects
Xinyu Shi, Zirui He, An-An Sun et al. (+5 more)
Copper is a detrimental
impurity in silicon with high diffusivity and a high tendency to precipitate. Interaction between Cu and other defects is essential for understanding the nature of Cu precipitation in silicon. Despite extensive experimental investigations of Cu-related defects in silicon, a comprehensive understanding remains elusive due to limitations of techniques in resolving defect configurations, as well as inconsistencies between theoretical and experimental results regarding transition levels. Moreover, the underlying formation mechanism of the well-known $\mathrm{Cu_{PL}}$ line is still unclear. In this work, configurations, formation energies, and transition levels of Cu-related defects in silicon are calculated using the HSE06 functional and finite-size correction. Defects involved in this study include $\mathrm{Cu_i}$, $\mathrm{Cu_{Si}}$, Cu-B, Cu-P, and Cu-H. A $\mathrm{Cu_{i4}V}$ model is proposed to explain the discrepancies between theory and experiment about $\mathrm{Cu_{PL}}$ defect. Our calculations may provide insight into the electrically active defects and the early states of Cu precipitation in silicon.
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All authors Xinyu Shi, Zirui He, An-An Sun, Siqing Shen, Yongli Liang, Hao Hu, Shang-Peng Gao, Meng Chen
Materials Science
A unified descriptor framework for hydrogen storage capacity and equilibrium pressure in interstitial hydrides
Seong-Hoon Jang, Di Zhang, Xue Jia et al. (+9 more)
Hydrogen is a promising energy carrier, yet its practical deployment is limited by the lack of storage materials that simultaneously achieve high storage capacity ($w$) and practical
equilibrium pressure at room temperature ($P_{\rm eq,RT}$). Interstitial metal hydrides offer fast kinetics and favorable thermodynamics (high $P_{\rm eq,RT}$) but suffer from intrinsically low w. Here, we establish a physically interpretable, data-driven framework to uncover descriptor-property relationships in interstitial hydrides using a curated database of pressure-composition-temperature measurements (Digital Hydrogen Platform, DigHyd) and white-box symbolic regression. Strikingly, the analysis reveals a clear separation of governing mechanisms, in which $w$ is governed by
geometric and
lattice conditions, captured by the average atomic radius ($\left\langle r_M \right\rangle$) and average thermal conductivity ($\left\langle\kappa\right\rangle$), with an optimal regime of $r_M \sim 1.47 \r{A}$ and relatively low $\left\langle\kappa\right\rangle$. In contrast, $P_{\rm eq,RT}$ is governed by elastic properties, captured by the average shear modulus ($\left\langle G \right\rangle$) and average Poisson's ratio ($\left\langle \nu \right\rangle$), reflecting the role of
lattice rigidity and mechanical compliance. These relationships are translated into compositional optimization pathways that follow the descriptor trends above, enabling the design of candidate materials with enhanced w under practical
equilibrium conditions ($P_{\rm eq,RT} \sim 0.1$ MPa). This work establishes a general, interpretable strategy for physics-informed design of energy materials systems.
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All authors Seong-Hoon Jang, Di Zhang, Xue Jia, Hung Ba Tran, Linda Zhang, Ryuhei Sato, Yusuke Hashimoto, Yusuke Ohashi, Toyoto Sato, Kiyoe Konno, Shin-ichi Orimo, Hao Li
Mesoscale and Nanoscale Physics
Neuromorphic computing with optomechanical oscillators
Andrea Gaspari, Rémi Avriller, Florian Marquardt et al. (+1 more)
The increasing resource demands of artificial neural networks have prompted the exploration of novel platforms better suited for machine learning. In this context, phase oscillators represent a promising candidate due to their intrinsic nonlinearity and their ability to exhibit collective synchronization when coupled together. In the present work, we investigate one such implementation: a network of optomechanical oscillators pumped in the blue-detuned regime to achieve self-sustained oscillations. We propose a theoretical framework to describe their dynamics and demonstrate how such systems can be employed for neuromorphic computing. We discuss how they can be trained and analyze a platform, based on drum resonators, that could enable their physical implementation. Ultimately, the theoretical results obtained from modelling an XOR gate using 5 nodes in an all-to-all configuration are discussed.
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All authors Andrea Gaspari, Rémi Avriller, Florian Marquardt, Fabio Pistolesi
Mesoscale and Nanoscale Physics
Step-Edge Anomaly in Topological Metals
Oskar Schweizer, Virginia Gali, Adam Y. Chaou et al. (+3 more)
Bulk-boundary correspondence guarantees the presence of robust, anomalous states on the boundary of topological matter. The edges of a two-dimensional Chern
insulator harbor one-dimensional
chiral states, which have a conductance $n\, e^2/h$, where $n$ is an integer that is solely determined by the bulk. In this work we show that step edges on the surface of three-dimensional topological metals have a robust conductance $K\, e^2/h$, where $K$ is also fixed by the bulk and assumes non-integer values. We explain this prediction on the basis of the
topology of gapless systems, exemplify it on a
lattice model, and connect to recent experimental observations of enhanced density of states at step-edges in topological metals.
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All authors Oskar Schweizer, Virginia Gali, Adam Y. Chaou, Gal Lemut, Piet W. Brouwer, Maxim Breitkreiz
Disordered Systems and Neural Networks · Cross-listed from quant-ph
Robust quantum metrology using disordered probes
Vishnupriya K., Harikrishnan K. J. and Amit Kumar Pal
Disorder is ubiquitous in
quantum devices including
quantum probes designed and fabricated for
quantum parameter estimation and sensing. We investigate the robustness of a
quantum probe against the presence of glassy disorder. We define a disorder marker quantifying the effect of the disorder by expanding the
quantum Fisher information in terms of different orders of the standardized central moments of the disorder-distributions. We classify the
quantum probes in terms of the possible values of the disorder marker, and analytically show, for a disorder-sensitive probe with identical and weak disorder on all or a subset of the parameters of the probe-
Hamiltonian, that the absolute value of the disorder marker exhibits a quadratic dependence on the disorder strength. We derive a robustness scale intrinsic to the probe that competes with the disorder, and provide a prescription for estimating the maximum disorder strength that the probe can withstand from the disorder-free probe-
Hamiltonian for a given initial state of the probe, which can be computed without the disorder averaging. We demonstrate our results in the case of a single-
qubit probe under disordered
magnetic field, and a multi-
qubit probe described by a disordered one-dimensional Kitaev model with nearest-neighbor interactions.
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Soft Condensed Matter · Cross-listed from physics.flu-dyn
From Sedimentation to Suspension: Critical Strain as a Predictor of Particle Resuspension Thresholds
Mohammadreza Mahmoudian, Simon A. Rogers and Parisa Mirbod
Viscous resuspension, the process by which sedimented particles are re-entrained into a fluid under flow, is central to numerous natural and industrial systems, including environmental contaminant transport, riverbed erosion, and biogeochemical cycling. Despite its ubiquity and importance, predicting when and how resuspension occurs remains challenging, particularly under oscillatory shear, where particle interactions are nonlinear, collective, and time-dependent. Here, we examine the resuspension dynamics of dense, non-Brownian suspensions under both steady and oscillatory shear using bulk rheometry and in situ rheo-microscopy over a broad range of particle volume fractions ({\phi}= 0.30 to 0.55). We demonstrate that strain is the key control parameter governing the transition from a sedimented bed to a fully suspended state. This strain-driven onset is mediated by effective interparticle collisions and collective particle motion. We develop a predictive model that captures the observed strain thresholds as a function of volume fraction, allowing for the construction of a new state diagram delineating sedimentation, resuspension, and full suspension regimes. These findings reveal a robust, strain-controlled resuspension mechanism and establish a unified framework for predicting suspension behavior across steady and oscillatory flows, offering new tools for managing particle-laden transport in geophysical, biological, and industrial environments.
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Strongly Correlated Electrons
Quasi-linear `non-metallic' resistivity in the distorted-kagome metal CrPdAs
Benny Lau, Wenlong Wu, Bo Yuan et al. (+2 more)
We report the growth and characterization of single
crystals of the disorted-kagome
lattice compound CrPdAs.
Spin-glass behaviour with $T_{SG} \sim 60\ {\rm K}$ is observed in all
crystals tested. Some growths show in addition a
magnetic impurity phase with $T_c$ around 200 K, but annealing produces single-phase
crystals without the
ferromagnetic impurity phase. Single-phase
crystals nevertheless have $29\pm 5\%$ anti-site disorder of the Cr and Pd sites, similar to a previous generation of flux-grown polycrystalline samples. We observe a large linear-coefficient of the heat capacity at low temperature, $\gamma = 23 \pm 3$ mJ/mole\,K$^2$, which is typical of kagome metals. The calculated band structure shows several Dirac band-crossings very near $E_F$ whose degeneracy is lifted when
spin-orbit interaction is included. Our most curious finding is a `non-metallic' in-plane resistivity, extending over the entire measured temperature range from 300 K down to 2 K. This resistivity is quasi-linear below about 130 K, and shows no sign of saturation down to the lowest temperature measured.
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All authors Benny Lau, Wenlong Wu, Bo Yuan, Julian Nickel, Stephen Julian
Strongly Correlated Electrons
Role of Excited States in Resonant Charge Transfer during Li$^+$ Backscattering from MoS$_2$: A Multi-Orbital Theoretical Study
Thomas A. Balsamo, Faustino G. Ibarlucea and Marcelo A. Romero
We present a theoretical investigation of resonant charge transfer in low-energy Li$^+$ ions backscattered from a MoS$_2$ surface, focusing on the influence of excited projectile states. Using a time-dependent Anderson model in the infinite-$U$ limit, we evaluate the individual contributions from the Li $2s$, $2p_x$, $2p_y$, and $2p_z$ orbitals to the final charge state distribution. The
Hamiltonian parameters are computed using an expanded Huzinaga basis set that explicitly incorporates lithium's $2p$ orbitals. Each orbital channel is treated separately, and electronic correlation effects are introduced approximately through a probabilistic exclusion principle applied to the final charge state. Theoretical calculations demonstrate that including $2p$ channels enhances the agreement with previously reported experimental neutral fractions, where the single-channel descriptions show noticeable discrepancies. Among excited states, the $2p_z$ orbital oriented perpendicular to the surface contributes most significantly due to its spatial extension toward the substrate. Examination of temporal
evolution reveals that independent channel occupations exceed unity at small projectile$-$surface separations, highlighting the necessity of dynamical correlation treatments. These findings establish that excited states make non-negligible contributions to charge exchange processes for alkali ions interacting with transition metal dichalcogenide surfaces and should be incorporated for accurate quantitative modeling.
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Statistical Mechanics
The Widom line in the Ising model on a decorated bilayer lattice
Joseph Chapman, Justas Gidziunas, Bruno Tomasello et al. (+1 more)
There has been much recent interest devoted to a class of frustrated one-dimensional statistical mechanics
lattice models which exhibit sharp thermodynamics. In this work, we study an extension of one of these models to two dimensions; the Ising model on a decorated
bilayer lattice. We show that the pseudo-transitions of the one-dimensional models become a real first order phase transition in this two-dimensional analogue. Moreover, the pseudo-transition is found to still exist above a bi-critical point. This can be characterised as a Widom line, which allows a re-interpretation of the physics in the previously studied one-dimensional models.
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All authors Joseph Chapman, Justas Gidziunas, Bruno Tomasello, Sam Carr
Quantum Gases
Morphological false-vacuum decay in dipolar supersolids
Wyatt Kirkby, Lauriane Chomaz and Thomas Gasenzer
False-
vacuum decay between two morphologically distinct supersolid phases via bubble nucleation is studied in a uniform dipolar gas confined to the plane. Starting from a metastable honeycomb state, the formation of stripe phase domains is simulated numerically by means of a
stochastic projected extended Gross-Pitaevskii equation. The speed of bubble growth is analyzed in relation to the multiple speeds of sound of the supersolid, and is found to be set by the slowest of these sounds. The
vacuum decay rate is numerically extracted and compared against a minimal effective model for the Coleman bounce solution connecting the two supersolid orders. Our results establish dipolar supersolids as a novel and versatile platform for studying false-
vacuum decay. This setting offers a rich structure of metastable states and collective excitations that come into play in the decay. Furthermore, here, in contrast to previous studies, bubble formation occurs directly in the real-space density and can be probed with in situ imaging.
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Mesoscale and Nanoscale Physics
Loop-dependent entangling holonomies in localized topological quartets
Kazuki Ikeda and Yaron Oz
A spectrally isolated quartet can admit a local two-
qubit description at each point in parameter space and still acquire a loop holonomy outside the local subgroup $\mathrm{U}(2)\otimes\mathrm{U}(2)$. We study this question in three localized topological settings, a BHZ ribbon, a spinful SSH chain, and a BBH corner quartet. On a fixed quartet, changing only the loop can move the holonomy from almost local to entangling. In BHZ, co-rotating and counter-rotating edge-field loops have nearly the same eigenphase data, but only the counter-rotating loop yields an Ising-like entangler. SSH gives a controlled-rotation example in a numerically stable edge quartet. BBH shows the same issue in a higher-order corner quartet. Standard Berry data, including Berry phases, Chern numbers, determinant phases, and eigenphase spectra, do not separate these cases. The main diagnostic is the distance from the loop holonomy to the extracted local subgroup. Canonical two-
qubit coordinates are used only after reduction failure has been identified. The quartet is the smallest setting in which this question can be tested explicitly. The same subgroup-reduction problem extends to any isolated multiplet with pointwise product type $D=\prod_{\alpha}d_\alpha$, where the relevant local subgroup is the embedded product group $G_{\mathbf d}=\mathrm{Im}[\prod_{\alpha}U(d_\alpha)\to U(D)]$. In the terminology of Ref.[arXiv:2601.13764], these examples realize loop-dependent entangling gluing.
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Materials Science
Pt-wedge squeegee cleaning of two-dimensional materials and heterostructures
Emine Yegin, Doruk Pehlivanoğlu and T. Serkan Kas{\i}rga
The surface of ultra-thin materials plays a crucial role in determining the properties. This is particularly important in two-dimensional (2D) materials where the surface-bulk distinction is no longer present. While mechanical cleaning of two-dimensional materials to remove interfacial and surface contaminants is used to achieve better sample quality, low throughput and the challenging optimization of cleaning procedures hinder their widespread adoption. Here, we report on atomic force microscope (AFM)-based mechanical cleaning with modified AFM cantilevers for high-throughput and easy-to-implement cleaning of 2D materials and their
heterostructures. A Pt-wedge is deposited via focused ion beam on the cantilever to improve the mechanical cleaning of samples and streamline the cleaning procedures. We demonstrate that a cleaning rate of 3 {\mu}^2/s can be achieved with our modified cantilevers, compared to the 0.01 {\mu}^2/s effective cleaning rate in pointy-tip cleaning. As showcases, we demonstrate that monolayer WS2 on h-BN exhibits much sharper photoluminescence (PL) emission at room temperature after AFM cleaning, and WS2 monolayers exhibit a higher quality contacts to cleaned Au electrodes as compared to uncleaned electrodes. We also showed that h-BN encapsulated
heterostructures can be cleaned rapidly using the improved method. Overall, our results exhibit a feasible and facile path for the large-scale application of AFM-based cleaning of integrated 2D materials.
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Materials Science
Berry curvature and field-induced intrinsic anomalous Hall effect in an antiferromagnet FeTe
Satoshi Okamoto, Adriana Moreo, Naoto Nagaosa et al. (+1 more)
Berry
curvature is ubiquitous in condensed matter physics and materials science. Its main consequence is the intrinsic anomalous
Hall effect (AHE) in
magnetic materials and plays a pivotal role in spintronic applications and
quantum technologies. Here, we present a theoretical study of the intrinsic AHE in tetragonal FeTe, a semimetallic van der Waals antiferromagnet with compensated
magnetic ordering at low temperatures. Using a realistic
spin-
fermion model, we demonstrate that FeTe exhibits a large Berry-
curvature-driven AHE under an applied
magnetic field. Our calculations reveal that the
Hall conductivity of this compound is extremely sensitive to temperature and field strength and even exhibits sign reversal, highlighting FeTe as a prototypical platform where magnetism and
topology combine to produce robust intrinsic
Hall responses. This work establishes FeTe as a promising candidate for exploring
quantum transport in low-dimensional correlated systems. We also discuss the implications for recent experimental results of the AHE and ordinary
Hall effect reported for FeTe.
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All authors Satoshi Okamoto, Adriana Moreo, Naoto Nagaosa, Stuart S. P. Parkin
Statistical Mechanics · Cross-listed from cs.CL
Phonological distances for linguistic typology and the origin of Indo-European languages
Marius Mavridis, Juan De Gregorio, Raul Toral et al. (+1 more)
We show that short-range phoneme dependencies encode large-scale patterns of linguistic relatedness, with direct implications for quantitative typology and evolutionary linguistics. Specifically, using an information-theoretic framework, we argue that phoneme sequences modeled as second-order Markov chains essentially capture the statistical correlations of a phonological system. This finding enables us to quantify distances among 67 modern
languages from a
multilingual parallel corpus employing a distance metric that incorporates articulatory features of phonemes. The resulting phonological distance
matrix recovers major
language families and reveals signatures of contact-induced convergence. Remarkably, we obtain a clear correlation with geographic distance, allowing us to constrain a plausible homeland region for the Indo-European family, consistent with the Steppe hypothesis.
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All authors Marius Mavridis, Juan De Gregorio, Raul Toral, David Sanchez