Materials Science
A Hybrid Quantum Mechanics Machine Learning Forcefield (QM/ML) Framework for Accurate Solute-Dislocation Interaction Simulations
Junting Zhang, Colleen Reynolds, Ryan S. Stroud et al. (+4 more)
Solute-dislocation interactions play a central role in controlling microstructural
evolution and mechanical behaviour of structural materials, yet conventional atomistic modelling approaches struggle to combine the chemical accuracy with computational scalability. In the
nuclear industry, these challenges become particularly acute, as experiments reveal strong correlations between solute segregation and irradiation-induced dislocation loops. However, theoretical insight remains limited because density functional theory (DFT) simulations are prohibitively expensive at relevant length scales, while traditional semi-empirical interatomic potentials lack the chemical fidelity required for predictive solute-defect calculations. Here, we introduce a hybrid
quantum-mechanics/machine-learning (QM/ML) simulation framework that couples DFT with neural-network machine learning interatomic potentials (MLIPs), enabling accurate atomistic dislocation simulations at reduced computational cost. We demonstrate the QM/ML framework's capability by reproducing the experimentally observed Sn and Fe segregation to dislocation loops in Zr and investigating magnetically complex solute-dislocation interactions in steel. These results establish the approach as a transferable, high-fidelity tool for modelling irradiation-induced defect structures and benchmarking emerging MLIPs.
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All authors Junting Zhang, Colleen Reynolds, Ryan S. Stroud, Jana Smutna, Daniel J. M. King, Andrew P. Horsfield, Mark R. Wenman
Materials Science
Giant and Broadband Circular Dichroism from Particle-Hole Symmetry Breaking in Weyl Semimetals
Xiangyu Jiang, Zeping Shi, Yuhan Du et al. (+14 more)
Circular dichroism originates from
symmetry breaking of material structure, leading to differential absorption of left- and right-circularly polarized light. However, circular dichroism in most materials is inherently weak and spectrally narrow, especially in the mid-to-far infrared. Here, we uncover
giant infrared circular dichroism in the
magnetic-field-forced Weyl semimetal Mn(Bi,Sb)2Te4, driven by extreme particle-hole
symmetry breaking. Helicity-resolved magneto-infrared spectroscopy reveals circular dichroism exceeding 3000 mdeg (~130 mdeg/nm) with above-degree response extending over the 6-13 {\mu}m spectral range. The optical resonances are enhanced by a strong band nesting effect intrinsic to the Landau levels of type-II Weyl dispersion. A
symmetry-based kp model reproduces these magneto-infrared responses and demonstrates that magnetization-induced asymmetric
spin-orbit coupling generates particle-hole
symmetry breaking, suppressing
spin-up, parity-even wavefunction components in the valence Landau band and thereby producing pronounced optical helicity selectivity. Our findings establish particle-hole
symmetry breaking as an effective route toward helicity-resolved optical control in
quantum materials.
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All authors Xiangyu Jiang, Zeping Shi, Yuhan Du, Haonan Chen, Jiayu Wang, Wenbin Wu, Guangyi Wang, Congming Hao, Mingfan Yao, Mingsen Zhou, Xin Chen, Chenyao Xu, Zhongbo Yan, Cheng Zhang, Hai-Zhou Lu, Junhao Chu, Xiang Yuan
Materials Science
Hydrogen segregation around a straight screw dislocation in bcc iron
Margot Lucas, Marie Landeiro Dos Reis, Sylvain Queyreau et al. (+1 more)
The interaction between hydrogen and screw dislocations in bcc iron is central to understanding hydrogen embrittlement. A major challenge lies in the high-dimensional parametric landscape governing this interaction. In this work, we perform a comprehensive set of molecular simulations using a reliable neural network interatomic potential, systematically exploring hydrogen binding across dislocation core structures (easy and hard cores), site types, and concentrations. From these energetics, we construct a thermodynamic framework that quantifies the statistical relevance of the various trapping configurations, thereby significantly reducing the complexity of the problem. Our results show good agreement with the limited density functional theory data available in the literature. We further delineate the validity domain of an elastic dipole description of hydrogen-dislocation interactions, providing a simplified yet physically grounded modeling approach. Finally, we demonstrate that the easy-core configuration plays a key role in rationalizing experimental hydrogen solubility limits. These findings establish a consistent multiscale foundation for incorporating hydrogen-dislocation interactions into larger-scale models of plasticity and embrittlement.
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All authors Margot Lucas, Marie Landeiro Dos Reis, Sylvain Queyreau, Xavier Feaugas
Materials Science
Controlled chemical vapor deposition for synthesis of emerging Mo(W)Te2 systems
Ya Deng, Zi-Yi Han, Yao Wu et al. (+6 more)
The Group-VI transition metal ditellurides offer a rich platform for correlated and topological phenomena, yet their structural polymorphism and instability complicate the creation of single
crystals and heterointerfaces. Here, we introduce a confined-space chemical vapor deposition (CVD) strategy that lowers the growth temperature window and, when combined with tailored precursor configurations and stepwise thermal ramps, enables the deterministic synthesis of high-quality single
crystals,
alloys, and lateral/vertical
heterostructures. High-resolution aberration-corrected STEM provides atomic characterization of
lattice-matched Mo(W)Te2 lateral
heterostructure, revealing nearly atomically sharp, compositionally well-defined seamless boundaries. This approach avoids the thickness nonuniformity and structural limitations commonly associated with exfoliated samples, enabling reproducible fabrication of clean heterointerfaces and establishing a nearly ideal in-situ experimental system. Furthermore, scanning tunneling microscopy and spectroscopy (STM and STS) enable direct imaging of the seamless boundaries in Mo(W)Te2 lateral
heterostructures, while uncovering their distinct real-space distributions of the local density of states. Our results establish a scalable pathway for engineering crystalline Te-based structures with controlled geometry and stacking, providing an essential step toward
quantum and topological device platforms based on the transition metal ditellurides family.
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All authors Ya Deng, Zi-Yi Han, Yao Wu, Kongyang Yi, Ya-Ning Ren, Dundong Yuan, Chao Zhu, Lin He, Zheng Liu
Statistical Mechanics · Cross-listed from cs.IT
Grouped Reverse Importance Sampling for the Partition Function
Neri Merhav
We introduce and analyze several grouped variants of the method of reverse importance sampling (RIS) for estimating a partition function from samples of the Boltzmann distribution $p(x)=e^{ \betaU(x)}/Z(\beta)$. Ordinary RIS weighs each sample separately. By contrast, our proposed grouped RIS (GRIS) methods are based on assigning the samples into groups (or batches) of size $k\ge 2$ and applying a joint weight function to each group. The focal point of the research is the quest for a tractable weight function that would yield the smallest possible mean squared error (MSE). A simple identity relates the normalized MSE to the chi-squared divergence between the joint-weight distribution and the distribution of the $k$-fold sum of independent energies. Our first theoretical finding is that any weight that improves on ordinary RIS ($k=1$) must couple the group components. In other words, it must not be a product-form function across those components, as product-form weight functions always worsen the MSE. Our second, and more important, finding is that, without loss of optimality, it is sufficient to seek weight functions that depend only on the total energy, $\sum_iU(x_i)$, of the group (group-energy weight functions); for the sliding-window variants, the analogous result is open. This finding simplifies both the theoretical analysis and the application of the method substantially. For $k=2$ and $k=3$, the MSE associated with non-overlapping (NOL) groups is reduced by $20$–$65\%$ across three examples. We then propose two additional variants of GRIS, both based on sliding-window grouping (as opposed to NOL grouping). The first applies a fixed weight sliding window (FSW) across all (cyclic) shifts of the sliding window, and the second allows a variable-weight sliding window (VSW). The FSW scheme improves on the NOL one, and the VSW improves even further, as will be demonstrated numerically.
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Soft Condensed Matter
Solid-to-solid transition in dense assemblies of elongated cells
Shao-Zhen Lin and Jean-François Rupprecht
Cell shapes in confluent tissues range from nearly isotropic epithelial morphologies to highly elongated endothelial ones. In standard vertex models, tissue
rigidity is controlled by a target shape index; increasing this index drives
cell elongation and ultimate tissue fluidization. Here, we consider the case where
cell elongation emerges autonomously by assigning an intrinsic, passive elastic preference for anisotropic shape. This distinction reverses the usual expectation:
cell elongation does not fluidize the tissue, but drives a solid-to-solid transition from an ordered isotropic solid to a disordered anisotropic solid, with finite yield stress and shear
rigidity on either side of the transition. These results decouple
cell shape from tissue rheology and caution against inferring fluid-like mechanics from elongated
cell morphologies alone.
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Mesoscale and Nanoscale Physics
Perfect Absorption in the Strong Coupling Regime via Degenerate Critical Coupling
Eleonora P. Kraus, Jamie M. Fitzgerald, Carlos Maciel-Escudero et al. (+1 more)
Perfect absorption (PA) represents a fundamental limit of light-matter interaction and a means to maximize nanoscale energy conversion. While PA is now a well-established phenomenon, both the theoretical feasibility and a practical mechanism for achieving it under single-beam excitation within the strong coupling regime is unknown. Through rigorous solution of Maxwells equations for a compact photonic
crystal (PhC) architecture incorporating a two-dimensional
semiconductor, we present a general method based on degenerate critical coupling for single-port PA of
exciton-polaritons. At the crossing of two polariton branches, we achieve near-unity absorption exceeding 99.8 % in a structure thinner than $100\,$nm. This effect is robust under realistic Gaussian beam excitation, and can be realized across different temperatures and excitonic materials by tailoring the PhC geometry. Our results establish a strategy for enabling efficient light-matter coupling, with direct implications for the development of metal-free, ultra-compact polaritonic logic devices, sensors, and energy-harvesting platforms.
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All authors Eleonora P. Kraus, Jamie M. Fitzgerald, Carlos Maciel-Escudero, Ermin Malic
Materials Science
Thermal Rectification from Size-Dependent Phonon Confinement in Nanoparticle Assemblies
Megan J. Farrington, David J. Wasserman, Eden R. Josza et al. (+6 more)
Thermal insulation remains an important technological challenge across the vast number of applications, from living quarters to
quantum technology. Here, we exploit the size-dependent modification of the
phonon density of states arising from
phonon confinement in nanoparticles to fabricate a simple
phonon rectifier. The smaller of the two connected nanoparticles imposes stronger
phonon confinement leading to rectifying
phonon transport. This concept is extended to the macroscale by constructing two overlapping layers of differently sized nanoparticles, thereby realizing a macroscopic
phonon diode. Following the localized heat deposition by
laser light, the temperature profiles across a
phonon-diode were measured by infrared imaging. Although the rectifying strength is moderate, the abundance of optimization possibilities makes this method promising for ultra-low volume thermal insulation at both the nano- and macroscale
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All authors Megan J. Farrington, David J. Wasserman, Eden R. Josza, Alessandro Podestà, Alessio Zaccone, Mariia Sidorova, Alexej D. Semenov, Nicola Ludwig, Marcel Di Vece
Materials Science
Preconditioning Magnetic Systems in Kohn-Sham Density Functional Theory
Clémentine Barat, Antoine Levitt and Marc Torrent
The convergence of the self-consistent field iterations in Kohn-Sham density functional theory can be significantly hindered by the presence of small
eigenvalues in the dielectric
matrix, which are often associated with electronic phase transitions in
magnetic systems. In this work, we study this type of convergence issues and propose a new preconditioning scheme to mitigate them. Our preconditioning scheme is inspired by the Stoner model and based on a non-interacting susceptibility that neglects orbital variations. We demonstrate the effectiveness of our approach on a range of
ferromagnetic systems, showing that it can significantly reduce the number of iterations required to achieve convergence in the vicinity of
magnetic phase transitions.
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Mesoscale and Nanoscale Physics
Floquet Topological Phases and Anomalous Hall Signatures in Irradiated Two-dimensional $d_{xy}$-Wave Altermagnets
Hosein Cheraghchi
We study Floquet topological phases in two-dimensional $d_{xy}$-wave altermagnets driven by off-resonant circularly polarized light and subject to an out-of-plane magnetization induced via extrinsic exchange coupling from a proximate ferromagnet. Using a
lattice Floquet formulation, we show that the system is governed by a driving parameter $\beta$ that controls the emergence of distinct gap-closing points and associated topological phases. For $|\beta|>1$,
topology is dominated by anisotropic Dirac points at high
symmetry points, leading to Chern phases with $|\mathcal{C}|=2$. For $|\beta|<1$, light-induced off-
symmetry $G$ points appear in four families in the Brillouine zone, enabling higher Chern phases up to $|\mathcal{C}|=4$. Low-energy analysis reveals that high
symmetry points host anisotropic massive Dirac
fermions, while $G$ points realize generalized two-dimensional anisotropic Dirac points with fully momentum-dependent pseudospin structure, leading to distinct Berry
curvature distributions. In the metallic regime, the anomalous
Hall conductivity provides an experimental signature of these Floquet topological phases, exhibiting sharp features associated with Berry
curvature accumulation near local gap-closing regions.
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Soft Condensed Matter
Analyzing the Gelation Transition through Fractional Viscoelasticity and the Mittag-Leffler-Prabhakar Function
Yogesh M Joshi
The gelation transition, a process that transforms a flowable
liquid into an elastic solid, occurs in a variety of systems, ranging from colloidal to polymeric. During the gelation transition, a system passes through a critical gel state characterized by scale-free power-law viscoelasticity. Interestingly, the fractional calculus provides a natural mathematical
language for such power-law viscoelasticity. In this work, we develop physically constrained fractional viscoelastic models, as well as those based on the three-parameter Mittag-Leffler-Prabhakar function, for both the pre-gel and post-gel regimes, ensuring consistency with the conventional scaling relations in each regime. While the fractional pre-gel model is observed to be valid only for a restricted subset of parameter values, the Prabhakar function-based model for the relaxation modulus, which translates into a Havriliak-Negami function-based complex modulus, rigorously removes this limitation. We enforce continuity of the dynamic
moduli and their derivatives across the critical gel point, which universally imposes a
symmetry in the relaxation dynamics on either side of the critical gel state. Such enforcement further validates the hyperscaling relation connecting the critical exponents, making it a theoretical necessity rather than an empirical coincidence. We validate the proposed models against time- and frequency-domain experimental data. A model-agnostic, frequency-independent rheological fingerprint of the critical gel state, uniquely determined by two critical exponents, is also identified.
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Soft Condensed Matter
Solid adsorption: the missing mechanism for surfactant contact lines – a phase-field approach
Parvathy K. Kannan, Kazi T. Iqbal, Diego Díaz et al. (+5 more)
We develop a thermodynamically consistent phase-field model for soluble surfactants in two-phase flows, incorporating both interfacial and solid surface adsorption. The model is derived via variational principles consistent with the second law of thermodynamics, resulting in modified free energies and boundary conditions that capture surfactant transport, adsorption, and wetting dynamics. A key contribution of this work is the inclusion of surfactant adsorption on solid walls, which leads to qualitative agreement with experimental observations: unlike prior numerical studies that predicted hydrophilic surfaces becoming more hydrophilic and hydrophobic surfaces more hydrophobic, our model shows a shift toward increased hydrophilicity across all contact angles-consistent with experimental trends. Our results establish that solid adsorption provides the missing mechanism required for predictive modelling of surfactant-laden contact line dynamics.
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All authors Parvathy K. Kannan, Kazi T. Iqbal, Diego Díaz, Ilse Mateman, Shahab Mirjalili, Gustav Amberg, Shervin Bagheri, Outi Tammisola
Soft Condensed Matter
Dynamic heterogeneity in sodium silicate melts via machine-learning potential
Kumpei Shiraishi, Rikuta Nozawa and Emi Minamitani
We present a comprehensive characterisation of dynamic heterogeneity in sodium silicate melts using molecular dynamics simulation with machine-learning potentials. By studying sodium disilicate, tetrasilicate, and hexasilicate melts across a range of temperatures, mean squared displacement and a time-correlation function computed up to the nanosecond timescale provide a detailed account of how spatial mobility disparities emerge in a realistic multicomponent
oxide glass. Within these timescales, the self-part of the van Hove function for sodium displays a bimodality, demonstrating that alkali transport is mediated by discrete displacement events consistent with a hopping mechanism. This distinct hopping allows sodium ions to decouple from the sluggish relaxation of the silicate
matrix. Furthermore, evaluation of the non-Gaussian parameter reveals that, although all constituent species exhibit dynamic heterogeneity, the non-Gaussian behaviour is most pronounced for oxygen atoms. This trend reflects the intermittency of structural rearrangements, where framework atoms undergo rare and
stochastic events compared to the frequent displacements of mobile ions. Our findings elucidate the microscopic mechanism of ion transport and its connection to dynamic heterogeneity in silicate melts, offering a new avenue to study fundamental glassy physics in realistic vitreous materials.
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Materials Science
Lattice Reconstruction and Orbital Hybridization Suppress Magnetism in TaCo$_2$Te$_2$
Ulysse Chazarin, Bharat C. Bathu, Zuned Ahmed et al. (+6 more)
Structural reconstruction in low-dimensional
quantum materials can strongly modify electronic
symmetry and
magnetic stability through orbital hybridization. Here, we investigate the interplay between
lattice reconstruction, electronic structure, and
magnetic instability in the layered van der Waals compound TaCo$_2$Te$_2$ using scanning tunneling microscopy and spectroscopy (STM/STS), non-contact atomic force microscopy (nc-AFM), angle-resolved photoemission spectroscopy (ARPES), and density functional theory (DFT). While nc-AFM resolves a distorted hexagonal Te surface
lattice, STM/STS reveal a pronounced square-like electronic
symmetry that does not directly follow the atomic structure. ARPES further shows a strongly anisotropic
Fermi surface and reconstructed low-energy states. Spatially resolved spectroscopy and orbital-projected DFT demonstrate that the bias-dependent STM contrast does not arise from a simple reversal between occupied and unoccupied states, but from the energy-integrated local density of states dominated by electronic states exhibiting opposite spatial contrast at selected energies. DFT calculations further show that reconstruction suppresses the
magnetic instability present in the undistorted structure, stabilizing a nonmagnetic ground state through enhanced orbital hybridization. These results establish TaCo$_2$Te$_2$ as a model system in which
lattice reconstruction reorganizes electronic
symmetry and suppresses magnetism, highlighting structural reconstruction as a route for controlling correlated and
magnetic phases in low-dimensional
quantum materials.
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All authors Ulysse Chazarin, Bharat C. Bathu, Zuned Ahmed, Marta Zonno, Chiara Bigi, Francois Bertran, Adolfo O. Fumega, Orlando J. Silveira, Shawulienu Kezilebieke
Mesoscale and Nanoscale Physics
Floquet-Engineered Chern Insulator in two-dimensional $d_{x^2-y^2}$-Wave Altermagnets
Hosein Cheraghchi
We investigate Floquet-engineered topological phases in two-dimensional $d_{x^2-y^2}$-wave altermagnets irradiated by circularly polarized light in the off-resonant regime. These materials exhibit large momentum-dependent
spin-splitting governed by distinctive
magnetic symmetries. Using a
lattice model combined with Floquet theory, we demonstrate that irradiation induces the light-tunable
quantum anomalous
Hall phases with the Chern numbers up to $\pm 3$. The resultant phase diagram is verified by calculating the anomalous
Hall conductivity and also the edge modes inside the band gap of a nanoribbon version of the altermagnet. Our findings establish d-wave altermagnets as promising platforms for realizing nonequilibrium topological states of matter. The low-energy continuum limit of the
lattice-based Floquet
Hamiltonian results in a linear and higher-order-in-momentum
spin-orbit couplings, and also a Zeeman-like magnetization, all arising from light-induced virtual
photon processes. The resulting higher-order
spin-orbit coupling generates the additional gapless Dirac points which, together with the high-
symmetry gap-closings, yield enhanced Berry
curvature and high Chern numbers. The light irradiation effectively breaks the static $d_{x^2-y^2}$-wave
magnetic symmetry mixing in an isotropic photo-induced $s$-wave correction.
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Strongly Correlated Electrons · Cross-listed from hep-th
Central charges $C_J$ and $C_T$ in QED$_d$-GNY model and scalar QED$_d$
Yongwei Guo and Zhijin Li
We compute the leading-order $1/N$ corrections to the central charges $C_J$ and $C_T$ in the conformal QED$_d$-Gross-Neveu-Yukawa (GNY) model and the scalar QED$_d$ in $d$ dimensions. The scaling dimensions of the lowest adjoint bilinear scalars are obtained to order $O(1/N)$ for general $d$. In $d=3$, the $U(1)$ Abelian gauge theory possesses a topological $U(1)$ global
symmetry, and we evaluate the central charge $C_J^{\text{top}}$ of the topological
symmetry current to subleading order in the $1/N$ expansion. Our interest in these theories is primarily motivated by their potential connection to the $SO(5)$ symmetric deconfined
quantum critical point (DQCP). We compare the large $N$ results for the central charges $C_J$ and $C_T$ with the conformal data of the $SO(5)$ DQCP obtained from fuzzy sphere and conformal bootstrap. The large $N$ predictions of the QED$_3$-GNY model are found to be in reasonable agreement with the nonperturbative estimates for the $SO(5)$ DQCP.
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Mesoscale and Nanoscale Physics
Photon-Assisted Tunneling in Double Quantum Dot: Application of Scattering Theory
Miyu Umebayashi and Mikio Eto
We theoretically examine the
photon-assisted tunneling (PAT) in a double
quantum dot (DQD) in parallel when one of the
quantum dots (QDs) is irradiated by an AC field. First, we formulate the PAT in a single QD by solving the time-dependent Schrödinger equation using the scattering theory. The QD has an oscillating energy level, $\varepsilon(t)=\varepsilon_0+eV_{\mathrm{AC}}\cos\omega t$, and is connected to two leads by the tunnel coupling $\Gamma$. We show that the resonant tunneling takes place through energy levels of the polariton, $\varepsilon_0+N\hbar\omega$ ($N=0,\pm 1, \pm 2, \cdots$), when $\Gamma \ll \hbar\omega$ (PAT) and through the energy level $\varepsilon(t)$ when $\Gamma \gg \hbar\omega$ (adiabatic transport). Then, the scattering theory is applied to the PAT in the DQD in the presence of
magnetic flux penetrating between the QDs. We observe the Aharonov–Bohm effect not only in the main peak ($N=0$) but also in subpeaks ($N \ne 0$), indicating coherent transport through the polariton states. Our theory is also applicable to the DQD in the three-terminal geometry. We demonstrate the phase measurement through the irradiated QD and show that the measured phase shift changes continuously from 0 to $\pi$ around both the main peak and subpeaks.
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Quantum Gases
Binary Dipolar Condensates of Dysprosium Isotopes with Tunable Spatial Order
Shenshuang Nie, Zibin Jiang, Junrong Huang et al. (+4 more)
Dipolar
quantum mixtures provide a route to many-body phases in which long-range anisotropic interactions couple with density, composition and spatial order. Here we realize a new
quantum-degenerate dipolar mixture of $^{162}$Dy and $^{164}$Dy in a single-species-like apparatus. The mixture combines nearly matched single-particle
Hamiltonians, tunable interactions and composition parameters, and isotope-resolved characterization. Tuning the interaction balance and relative composition reorganizes the coupled condensates from a miscible state into core–shell-like, side-by-side, and exchanged core–shell-like immiscible configurations. These results establish dysprosium isotope mixtures as a compact and versatile platform for multicomponent dipolar
quantum matter, ranging from
impurity physics to binary supersolidity.
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All authors Shenshuang Nie, Zibin Jiang, Junrong Huang, Xiao Luo, Fucheng Qin, Kaiyue Wang, Mingyang Guo
Materials Science
Shape-Constrained Bayesian Active Learning of Self-Limiting Saturation Curves
Pouyan Navabi and Christos G. Takoudis
Saturation curves, monotone responses that rise from zero to a plateau, recur across gas adsorption, enzyme kinetics, and self-limiting growth. Learning one from a few costly, noisy measurements is a common bottleneck. We present a
Bayesian active-learning platform built on a penalized monotone I-spline. Non-negative weights make every posterior draw rise from zero and never fall, a survey measurement anchors the plateau in place of a flatness prior, and the input reaching any saturation level is read from the posterior by level crossing, assuming no kinetic form. Each measurement is placed where the surrogate is least certain, which beats random designs and edges a log-spaced grid of the same budget. One fixed configuration recovers five kinetically distinct regimes from twenty measurements to a saturation error of 0.037 to 0.041, below the output noise, and averages 0.045 on 250 curves from an unseen distribution. Running unconstrained Gaussian processes (GPs) and two unpenalized monotone bases through the same loop separates each ingredient's contribution. Logarithmic resolution and the roughness penalty carry the accuracy, while monotonicity guarantees a level crossing unique on every draw. The penalty keeps the surrogate the most accurate model at every noise level, and its second-order form centers the recommended input for saturation where a first-order penalty reads late (a bias of +0.32 s with 94% coverage, against +0.44 s and 64% for the matched unconstrained GP). Because the recommended input lies where the curve is nearly flat, no method can pin it down precisely, and we report it as a cost-indexed
quantile with the probability of falling short.
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Materials Science
Topological phase transition driven by in-plane spin rotation
Xinyue Zhu, Yu Xie, Yifei Hao et al. (+3 more)
The intrinsic coupling between magnetism and nontrivial band
topology in
magnetic topological
insulators makes external
magnetic fields a powerful tool for manipulating topological states. However, conventional
magnetic control mechanisms, such as driving
magnetic phase transitions or fully reversing magnetization, typically demand large
magnetic fields and lack continuous tunability. Here, we establish a
symmetry framework for the reversible switching of topological states via continuous in-plane
spin rotation, governed by
magnetic point group constraints on the Berry
curvature distribution. Using a two-dimensional kagome
ferromagnetic Chern
insulator as a prototype, we demonstrate that a 60{\deg}in-plane magnetization rotation reverses the sign of the Chern number, transitioning through a topologically trivial state. Crucially, micromagnetic simulations confirm that this
spin-reorientation-driven switching operates under exceptionally small
magnetic fields and on ultrafast timescales. This work provides a highly efficient, low-energy paradigm for the manipulation of topological states.
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All authors Xinyue Zhu, Yu Xie, Yifei Hao, Fei Gao, Yue Li, Junting Zhang
Statistical Mechanics · Cross-listed from nlin.SI
Symmetries of the Generalized Yang–Baxter Equations
Pramod Padmanabhan, Somnath Maity, Akash Sinha et al. (+1 more)
The generalized Yang-Baxter equations are multi-site versions of the standard Yang-Baxter equation. When spectral parameters are included, such equations are expected to lead to integrable
Hamiltonians with local interactions involving multiple degrees of freedom. In this work we characterize both the continuous and discrete
symmetries of these equations required to establish an equivalence class of solutions. We find that the set of such
symmetries depends on the number of sites on which the equation is supported. In several cases there are more
symmetries than the standard Yang-Baxter equation, thus placing heavy constraints on the number of inequivalent solutions and the associated integrable models. As an application we show how to restrict the generic $16\times16$ ansatz to the 30-dimensional subspace invariant under a chosen discrete
symmetry subgroup. An explicit $16\times 16$ solution is also written down.
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All authors Pramod Padmanabhan, Somnath Maity, Akash Sinha, Vladimir Korepin
Materials Science
Ductility Design Rules for Tungsten based Refractory High Entropy Alloys from Sparse Experimental Datasets
Avik Mahata and Nick Beaver
Tungsten-based refractory high-
entropy alloys (RHEAs) are promising materials for fusion applications but often remain brittle at room temperature because of tungsten's high ductile-to-brittle transition temperature (DBTT). To identify alloying strategies that improve ductility, we compiled a curated
dataset of experimentally reported tungsten-containing
alloys and developed composition-based, physics-informed descriptors for machine learning. Three classifiers were evaluated using nested cross-validation, and a support vector classifier (SVC) showed the best generalization for this sparse
dataset. Shapley additive explanations identified the exchange-correlation parameter, valence electron concentration, pressure field, and electronegativity mismatch as the most influential features governing ductile-brittle behavior. Synthetic compositions generated within the convex interpolation domain of the training data were evaluated and visualized on pseudo-ternary diagrams to map predicted ductility trends. The model predicts that moderate additions of Ti, Ni, and Co increase the likelihood of room-temperature ductility, whereas high Cr contents promote brittle behavior. These predictions agree with published experimental observations, including Ti-assisted ductility through solid-solution and electronic effects and embrittlement in Cr-rich refractory
alloys. Agreement between DFT-derived elastic descriptors and SVC decision-function margins further supports the physical relevance of the learned classification boundary. Although the available mechanical
dataset remains limited and heterogeneous, the model captures experimentally consistent trends and provides an interpretable, physics-informed framework for screening tungsten-based RHEAs for targeted simulation and experimental validation in fusion environments.
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Mesoscale and Nanoscale Physics
Photo-thermal origin of pulse laser induced orientation of crystallographic c axis in Tellurium thin films
Arata Mitsuzuka, Yuta Kobayashi, Takuto Hiraoka et al. (+2 more)
Recent studies have shown that the orientation of crystallographic c axis of Tellurium thin films can be controlled using picosecond long
laser pulses. This method provides spatially programmable control of the
crystal orientation and is therefore highly attractive for practical applications in functional optical and electronic devices. Previously, it was suggested that
laser-induced selective melting and recrystallization can cause the
laser-induced reorientation. However, this interpretation remains inconclusive due to limited data. To clarify the mechanism, here we systematically study Te samples under different irradiation conditions. We find that the threshold fluence for inducing optical reorientation depends on the number of
laser pulses. The results agrees well with a minimal kinetic model based on the Arrhenius law. Using the model developed, we investigate the condition required to control the optic axis in other two-dimensional materials, such as black phosphorus, WTe2, and SnSe. These findings provide a guide for developing functional electro-optical devices based on anisotropic materials.
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All authors Arata Mitsuzuka, Yuta Kobayashi, Takuto Hiraoka, Masashi Kawaguchi, Masamitsu Hayashi
Soft Condensed Matter · Cross-listed from astro-ph.EP
A semi-analytic model of the bouncing barrier for protoplanetary dust aggregates
Sota Arakawa, Haruto Oshiro, Yuki Yoshida et al. (+1 more)
Collisional bouncing limits the growth of
dust aggregates in protoplanetary disks, but its dependence on aggregate size, collision velocity, and filling factor remains poorly understood. Here we develop a semi-analytic model for the sticking probability of colliding
dust aggregates. We divide each aggregate collision into two phases: a compression phase and a separation phase. The compression phase is described with an elastoplastic contact model, which determines the maximum contact radius and repulsive energy after compression. The separation phase is treated as fracture of a
stochastic network of interparticle bonds, whose fracture energy is evaluated using weakest-link statistics. The model naturally predicts that larger aggregates bounce more readily because larger contact regions are more likely to contain weak bonds. Comparison with distinct element method simulations shows that the model reproduces the simulated sticking–bouncing boundary. Furthermore, applying the calibrated model to moderately porous aggregates inferred from ALMA observations of protoplanetary disks, we find that the predicted bouncing barrier passes through the observationally inferred size–velocity range. Thus, our semi-analytic model provides a useful framework for predicting the collisional
evolution of protoplanetary
dust aggregates.
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All authors Sota Arakawa, Haruto Oshiro, Yuki Yoshida, Kiwamu Yoshii
Mesoscale and Nanoscale Physics · Cross-listed from quant-ph
Nonsmooth Bloch Oscillations in Non-Hermitian Systems
Yanyan He and Tomoki Ozawa
Bloch oscillations (BOs) represent a paradigmatic manifestation of force-driven band dynamics in
lattices, conventionally characterized by continuous quasimomentum
evolution and smooth periodic trajectories. Here we show that non-Hermiticity qualitatively changes this paradigm, introducing nonsmooth BOs characterized by cusp-like real-space trajectories and abrupt momentum jumps. Reversing the force switches the dynamics between smooth and nonsmooth BOs, enabling strongly nonreciprocal dynamics. We derive a universal relation for the critical force that governs the nonsmooth-to-smooth dynamical transition in general one-dimensional
lattices, which is induced by a pitchfork bifurcation in momentum space. Our work establishes a unified framework for non-Hermitian BOs and uncovers a fundamental bifurcation mechanism that can generate nonsmooth wave transport in entirely linear systems.
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