Statistical Mechanics
Non-equilibrium quantum dynamics of interacting integrable models by Monte Carlo sampling Lehmann representations
Riccardo Senese and Fabian H. L. Essler
Determining the dynamics of interacting integrable many-particle
quantum systems at finite times after homogeneous
quantum quenches is a long-standing challenge. We present a Monte Carlo sampling scheme that numerically evaluates the Lehmann representation for time-dependent expectation values of local operators, allowing us to access system sizes and times significantly beyond the reach of existing methods. The approach accommodates both the full Lehmann sum and the Quench Action formalism. We
benchmark against exact results for non-interacting
lattice and continuum models and short-time results at weak interactions, finding excellent agreement. We apply the method to
quantum quenches from a Bose-Einstein condensate in the repulsive Lieb-Liniger model and determine the time
evolution of the order parameter for a wide range of interaction strengths. We discuss the emergence of a "sign problem" for more general dynamical correlators and setups.
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Superconductivity
Secondary Collective Excitations in Intermediate to Strong-Coupling Superconductors
Joshua Althüser and Götz S. Uhrig
Considering systematically derived energy-transfer-dependent effective electron-electron interactions leads to the appearance of secondary phase and amplitude modes in isotropic
superconductors in the intermediate-to-strong-coupling regime. We study the implications of such interactions on Bravais
lattices by computing the corresponding response functions using the iterated equations of motion (iEoM) approach. In the weak-coupling regime, we find the conventional, primary amplitude and phase modes at $\omega=2\Delta$ and $\omega=0$, respectively. For intermediate coupling, the amplitude mode detaches from the quasiparticle continuum towards lower energies. Increasing the coupling further leads to additional, long-lived secondary collective excitations below the continuum. This phenomenon is largely independent of the underlying
lattice and the specific
Fermi level. The amplitude and phase modes couple if the system is not particle-hole symmetric. Additionally, we extend the method to compute eigenoperators, i.e., linear combinations of operators that excite each secondary mode specifically. We identify nodal structures in the coefficients for these eigenoperators reminiscent of wave functions in the Hydrogen problem.
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Materials Science · Cross-listed from math-ph
Concurrent enforcement of polyconvexity and true-stress-true-strain monotonicity in incompressible isotropic hyperelasticity: application to neural network constitutive models
Maximilian P. Wollner, Dominik K. Klein, Herbert Baaser et al. (+2 more)
The design of physics-augmented neural networks (PANNs) for the purposes of constitutive modeling has received considerable
attention as of late for a variety of material behaviors. Here, we revisit the classical framework of isotropic incompressible hyperelasticity in light of recent advances in the study of constitutive inequalities. We show that polyconvexity implies true-stress-true-strain monotonicity for a large class of incompressible strain-energy functions. The resulting elastic law obeys the physically reasonable Legendre-Hadamard (or ellipticity) condition as well as the notion of increasing stress with increasing strain. These results then inform the architecture of four distinct PANNs which are subsequently calibrated to three different sets of experimental data each. We show that different PANN parametrizations - satisfying the same constitutive constraints a priori - have varying approximation power for the description of material behavior. Moreover, even when distinct parametrizations perform comparatively well within the calibration regime, they show pronounced differences in extrapolation. This observation motivates a critical discussion about the predictive power of PANNs which also has implications for the modeling of more complex material behavior by virtue of neural networks.
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All authors Maximilian P. Wollner, Dominik K. Klein, Herbert Baaser, Gerhard A. Holzapfel, Patrizio Neff
Strongly Correlated Electrons
Vortex order in magnetic frustrated GeNi$_2$O$_4$ and GeCo$_2$O$_4$ spinels
K. Beauvois, J. Robert, M. Songvilay et al. (+11 more)
In the search for new
spin textures based on singular
magnetic objects like Bloch-points or
vortices, spinel compounds emerge as an interesting playground due to the interplay between
magnetic anisotropy and complex interactions that extend well beyond first neighbors on a pyrochlore
lattice. Based on an exploration of the exchange interaction phase diagrams of members of the Ge$B_2$O$_4$ family with $B$=Co and Ni, we show, using simultaneous modeling of inelastic
neutron scattering measurements and single-
crystal neutron diffraction data, that a 2-$k$
magnetic structure may be stabilized in these compounds. This leads to a short period
spin vortex crystal, a variant induced by the
magnetic anisotropy of the 3-$k$ Bloch-point structure predicted for isotropic
spins. Our study rationalizes the formation of these multi-$k$
spin textures in frustrated antiferromagnets, as well as their anisotropy-dependent
evolution.
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All authors K. Beauvois, J. Robert, M. Songvilay, J. Ollivier, B. Fåk, E. Ressouche, N. Qureshi, R. Ballou, S. Petit, S. Lenne, P. Manuel, S. DeBrion, P. Strobel, V. Simonet
Materials Science
Spin Response Properties in Electronically Robust Ferromagnetic Strained CrSiSe$_3$ Monolayer under External Electric Fields
S. Solihin, Ahmad R. T. Nugraha and Muhammad Aziz Majidi
Integrating two-dimensional van der Waals magnets into field-effect spintronic devices requires robust charge stability and tunable
spin responses. In this study, we investigate the electronic, topological, magnonic, and magneto-optical properties of the strain-engineered
ferromagnetic CrSiSe$_3$ monolayer under out-of-plane external electric fields by using first-principles calculations. We find that for this material, the intrinsic charge sector, including the indirect band gap, charge Berry
curvature, optical conductivities, and magneto-optical Kerr effect spectra, exhibits exceptional robustness against applied fields up to 0.3 V/$\r{A}$. Conversely, the
spin degrees of freedom demonstrate highly sensitive tunability. Electrostatic gating significantly modulates the
spin Berry-like
curvature, driving a non-monotonic enhancement in the
spin Hall conductivity. Furthermore, external fields effectively tune collective
magnon excitations by modifying microscopic Heisenberg exchange interactions. Such coexistence of robust charge immunity and flexible
spin manipulation establishes the strained CrSiSe$_3$ monolayer as a promising platform for stable spintronic devices.
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Strongly Correlated Electrons
Tunable magnetotransport through kinetically hindered first-order phase transitions in an antiferromagnetic metal
Jaime M. Moya, Scott B. Lee, Sudipta Chatterjee et al. (+4 more)
Controllable multilevel resistance states are of interest for
memory technologies like neuromorphic computing, but robust materials platforms toward such behavior remain limited. Here, we show that the non-centrosymmetric
antiferromagnetic metal CeCoGe$_3$ suggests one such route through a kinetically hindered first-order
magnetic transition. Cooling through the kinetically hindered first-order transition in an applied
magnetic field produces a
magnetic glass state in which high- and low-temperature
magnetic phases coexist. The relative fraction of these phases can be controlled by the applied field in which the sample is cooled, and the electrical resistance is directly sensitive to that fraction. As a result, it is demonstrated that CeCoGe$_3$ supports stable multilevel resistive states. These results identify kinetically hindered first-order phase transitions as a promising route towards controllable multilevel magnetoresistive states.
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All authors Jaime M. Moya, Scott B. Lee, Sudipta Chatterjee, Nitish Mathur, Grigorii Skorupskii, Connor J. Pollak, Leslie M. Schoop
Materials Science
Geometry-Dependent Crack Interaction and Toughening in Graphene
Suyeong Jin, Jung-Wuk Hong and Alexandre F. Fonseca
The interaction between neighboring cracks has been shown to strongly influence the fracture behavior of
graphene. While previous studies focused primarily on crack spacing, the role of crack width remains poorly understood. Here, computational simulations are performed to investigate the coupled effects of crack width and inter-crack spacing $(W_\text{gap})$ on the tensile response of
graphene containing parallel cracks. The results show that increasing crack width amplifies the sensitivity of mechanical properties to crack spacing, leading to significant enhancement of peak stress, fracture strain, and toughness at sufficiently large $W_\text{gap}$. For narrow cracks, crack coalescence dominates and causes brittle failure. In contrast, wider cracks promote delayed ligament rupture, increased energy absorption and ductile-like fracture behavior. The normalized toughness and fracture strain exceed those of equivalent single-crack systems by more than twofold. A crack-geometry design map is proposed to identify regimes of crack coalescence, independent propagation, and enhanced toughness.
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Materials Science
Mesoscale Domain Evolution Mechanism during Alternating Current (AC) Poling of Relaxor Ferroelectrics
Yuan-Jie Sun, Bo Wang and Long-Qing Chen
Ferroelectric domain variants that are energetically equivalent are expected to remain preserved during polarization reversal under a
symmetry-preserving electric field. However, recent experiments on relaxor-ferroelectric
crystals have revealed irreversible elimination of inclined domain walls during AC poling, while the underlying mesoscale mechanism remains unclear. Here, we investigate the domain-wall motion during AC poling of rhombohedral Pb(Mg$_{1/3}$Nb$_{2/3}$)O$_3$–PbTiO$_3$ single
crystals containing both 71$^\circ$ and 109$^\circ$ domain walls within a quasi-two-dimensional laminated geometry using phase-field simulations. The simulations reveal that the domain-wall behavior during polarization reversal depends on the spacing ratio between the 71$^\circ$ and 109$^\circ$ domain walls. Closely spaced 71$^\circ$ domain walls undergo irreversible elimination, whereas more widely separated walls are preserved, while the 109$^\circ$ domain walls remain intact. A threshold ratio for domain-wall elimination is identified and found to depend on the mechanical boundary conditions. By tracking the domain-wall trajectories during the switching process, we attribute this behavior to unsynchronized motion of neighboring 71$^\circ$ domain walls arising from long-range elastic interactions when the walls become strongly coupled. This collective motion breaks the
symmetry between energetically equivalent domain variants and leads to irreversible domain-wall elimination during polarization reversal. These findings provide mechanistic insight into collective domain-wall
evolution during polarization reversal and suggest that proximity-driven
symmetry breaking may provide a mesoscale mechanism for domain engineering in ferroelectric materials with high domain-wall densities.
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Mesoscale and Nanoscale Physics
Ellipticity effects on diffusive magnon spin and heat transport in easy-plane ferromagnets
Nicolas Vidal-Silva and Alejandro O. Leon
When a
magnetic material hosts
spin-wave excitations, or
magnons, the local magnetization can rotate in circular or elliptical orbits, the latter arising naturally in the presence of
magnetic anisotropies transverse to the
equilibrium magnetization. This article investigates the diffusive transport of elliptical
magnons in easy-plane ferromagnets. Our analysis starts with the derivation of the
magnon dispersion relation and
magnon spin from the Landau-Lifshitz-Gilbert equation with a perpendicular
magnetic anisotropy. Then, using the Boltzmann transport equation in the relaxation time approximation and perturbation analysis, the
magnon-
spin and
magnon thermal conductivities are obtained, quantifying the
magnon transport in the
insulator. Our calculations demonstrate that, in both three- and two-dimensional systems, the effects of ellipticity on
magnon transport coefficients result in an enhancement or a decrease, depending on whether magnets with a easy or hard perpendicular-to-plane axis are considered, respectively. On the other hand, our results predict an enhancement of the
magnon heat transport for both easy- and hard-axis
magnetic systems. Our study supports previous works on
magnon ellipticity and makes a step towards clarifying its effect on
magnon transport properties.
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Materials Science
Adaptive Slater Koster Parameters: Crossing Oxidation States with Density Functional Tight Binding
Yihua Song, Artem Samtsevych, Anton Beiersdorfer et al. (+4 more)
We propose to adapt the confined pseudo-atomic orbitals underpinning the precalculated Slater-Koster (SK) interaction tables in Density Functional Tight Binding (DFTB) to local atomic environments. We demonstrate significant improvement in electronic structure and energetics in the application to a partially oxidized Ni surface and Li insertion into graphite, where we assign optimal SK parameters to metal atoms in different oxidation states. Further analysis reveals the smoothness of the SK integrals across the varying oxidation states. Exploiting this, we introduce a site-resolved machine-learning scheme for fully adaptive DFTB. Using atomic descriptors and simple regression architectures already established in the context of machine-learning interatomic potentials, our scheme achieves 95% band-structure accuracy across all Ni-O binary compositions in the Materials Project.
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All authors Yihua Song, Artem Samtsevych, Anton Beiersdorfer, Tobias Melson, Christoph Scheurer, Karsten Reuter, Chiara Panosetti
Strongly Correlated Electrons
PEPSKit.jl: A Julia package for projected entangled-pair state simulations
Paul Brehmer, Lander Burgelman, Zheng-Yuan Yue et al. (+3 more)
We present PEPSKit$.$jl, a Julia package for simulating two-dimensional
quantum many-body systems with infinite projected entangled-pair states (iPEPS). PEPSKit$.$jl builds on the TensorKit$.$jl package for tensor computations and provides high-level
algorithms for iPEPS simulations that support both Abelian and non-Abelian
symmetries, as well as fermionic systems. This work gives an overview of the main package features, which include support for ground-state, time-
evolution, and finite-temperature simulations in systems with different physical
symmetries and
lattice geometries. These capabilities are illustrated through various examples and technical
benchmarks.
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All authors Paul Brehmer, Lander Burgelman, Zheng-Yuan Yue, Gleb Fedorovich, Jutho Haegeman, Lukas Devos
Strongly Correlated Electrons · Cross-listed from hep-th
Stringy T-duality on the lattice and the twisted Villain model
Coraline Bacq, Alessio Caddeo, Saskia Demulder et al. (+1 more)
We address the question of whether dualities formulated in continuum field theory can be realised exactly at finite
lattice spacing, rather than only emerging in the infrared. In this context, we construct a
lattice framework for a genuinely stringy form of T-duality. We extend the exact
lattice T-duality of the compact
boson to curved backgrounds with non-trivial circle fibrations, where the duality is no longer exhausted by the familiar exchange of momentum and winding, but also involves global topological data. To this end, we define the twisted Villain model, which couples the
lattice fibre field to cochains encoding the bundle connection and the fibre-horizontal component of the $B$-field. We realise this structure in
lattice models for several fibred backgrounds and recover the characteristic bundle-flux exchange of T-duality. Using a half-gauging procedure, we derive the associated
lattice defect action and show that it defines a topological defect. This establishes that the distinctive topological features of T-duality on curved
manifolds can be captured exactly in a
lattice model, implying that this duality is not tied to a particular continuum representation is present in
lattice-regularised models.
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All authors Coraline Bacq, Alessio Caddeo, Saskia Demulder, Johanna Erdmenger
Other Condensed Matter
Self-Decelerating Bright Exciton-Polariton Solitons in Bound-State-in-Continuum Microcavities
Xingran Xu and Chunyu Jia
We theoretically investigate the formation and dynamics of bright
exciton-polariton
solitons within systems engineered to support Bound States in the Continuum. By employing a driven-dissipative Gross-Pitaevskii equation coupled with a rate equation for the excitonic reservoir, we demonstrate that BICs provide a robust platform for stabilizing the condensate against radiative decay. Utilizing a Lagrangian variational approach, we derive analytical expressions describing the trajectory and velocity of these bright solitonic excitations. Notably, we find that the propagation of these BIC-engineered
solitons exhibits a distinct self-deceleration, eventually bringing them to a halt at a final position dictated by the initial conditions and intrinsic system parameters. Furthermore, we analyze the dynamical stability of these
solitons. Our findings offer valuable insights into the manipulation of polaritonic flows in non-Hermitian systems.
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Mesoscale and Nanoscale Physics
Non-Hermitian thermoelectric transport in graphene: Tunable anomalous transmission through complex barriers
Daniel A. Bonilla, Juan A. Cañas, J. C. Pérez-Pedraza et al. (+1 more)
We investigate thermoelectric transport in monolayer
graphene across a finite complex barrier within a Landauer scattering framework. Solving the Dirac-Weyl problem exactly, we show that the imaginary part of the barrier renders the scattering
matrix nonunitary and replaces the usual Hermitian flux conservation by a generalized flux-balance relation determined by the net gain or loss inside the barrier. In the Hermitian limit, the standard
graphene $n$-$p$-$n$ barrier behavior is recovered, including perfect transmission at normal incidence and Fabry-Perot-type resonances. For a finite imaginary part, however, the same resonant channels are selectively attenuated or amplified, which significantly modifies both the angular response and the conductance profile. We further show that the lead-resolved conductances become dependent on the bias partition, providing a direct signature of the breakdown of gauge invariance in the effective two-terminal response. At finite temperature, the exact linear-response coefficients reveal a clear trade-off controlled by the imaginary part of the barrier: gain enhances both the electrical and thermal conductances, whereas loss suppresses the thermal conductance more efficiently and yields the largest thermoelectric figure of merit within the parameter range considered. These results demonstrate that complex barriers extend the range of transport behaviors accessible in
graphene beyond the usual Hermitian $n$-$p$-$n$ junction. They also suggest a practical interpretation of the imaginary potential as an effective reduced description of unresolved source-sink channels or additional probes coupled to the device, particularly when a fully microscopic model of the environment is not available.
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All authors Daniel A. Bonilla, Juan A. Cañas, J. C. Pérez-Pedraza, A. Martín-Ruiz
Materials Science
Realization of a parity-violating antiferromagnetic state in LaMnSi
Takuma Iwata, K. Shiraishi, T. Aoyama et al. (+12 more)
Spontaneous
symmetry breaking underlies functional electronic phenomena in
quantum materials. Breaking space-inversion ($\mathcal{P}$) or time-reversal ($\mathcal{T}$)
symmetry can generate
spin-split electronic bands central to modern spintronics. By contrast, parity-violating
antiferromagnetic (AFM) order breaks both $\mathcal{P}$ and $\mathcal{T}$ while preserving the combined $\mathcal{PT}$
symmetry, enabling
spin-degenerate yet momentum-asymmetric electronic bands. This momentum asymmetry has been proposed as a microscopic origin of unconventional nonreciprocal and nonlinear responses but its experimental verification has remained challenging because it requires establishing both the
symmetry-breaking
magnetic order and the associated electronic structure. Here we combine soft x-ray angle-resolved photoemission spectroscopy (ARPES) and polarization-resolved optical second-harmonic generation (SHG) microscopy to study LaMnSi, a candidate parity-violating AFM metal. Soft x-ray ARPES resolves the three-dimensional bulk band structures in agreement with density functional theory calculations for the AFM phase, whereas SHG microscopy detects sign-reversing nonlinear optical responses from opposite AFM domains that carry $\mathcal{T}$-odd parity-violating order. Together, these results provide direct evidence for parity-violating AFM state in LaMnSi, establish LaMnSi as a parity-violating AFM metal, and identify this class of AFMs as a promising platform for
symmetry-controlled nonreciprocal and nonlinear electronic responses.
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All authors Takuma Iwata, K. Shiraishi, T. Aoyama, D. Senba, T. Takeda, Y. Fujisawa, M. Nurmamat, K. Nakanishi, K. Yamagami, M. Arita, T. Yamada, Y. Yanagi, A. Kimura, H. Tanida, Kenta Kuroda
Mesoscale and Nanoscale Physics
Twisted light generates robust many-body states for practical quantum computing
Ferney J. Rodriguez, Luis Quiroga and Neil F. Johnson
Twisted light carries orbital angular momentum (OAM) and can drive excitations of confined, interacting electrons that are dark to uniform dipolar probes. Here we show how this “beyond-Kohn's-
Theorem” optical channel can become a concrete control primitive for
quantum computing. Correlation sectors in few-electron
quantum dots – characterized by the relative angular momentum
quantum number – form a tunable ladder of many-body states that are robust in the limited sense of
symmetry-protected selection rules and persistent
chiral spectroscopic fingerprints; full topological gap protection requires three or more electrons. A twisted-light pulse with prescribed OAM index and polarization provides fast optical write, read, and scalable addressing of these sectors via the selection rule $\Delta|m|=\pm(l+\sigma)$. In the analytically solvable Calogero ($1/r^2$) interaction limit, both the energy spectrum and the twisted-light
matrix elements are closed-form functions of the interaction strength, allowing gate parameters (Rabi frequency,
qubit frequency, anharmonicity, and leakage rates) to be written down explicitly. We map these results onto a universal single-
qubit gate set, propose a concrete two-
qubit entangling mechanism via state-dependent Coulomb coupling between adjacent dots, and identify the dominant decoherence channel (quadrupolar charge noise). A semi-analytic $N=3$ extension using the $1/N$ expansion provides a design-level scaffold for the topological roadmap, including quasihole sector addressing. The central operational message is that twisted light enables WRITE (pulse-create a correlation sector), READ (spectroscopically diagnose correlations), and SCALE (optical addressing via spatial light modulator) in a unified photonic control layer. Throughout, screened and Coulomb interactions preserve the same qualitative
chiral fingerprints established in the solvable limit.
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Materials Science · Cross-listed from physics.chem-ph
Accelerated "on-the-fly" coupled-cluster path-integral molecular dynamics: Impact of nuclear quantum effects on an asymmetric proton
Thomas Spura, Hossam Elgabarty and Thomas D. Kühne
We present an accelerated “on-the-fly” coupled-cluster path-integral molecular dynamics (PIMD) method for finite-temperature simulations in which electron correlation and
nuclear quantum effects are treated simultaneously. The approach is based on our
quantum ring-
polymer contraction (qRPC) technique, in which the inexpensive Hartree-Fock potential is evaluated on the full ring-
polymer, while the expensive coupled-cluster correction is evaluated on the centroid only. This qRPC decomposition is combined with a second-generation Car-Parrinello-like dynamics of the Hartree-Fock reference and a basis-consistent extrapolation of the coupled-cluster and de-excitation amplitudes. The combination of all three acceleration layers is essential for making correlated PIMD calculations feasible. We apply the method to a
proton shared by water and formaldehyde. Relative to classical
nuclei,
nuclear quantum effects broaden covalent X–H bond-length distributions, reduce the bias of the shared
proton toward formaldehyde, and shift the mean
proton-transfer coordinate from 0.206 to 0.135A. The probability of finding the
proton closer to formaldehyde decreases from 81.7$\%$ to 61.1$\%$. The corresponding
nuclear magnetic shielding tensors show that electron correlation and
nuclear quantum effects are of comparable magnitude and can act in opposite directions. These results demonstrate that predictive simulations of asymmetric hydrogen bonds require a simultaneous treatment of correlated electronic structure and
nuclear quantum fluctuations.
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Soft Condensed Matter
Percolation of a cohesive fine particle in a static bed
Jizhi Zhang, Qiong Zhang, Julio M. Ottino et al. (+2 more)
Percolation of fine particles (fines) in a static bed of larger particles is central to many industrial and natural processes. Non-cohesive fines either pass through the bed or become trapped depending on multiple factors including particle sizes, friction and restitution coefficients, and size-polydispersity. Here we consider the additional factor of cohesion. We use the discrete element method to simulate
gravity-driven percolation of cohesive fine particles through a static bed of randomly packed large particles; fines interact with bed particles but not with each other. A large-to-fine particle diameter ratio of 7 geometrically permits non-cohesive fines to pass the narrowest pore throats formed by the large particles so they can freely percolate. However, sufficiently large cohesion and friction lead to non-
geometric trapping. Fines are trapped when they fail to rebound after a collision, due to large cohesion, low restitution, and low collision velocity, and any subsequent rolling or sliding is insufficient to cause detachment. This establishes a sequence of local interactions – collision, adhesion, and post-contact motion – that governs the ultimate fate of a fine particle. A collisional model that incorporates a trapping probability per collision and a collision frequency predicts the trapping distance in the regime dominated by collision-induced trapping. For non-rebounding collisions, frictional effects are enhanced by cohesion and, when large enough, prevent the fine particle from subsequently detaching. A static
equilibrium condition based on force balance predicts whether a fine particle remains stationary after contact. These results show that percolation of cohesive fine particles is not determined by
geometric accessibility alone, but also by particle-scale interaction dynamics that can override
geometric expectations.
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All authors Jizhi Zhang, Qiong Zhang, Julio M. Ottino, Paul B. Umbanhowar, Richard M. Lueptow
Statistical Mechanics
Ground-state Entropy of the Ising model on a Frustrated lattice
B Sriram Shastry, Bill Sutherland, Frédéric Mila et al. (+1 more)
We report the ground-state
entropy of a 2-d Ising model on the Shastry-Sutherland
lattice. We also study a generalization of this model, where a constraint on the zero temperature allowed configurations is removed continuously.
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All authors B Sriram Shastry, Bill Sutherland, Frédéric Mila, Afonso Rufino
Strongly Correlated Electrons
Geometric curvature driven by many-body collective fluctuations
Alejandro S. Miñarro and Gervasi Herranz
Quantum geometry characterizes the variation of wavefunctions in momentum space through their overlaps and relative phases, providing a general framework for understanding many transport and optical properties. It is generally formulated in terms of interband
matrix elements, which, entering the response functions, allow obtaining experimental access to the
quantum geometric tensor. Recently, it has been emphasized that
quantum geometry can also be interpreted in terms of
quantum dipole fluctuations in the ground state driven by interband mixing. Here, we extend this picture to include contributions from many-body collective fluctuations, in which propagators and response vertices are dressed dynamically by the interaction with collective modes. Focusing on the Berry
curvature, we show that contributions from collective fluctuations can be experimentally distinguished from bare band-
geometric contributions, via specific antisymmetric channels in inelastic scattering spectra. We further identify the non-commutative properties of transverse
quantum fluctuations as well as non-local-time interactions as the generators of this dynamical
curvature in the susceptibility response.
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Mesoscale and Nanoscale Physics · Cross-listed from hep-th
Spin Hall effect and Berry curvature of gravitons from quantum field theory
Ritsuki Ito, Kazuya Mameda and Naoki Yamamoto
Based on
quantum field theory of linearized
gravity, we formulate the Wigner function for right- and left-handed gravitons. By applying the Wigner transformation to the second-order metric perturbations in the graviton energy-momentum tensor obtained from the Einstein-
Hilbert action, we demonstrate the emergence of the
spin Hall effect of gravitons in curved spacetime. This effect originates from the Berry
curvature of gravitons, which has opposite signs for right- and left-handed helicities, and leads to a helicity-dependent splitting of the graviton energy
Hall current. The magnitude of this splitting is found to be exactly twice that of the corresponding
spin Hall current for
photons.
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Materials Science
Partially reactive force field for the UiO-66 metal-organic framework
Akanksha Nawani and Rocio Semino
UiO-66 is the most widely studied metal-organic framework, on account of its structural tunability given by its capacity of sustaining high amounts of point defects in its structure. Its synthesis mechanism is largely unknown, with only a few works mostly focused on the formation of the Zr-
oxide cluster. In this work, a partially reactive force field to model UiO-66, nb-UiO-FF, is introduced. This force field incorporates node–ligand reactivity via a Morse potential and the introduction of dummy atoms to reproduce the anisotropic charge distribution of the Zr atoms in the node. nb-UiO-FF reproduces structural features of both UiO-66 and its isoreticular analog UiO-67 as well as framework stability with or without defects, activated or filled with N,N-dimethylformamide or ethanol. Defect generation and node–ligand binding energies are comparable with density functional theory values. The force field is further employed within a molecular dynamics scheme to study the early stages of solvothermal node–ligand binding. Species with structures corresponding to motifs present in UiO-66 are observed, along with other metastable species. This force field enables studying the self-assembly of UiO-66, as well as the formation of its point defects.
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Materials Science
Building a Regional Data-Centric Materials Science Ecosystem for Processing-Rich Materials Innovation in the Great Plains
D.-M. Mei, K. Acharya, C. M. Adhikari et al. (+52 more)
Data-centric materials science is changing how materials are discovered, optimized, manufactured, and qualified, yet many deployment-limiting materials problems still depend on experimental, processing-rich, device-level, and field-relevant data that are difficult to capture in conventional materials databases. This perspective argues that the Great Plains and adjacent interior research corridor can make a distinctive national contribution by organizing distributed experimental assets into a trusted regional materials-data ecosystem. The proposed model emphasizes FAIR metadata, provenance, persistent sample identifiers, uncertainty-aware modeling, semi-closed-loop workflows, stackable workforce training, and tiered governance for academic, public, controlled-access, and industry-protected data. We identify five coupled barriers – fragmented data, weak
algorithm–laboratory translation, uneven access to cyberinfrastructure and technical staff, workforce gaps at the materials–data interface, and insufficient incentives for sharing and reuse – and propose a staged roadmap for addressing them. A high-purity germanium pilot illustrates how regional strengths can be converted into reusable
datasets,
benchmark models, trained personnel, and decision-improving workflows. The broader message is that regional leadership in data-centric materials science will depend less on geographic concentration than on trustworthy data practices, interoperable infrastructure, cross-trained people, and application-driven materials challenges.
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All authors D.-M. Mei, K. Acharya, C. M. Adhikari, M. Adhikari, S. Aryal, B. V. Benson, K. Bhatta, S. Bhattarai, N. Budhathoki, A. M. Castillo, D. Chakraborty, S. Chhetri, S. Choudhury, T. A. Chowdhury, R. D. Cruz, B. Cui, S. Dhital, K.-M. Dong, R. Gapuz, A. Ghasemi, E. Z. Gnimpieba, B. D. S. Gurung, H. A. Hashim, R. I. Harry, K.-E. Hasin, M. K. Hassanzadeh, M. K. Jha, D. Kim, K.-C. Kong, B. Lama, A. Mahat, N. Maharjan, A. Majeed, J. Mammo, M. M. Masud, K. S. Moore, T. Mukherjee, A. Nawaz, H. Oli, S. A. Panamaldeniya, L. Pandey, R. Pandey, Z. Peng, A. Prem, M. M. Rana, K. Rana Magar, R. Rizk, C. S. Tadi, L.-W. Wang, Y. Yang, G.-L. Yin, C.-X. Yu, D. Zeng, M. Zhou, Q. Zhou
Soft Condensed Matter
Function, Complexity and Thermodynamics in Adaptive and Intelligent Soft Matter Systems: An Information-Theoretical Framework
George S. Attard
The terms responsive, adaptive and intelligent are widely used in soft matter and materials science but remain qualitative, with no quantitative basis for comparing systems from different areas on a common axis. We address this by treating any stimulus-coupled material as an information channel. The three classes are distinguished by kernel conditioning: a memoryless map p(y|x) (responsive), a state-conditioned map p(y|x,s) (adaptive), and a feedback-modified channel with
memory (intelligent). Three information-theoretic metrics follow: configurational diversity I1, functional selectivity I2, and stimulus-response information transfer I3. Because the kernel and substrate are the same object, a heuristic non-monotonic relationship arises between internal complexity and realised information transfer, with an optimal complexity N* set by transmission efficiency, stimulus energy and thermal noise. We propose two benchmarking planes: a dynamic plane (volumetric information rate I3/V versus power density P, referenced to the Landauer-Berut floor) and a static plane (I1, I2). Sixteen systems spanning synthetic soft matter, biology and hard matter separate into broad bands above the
benchmark: ~10^18-10^20x for soft matter and shape-
memory alloys, 10^10-10^16x for silicon and electromechanical devices, 10^9-10^10x for neuromorphic memristors, and 10^5-10^8x for evolved biology, with an ER lipid network near 10^11x. Each placement carries an uncertainty of one to two decades per axis; the band ordering nonetheless appears robust. The gap between synthetic soft matter and biology is tentatively attributed to the per-element substrate energy scale (1-10 kBT versus 10^4-10^5 kBT). The framework is offered as a foundation that may lead to validated design rules; three routes are proposed by which soft matter's separation from the Landauer
benchmark might be reduced.
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Disordered Systems and Neural Networks
Optimal Persistence Reveals Hidden Topology in Complex Energy Landscapes
LI Zhenpeng
Infinite persistence marks the topological transition. For finite persistence, the canyon-finding rate Gamma(tau_p) on the p=2 spherical
spin glass forms an inverted-U profile, peaking at an optimal tau_p^*. At low temperature (T=0.05), tau_p^* drops from 10 to 5 as N increases through 128, marking the discrete-to-quasi-continuous GOE crossover. For N=1024, the peak is flat between tau_p=5 and 6 within statistical uncertainties, preventing a more precise determination. For N>=128, the canyon width saturates at xi_eff=1, consistent with the measured tau_p^*=5 when beta=0.4. At higher temperatures (T>=0.15), tau_p^*=10 and beta(T) scales as 1/T, with temperature dependence entering only through v_th = sqrt(2T). For T=0.10 and N>=128, high-resolution scans give tau_p^*=8.0; for N<=64 at the same temperature, coarse scans place tau_p^* in the range 8-10. Thus, optimal persistence reveals the hidden
topology of the landscape-a principle expected to be generic in disordered landscapes with entropic bottlenecks.
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Materials Science
Direct Simulation of LiNi0.8Mn0.1Co0.1O2 Transport Properties Using an Efficient and Accurate Machine Learning Potential
Jian He, Constantijn H. J. A. van de Wetering, Rolande W. Nolsen et al. (+1 more)
The rate capability of layered lithium nickel manganese cobalt
oxide (NMC) cathode materials plays a decisive role in high-power applications such as fast charging, necessitating a detailed understanding of lithium-ion
diffusion. However, the mechanisms governing lithium-ion transport in NMC remain insufficiently understood, both experimentally and computationally. In this study, we employ an advanced and efficient machine learning potential (MLP) to simulate lithium self-
diffusion in LiNi0.8Mn0.1Co0.1O2 (NMC811), enabling direct large-scale molecular dynamics (MD) simulations. The workflow integrates a fine-tuned MACE (Message Passing Atomic Cluster Expansion) foundation model as a structural generator and leverages an active learning strategy applied to a near-ground-state
dataset. This approach enables the construction of a reliable MLP for NMC811 in a data-efficient manner using a limited number of density functional theory (DFT) reference calculations. Based on this potential, we performed MD simulations to predict lithium
diffusion coefficients. The MLP-based simulations preserve the accuracy of DFT while overcoming its time and length scale limitations, thereby allowing direct simulation of lithium self-
diffusion in NMC811.
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All authors Jian He, Constantijn H. J. A. van de Wetering, Rolande W. Nolsen, Nongnuch Artrith
Materials Science
$G_0W_0$@HF and BSE methods in periodic systems from Hartree-Fock theory: gaussian orbital and density fitting approach
Charles H. Patterson
The $GW$ method for calculating quasi-particle energies of solids commonly begin from a DFT
Hamiltonian and Kohn-Sham orbitals in a plane wave basis. Screening of the coulomb interaction is implemented using the inverse dielectric function in the random phase approximation (RPA). We present $G_0W_0$ calculations which begin from the Hartree-Fock method in a basis of gaussian orbitals. The screened coulomb interaction, $W$, is obtained using a $W$ = $v$ + $v\Pi v$ approach without invoking a plasmon pole approximation. The polarizability, $\Pi$, in $W$ is treated at the RPA level. RPA polarizabilities require solution of Bethe-Salpeter equations (BSE) for each unique $\textbf{Q}$ point. A strategy for obtaining self-energies which are converged with respect to number of virtual states is employed in which $G_0W_0$ yields the majority of the self-energy and the remaining part from high energy virtual levels is evaluated at second-order. The methods are evaluated by applying them to elemental
semiconductors (C, Si) and
oxides (MgO and anatase and rutile TiO$_2$). Common errors of HF theory applied to materials include overestimation of both the band gap and valence band widths. These are corrected in the approach employed here. Typically, the RPA screened interaction results in overestimation of band gaps while the $G_0W_0$ self-energy band width renormalization yields band widths for diamond and Si which are in good agreement with experiment. HF calculations are performed in gaussian orbital basis sets and $G_0W_0$ and BSE calculations are performed using density fitting with a coulomb metric.
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Strongly Correlated Electrons
Filling-Sensitive Spectral Complexity from Hilbert-Space Holonomy in Fragmented Non-Hermitian Systems
Jiong-Hao Wang, Maria Zelenayova, Christopher Ekman et al. (+1 more)
We show that
Hilbert-space holonomy provides a
geometric organizing principle for spectral reality in fragmented non-Hermitian many-body systems, complementary to conventional
symmetry protection. In two minimal fragmented models, complex spectra can arise only within the most symmetric sectors: half filling in the
fermion model and zero magnetization in the
spin chain. Adding or removing a single particle, or flipping a single
spin, renders the spectra entirely real despite unchanged periodic boundary conditions, reminiscent of boundary-condition sensitivity in systems with a non-Hermitian skin effect. We explain this by viewing nonreciprocal hopping amplitudes as a discrete gauge field on the Krylov graph: trivial holonomy permits a diagonal similarity transformation to the Hermitian limit, whereas nontrivial holonomy obstructs it and allows complex spectra. In certain regimes, trivial holonomy admits an emergent-boundary interpretation, and longer-range models exhibit finite real and complex regions governed by the same criterion.
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All authors Jiong-Hao Wang, Maria Zelenayova, Christopher Ekman, Emil J. Bergholtz
Mesoscale and Nanoscale Physics
Polar optical scattering in ellipsoidal nanoclusters
Hrach Nikoghosyan and Gor Nikoghosyan
The influence of the specific geometry of three-dimensional confinement on electron- vibrational coupling in InAs/GaAs nanoclusters shaped as highly oblate ellipsoids of revolution is considered. Optical
phonon relaxation processes are analyzed taking into account the law of conservation of angular momentum projection and the spatial
symmetry of the dimensional confinement. The conditions for the emission of
chiral optical
phonons carrying orbital angular momentum along the structure's growth axis are analyzed. Intraband relaxation transitions with the emission of LO
phonons with zero angular momentum, with characteristic anisotropy of the emission direction, leading to nonmonotonic size dependences for the e-ph coupling coefficient, are considered.
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Soft Condensed Matter
The fracture resistance of elastic networks increases with the density of defects like a random walk
Antoine Sanner, Luca Michel and David S. Kammer
Disordered spring networks are a well-established model system to study fracture in a wide range of materials, from ceramics to
polymer networks and mechanical metamaterials, across length scales from the atomistic to the macroscopic. A central quantity characterizing fracture is the apparent fracture energy $G^c$, which measures the resistance to the propagation of a preexisting dominant crack. While it is well established that disorder can increase $G^c$ through crack arrest by local inhomogeneities, its dependence on the degree of disorder remains poorly understood. Here, we study the effect of varying concentrations of missing bonds on crack propagation of an otherwise perfect two-dimensional triangular network of springs. For a given network with a fixed concentration of missing bonds, the apparent fracture energy $G^c(a)$ increases with crack advance $a$. This behavior can be explained by mapping the effect of the missing bonds onto an equivalent local fracture energy landscape $\Gamma^{loc}(a)$ and applying established theories linking planar crack arrest with fluctuations in $\Gamma^{loc}(a)$. For increasing fraction of missing bonds $\nu$, the standard deviation of the fluctuations of $\Gamma^{loc}$ increases with $\sqrt{\nu}$, which we explain by considering a random-walk-like superposition of perturbations caused by individual missing bonds. We demonstrate that as a consequence of crack arrest by fluctuations in $\Gamma^{loc}$, the average $G^c(a)$ follows the same $\sqrt{\nu}$ scaling. Furthermore, we observe that the probability density of $\Gamma^{loc}$ has an exponential tail leading to a logarithmic increase of $G^c(a)$ with crack advance $a$. Our results quantitatively link microstructural disorder to macroscopic fracture energy and paves the way for quantitative predictions of the fracture energy in a wide variety of materials.
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