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Physics Condensed Matter

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Monday 30 March

Quantum Gases

Moiré and frustration physics of dipolar supersolids under periodic confinement

We study the ground-state phases of a two-dimensional dipolar supersolid subjected to external periodic confinement by numerically solving the extended Gross–Pitaevskii equation. Focusing on a regime in which the unconfined system forms an intrinsic triangular droplet crystal, we consider triangular, honeycomb, and square optical lattices and classify them into isostructural and heterostructural settings relative to the spontaneous supersolid order. We map out the stationary states as functions of the lattice depth $V_0$ and the commensurability ratio between the intrinsic droplet spacing and the external lattice period. For triangular and honeycomb confinements, the competition between the soft self-organized supersolid lattice and the rigid external potential can generate long-wavelength moiré superstructures in the weak- to intermediate-lattice regime, together with a sequence of reconstructed states including ring-like clusters and stripe-segment configurations. By contrast, the square lattice introduces strong symmetry mismatch between the intrinsic $C_6$ order and the imposed $C_4$ geometry, leading to frustration-induced anisotropic states and symmetry-reduced cluster arrangements. Our results establish dipolar supersolids under periodic confinement as an unconventional route to exploring moiré physics, where moiré superstructures arise from the competition between a self-organized soft lattice and an externally imposed rigid one.
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Mesoscale and Nanoscale Physics

Frequency Comb of Electric-Polarization Waves

Frequency combs are a spectrum of equally spaced frequency components with very high time-frequency accuracy, which have been widely used in the optical and microwave frequency ranges. We propose the realization of a frequency comb operating at the terahertz regime in terms of the nonlinear dynamics of electric-polarization waves, or ferrons as their quanta, in the ferroelectric materials. The efficiency of the frequency comb of the electric-polarization waves is exactly proportional to the static electric polarization carried by the ferron modes, which thereby offers new opportunities for the direct observation and application of the intrinsic properties of ferrons.
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Superconductivity

Pumping of spin supercurrent in unitary triplet superconductors

One efficient mechanism for generating a charge supercurrent is Andreev reflection, in which the electric current injected from a normal metal into a conventional superconductor is converted into a supercurrent, thereby preserving charge conservation. We here propose a general principle for generating spin supercurrents in triplet superconductors by analogy with such charge transport, i.e., assuming spin conservation. We find a spin torque that is proportional to the triplet superconducting order parameter and, in the spin-conservation scenario, converts the particle spin to that of Cooper pairs. Based on this general principle, we propose an implementation to efficiently generate a spin supercurrent in unitary triplet superconductors, even though Cooper pairs carry no spin polarization at equilibrium, by the magnetization dynamics ${\bf M}(t)$ of a proximity magnetic nanostructure. The efficiency of this spin pumping is not solely limited to the $d{\bf M}/dt\times {\bf M}$ due to the emergent particle-hole symmetry, thereby going beyond the conventional spin pumping of electrons. This general principle provides an efficient approach to generating and manipulating dissipationless spin currents in many unconventional superconductors.
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Statistical Mechanics · Cross-listed from math-ph

A symmetry formula for correlation functions in the superintegrable chiral Potts spin chain

We prove an exact finite-volume symmetry formula for two-point functions in the periodic $N$-state superintegrable chiral Potts spin chain. We show that, for every chain length $L$ and every simultaneous eigenvector of the Hamiltonian and the one-site translation operator, the correlations satisfy $\langle Z_0^r Z_R^{\dagger r}\rangle^*=\langle Z_0^r Z_{L-R}^{\dagger r}\rangle$ for $1\leqslant r\leqslant N-1$. Hence, whenever $L$ is even, the midpoint correlation $\langle Z_0^r Z_{L/2}^{\dagger r}\rangle$ is real. Then we generalise the three-state chain case to arbitrary $N$ and to every translation eigensector. This resolves a conjecture of Fabricius and McCoy.
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Disordered Systems and Neural Networks

Magnetic doping-induced second-order and first-order topological phase transition inthe photonic alloy

The bulk-edge correspondence principle, a cornerstone of topological physics, ensures that first-order topological systems host robust chiral edge states in two dimension. This was later extended to higher-order phases, where second-order topological insulators exhibit localized, topologically protected corner states. While the transition between these distinct phases has been demonstrated in periodic systems, its existence in disordered platforms remains an open question. Here, we demonstrate a controllable topological phase transition between a second-order topological phase and a first-order topological phase in a two-dimensional photonic alloy. By tuning the magnetic doping concentration - implemented by attaching permanent magnets randomly to nonmagnetized yttrium iron garnet rods in an alternately magnetized honeycomb lattice with C3 rotational symmetry - we flexibly control the system's topology. At zero doping, we observe higher-order corner states, confirmed by a trivial Chern number and non-zero bulk polarizations of 1/3. As doping concentration increases, these corner states progressively merge with the bulk states, culminating in the closure of the bulk transmission gap. After the bulk transmission gap reopens with further increased doping, the system transitions to a first-order topological phase, characterized by a nontrivial Chern number of -1 and the emergence of a chiral edge state. This transition is reversible, providing a highly tunable and experimentally simple platform for flexibly switching between localized corner states and delocalized chiral edge states within a single photonic system.
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All authors Xianbin Wu, Tiantao Qu, Xiaoxuan Shi, Lei Zhang, Jun Chen

Soft Condensed Matter

Developments in Multi-Chain Coarse-Grained Models for Entangled Polymer Dynamics

This review describes the development and applications of multi-chain coarse-grained simulations for entangled polymer dynamics. The mean-field tube model has long served as the standard paradigm for describing the many-body entanglement problem as the motion of a single chain in a static field; it faces intrinsic limitations when addressing spatial correlations, fluctuations, and complex topological rearrangements. To overcome these limitations, "multi-chain" approaches – specifically the primitive chain network and multi-chain slip-spring models – were developed. These simulations explicitly resolve the force balance and topological coupling between multiple chains in three-dimensional space. This review covers the primitive chain network model, which emphasizes real-space force balance, and the multi-chain slip-spring model, which is derived from a well-defined free-energy functional. Linear and nonlinear rheology predictions are discussed, along with molecular mechanisms such as constraint release and stretch/orientation-induced reductions in friction. Extensions to branched polymers, wall-slip phenomena, and network polymers are also mentioned.
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Materials Science

Raman and Terahertz Spectroscopy of Low-Frequency Chiral Phonons in Amino Acids

Chiral phonons are mirror-symmetric vibrations that correspond to twisting and rotational motions of atoms. In chiral biomolecules, they correspond to low-energy terahertz (THz)-range vibrations of the molecular segments involving dozens of atoms whose energies are sensitive to the chirality of the molecules and local atomic geometries. Here we present spectral signatures of chiral phonons in circularly polarized low-frequency Raman and Raman optical activity (ROA) spectra from crystals of several amino acids in different enantiomeric forms. Along with complementary THz circular dichroism (TCD) measurements, our ROA data reveal two sets of bisignate peaks in valine, alanine, tyrosine and proline between 1 and 4.5 THz that are more intense than the ROA peaks in the fingerprint region. Density functional theory (DFT) calculations on L-alanine attribute these modes to twisting and shearing molecular motions. The strong agreement between the ROA and TCD data demonstrates the power of these complementary vibrational spectroscopy techniques to identify chiral phonons in biomolecules, and offers new insights into their vibrational properties and interactions with circularly polarized light.
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All authors Rahul Rao, Won Jin Choi, Joseph M. Slocik, Thuc T. Mai, Michael A. Susner, Kelsey A. Collins, Michael J. Newburger, Petr Bouř, Nicholas A. Kotov

Sunday 29 March

Materials Science

Localization-driven exchange contrast in diffusion exchange spectroscopy

Diffusion exchange spectroscopy (DEXSY) is a method to probe exchange between domains of varying confinement. Analyses of DEXSY signals typically assume Gaussian diffusion within distinct compartments and first-order exchange kinetics between them. Other situations can yield DEXSY signal contrast with respect to mixing time, however, leading to potentially erroneous interpretation. Here, we demonstrate that a one-dimensional compartment with reflecting boundaries and without relaxation can by itself produce such contrast in certain experimental regimes. The origin of this contrast is the diffusive mixing of spin isochromats initially near versus far from either boundary, as the former can be relatively coherent in an effect known as edge enhancement or signal localization. We consider DEXSY signals in the case of extended field gradients and identical encodings. Signals were generated via a numerical approach that solves the Bloch-Torrey equation in discrete space and time using matrix operators. We find that in the localization regime, an apparent first-order rate constant of exchange, $k$, can be extracted from DEXSY signals even in this minimal system. The measured $k$ is approximately proportional to $D/L^2$, where $D$ is the diffusivity and $L$ is the domain size. Typically, $k \approx \pi^2 D/L^2$. We attribute this localization-driven exchange to the relaxation of spatial magnetization modes with mixing time, noting that $\pi^2 D/L^2$ is the first non-zero eigenvalue of the Laplacian basis. These results demonstrate that DEXSY and related methods such as filter exchange spectroscopy (FEXSY) may not be specific to genuine barrier permeation.
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Materials Science

Coexistence of ferromagnetism and ferroelectricity in the van der Waals multiferroic CuIn0.2V0.8P2S6

Two-dimensional (2D) van der Waals (vdW) multiferroics have emerged as a promising platform for next-generation multifunctional devices. Although recent studies have demonstrated that artificial heterostructures can combine dual ferroic orders and exhibit strong magnetoelectric coupling, their performance is sometimes limited by poor interface quality and inadequate long-term stability. By contrast, the realization of intrinsic single-phase materials with coexisting ferromagnetism and ferroelectricity remains a longstanding challenge in the field. Here we report the realization of a single-phase 2D vdW multiferroic system, CuIn0.2V0.8P2S6, which exhibits both ferromagnetism and room-temperature ferroelectricity. The intrinsic ferroelectric nature of CuIn0.2V0.8P2S6 was probed using ferroelectric tunnel junctions, which exhibit a large tunneling electroresistance with an ON/OFF ratio of 107 at 295 K. CuIn0.2V0.8P2S6 develops ferromagnetic ordering with the Curie temperature (TC) of 14.6 K, as evidenced by pronounced magnetic hysteresis and a relatively large remanent magnetization. Notably, the appearance of a magnetodielectric response below TC is consistent with the anticipated interplay between the ferromagnetic and ferroelectric orders. These results highlight a promising route toward single-phase van der Waals multiferroics with coexisting ferroic orders.
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All authors Subrata Ghosh, Rosalin Mohanty, Yuwei Sun, Soumi Mondal, Chandan De, Jose G. Jimenez, Weiwei Xie, Cheng Gong, Zhiqiang Mao

Statistical Mechanics

Long-wavelength amplification of an NLS conserved-charge violation in a one-dimensional Gross-Pitaevskii-Poisson field

Can weak self-gravity be treated as a small, generic perturbation of the integrable one-dimensional cubic nonlinear Schrödinger equation? We test this question by following the first nontrivial local NLS charge, $Q_3$. In the Gross-Pitaevskii-Poisson model it obeys the exact identity $\dot Q_3=\kappa F_3$, where $F_3$ is the instantaneous gravitational force on the charge. We quantify the initial violation through the normalized mean-square displacement of $Q_3$. Its curvature coefficient, $A_3={\rm Var}(F_3)/{\rm Var}(Q_3)$, measures the root-mean-square initial speed of the charge in units of the charge's own ensemble width. For a UV-regulated, linearly stable Gaussian initial-data preparation, Wick contraction gives ${\rm Var}(Q_3)=O(L)$ and ${\rm Var}(F_3)=O(L^2)$, hence $A_3=O(L)$. Direct Monte Carlo evaluation of the full nonlinear observables confirms these powers for $16\leq L\leq 512$. The linear growth of $A_3$ means that admitting longer wavelengths makes nominally weak gravity increasingly effective at displacing the NLS charge. Along the Jeans-stable sequence $\kappa_L\propto L^{-2}$, the associated short-time curvature scale is $L^{3/2}$ instead of the $L^2$ benchmark of an infrared-uniform perturbation. This is an equal-time result, not a relaxation-rate or KPZ measurement. The local sound sector contains the Burgers self-coupling required for KPZ, but unscreened gravity also generates a relevant inverse-gradient coupling and, at fixed strength, a Jeans band. A dynamical connection to KPZ therefore requires a projected charge-relaxation calculation and a branch-resolved structure-factor test.
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Materials Science

AI-ready design of realistic 2D materials and interfaces with Mat3ra-2D

Artificial intelligence (AI) and machine learning (ML) models in materials science are predominantly trained on ideal bulk crystals, limiting their transferability to real-world applications where surfaces, interfaces, and defects dominate. We present Mat3ra-2D, an open-source framework for the rapid design of realistic two-dimensional materials and related structures, including slabs and heterogeneous interfaces, with support for disorder and defect-driven complexity. The approach combines: (1) well-defined standards for storing and exchanging materials data with a modular implementation of core concepts and (2) transformation workflows expressed as configuration-builder pipelines that preserve provenance and metadata. We implement typical structure generation tasks, such as constructing orientation-specific slabs or strain-matching interfaces, in reusable Jupyter notebooks that serve as both interactive documentation and templates for reproducible runs. To lower the barrier to adoption, we design the examples to run in any web browser and demonstrate how to incorporate these developments into a web application. Mat3ra-2D enables systematic creation and organization of realistic 2D- and interface-aware datasets for AI/ML-ready applications.
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Materials Science

On a relationship between grain boundary free energy, grain boundary segregation, and grain boundary diffusion

We present a detailed analysis of the universal relationship between grain boundary (GB) free energy and GB self-diffusion coefficient derived by Borisov et al. (1964). This relationship was expressed by a simple equation that was used in many publications to predict GB energies on the basis of experimental diffusion data. Meanwhile, the physical assumptions and approximations underlying the Borisov model are poorly understood. As a result, the Borisov equation was often used outside its intended limits. Here, we re-derive the Borisov equation from ground up, identifying its underlying assumptions, correcting some errors and inconsistencies, and extending the original model to the case of impurity diffusion and diffusion by the interstitialcy and interstitial-dumbbell mechanisms. The meaning of the key assumption of the Borisov model, related to the free energy of the activated complex, is discussed, and ways to test this assumption are proposed.
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Materials Science

Shining light on short-range atomic ordering in semiconductors alloys

The functional properties of semiconductors are typically controlled by tailoring their chemical composition and their state of strain, and by controlling their long-range structural order, including the presence of extended defects such as dislocations. In addition to these approaches, theoretical predictions suggest that short-range order (SRO) of atoms in group-IV semiconductor alloys can modify the bandgap, a defining property of any semiconductor. Herein, a new machine learning enabled, computation-guided methodology for extended X-ray absorption fine structure (EXAFS) analysis of SRO is used to quantify the effects of local atomic order on the bandgap of germanium-tin (GeSn) alloy single crystal nanostructures with well-controlled strain and composition. Correlative analysis of EXAFS and photoluminescence (PL) establishes the relationship between bandgap and the Warren-Cowley short-range order (WC-SRO) parameter of the GeSn alloys. It is further demonstrated that SRO can be tuned over a broad range by post-deposition annealing of the alloy crystals. This work establishes control of SRO as an important design parameter for semiconducting properties and suggests the potential for quantitative measurement and tuning of SRO in other semiconductor alloy systems.
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All authors Anis Attiaoui, Shunda Chen, Joseph C. Woicik, J. Zach Lentz, Liliane M. Vogl, Jarod E. Meyer, Kunal Mukherjee, Andrew Minor, Tianshu Li, Paul C. McIntyre

Materials Science · Cross-listed from physics.chem-ph

Enhancing Spin Coherence of Optically-Addressed Molecular Qubit by Nuclear Spin Hyperpolarization

Optically addressable molecular triplet spins provide a chemically tunable platform for quantum application, but their coherence is often limited by interactions with surrounding spin baths. Here we demonstrate controlled suppression of nuclear-bath-induced decoherence in photoexcited triplet spins of pentacene co-crystallized in high-purity naphthalene single crystals. By hyperpolarizing the proton spin bath through triplet dynamic nuclear polarization (triplet-DNP), magnetic noise generated by the nuclear spins is suppressed, leading to an extension of the electron spin transverse coherence time. Experimentally, we observe a 25% enhancement of the spin-echo decay time with $60\%$ polarization of the proton spin bath. The measured scaling of the spin-echo decay time ($T_2$) with nuclear polarization quantitatively follows the predicted dependence derived from the polarization-controlled nuclear second moment. Both the enhancement and the absolute value of the coherence time are quantitatively reproduced by cluster correlation expansion (CCE) simulations. These results establish nuclear spin hyperpolarization as a general and actively tunable approach to engineering coherence in molecular qubits. This work provides a broadly applicable design framework for high-coherence molecular and solid-state spin systems.
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All authors Boning Li, Patrick Hautle, Duhan Zhang, Liangping Zhu, Ashley Beers, Zeyu Wang, Paola Cappellaro, Tom Wenckebach, Yifan Quan

Materials Science

The Shape of Chocolate: A Topological Perspective on Food Microstructure

We present a computational framework for characterizing the molecular self-organization of cocoa butter (Theobroma cacao) during dark chocolate tempering through the lens of Topological Data Analysis (TDA). A physics-inspired particle simulation models N=100 triglyceride molecules across the full temperature range 15–60 degrees C, spanning all six crystalline polymorphs of cocoa butter (Forms I–VI) as well as the melt and superheating regimes. At each temperature tick, we construct a Vietoris-Rips filtration and compute the persistent homology groups H0 (connected components), H1 (independent cycles), and H2 (3D voids). The resulting persistence diagrams are analyzed via persistent entropy E = -sum_i p_i log2(p_i), where p_i = l_i / sum_j l_j and l_i = death_i - birth_i denotes feature lifetime; essential classes are assigned death = m+1 (m = eps_max) following the standard persistent entropy convention (Rucco 2026, arXiv:2602.09058). Our results demonstrate that Form V (the optimal tempering polymorph, 29.5–34 degrees C) is characterized by a distinctive topological signature: a local minimum in the H0 persistent entropy (E0 = 5.74 +/- 0.04 bits), a pronounced depression in the first Betti number beta_1 (1562 +/- 35), and a global minimum in the H2 entropy (E2 = 12.29 +/- 0.25 bits) reflecting coherent inter-bilayer lamellar cavities. Via Theorem 1 and Corollary 1 of Rucco (2026), persistent entropy is proven to separate the ordered and disordered phases by an asymptotically non-vanishing gap whenever a phase transition induces the creation or destruction of topological mass at macroscopic scales – a condition we verify empirically across all eight cocoa butter regimes. These findings suggest that TDA-based metrics could serve as non-invasive quality indicators for industrial chocolate tempering processes.
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Materials Science · Cross-listed from cs.DB

Electrospinning-Data.org: A FAIR, Structured Knowledge Resource for Nanofiber Fabrication

Electrospinning is a versatile nanofabrication technique whose outcomes emerge from a complex, high-dimensional interplay between solution properties, processing parameters, and environmental conditions. Optimizing this parameter space for targeted fiber morphology is inherently challenging, often driving extensive trial-and-error experimentation and generating vast experimental data across laboratories worldwide. Yet this knowledge remains fragmented and underutilized due to inconsistent reporting and a pervasive bias toward successful outcomes, limiting reproducibility and hindering data-driven research. Here we introduce Electrospinning-Data.org, a FAIR-aligned data aggregation infrastructure that organizes dispersed electrospinning experiments into structured, reusable, and failure-aware scientific records. The platform is built around a unified process-structure-property data model linking experimental inputs, environmental conditions, and nanofiber morphology, annotated through a controlled vocabulary, within a consistent, machine-readable schema. A two-stage moderation pipeline combining automated validation with expert review supports data quality and long-term interoperability. The resulting structured, failure-inclusive corpus provides a framework for data-driven research, including predictive modelling, inverse design of target morphologies, and systematic mapping of instability regimes that would otherwise require extensive trial-and-error experimentation.
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Mesoscale and Nanoscale Physics

Ground-State Selection by Pure Energy Relaxation in Polariton Condensates

We study nonequilibrium mode selection in dissipative exciton-polariton condensates incoherently pumped through an excitonic reservoir in the presence of pure energy relaxation. For a confined system in which a vortex mode is selected at threshold, we show that energy relaxation qualitatively changes the condensation scenario: as the pump increases, the asymptotic state evolves from a vortex condensate to a rotating mixed state and then to a ground-state condensate. Pure energy relaxation thus destabilizes condensation into excited states and promotes ground-state selection.
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Strongly Correlated Electrons

Quantum simulation of interlayer charge ordering in Kagome frustrated-magnet

The interplay between interlayer coupling and quantum fluctuations governs charge ordering and defect dynamics in Kagome systems, yet these parameters are intrinsically entangled in existing Kagome metals and artificial spin-ice platforms, preventing their independent control. Here we realize a bilayer Kagome frustrated-magnet simulator comprising 1,536 connected spins on D-Wave quantum annealer, in which the effective quantum drive, $\Gamma_{\rm eff}$, and interlayer exchange, $J_{\perp}$, are independently programmable. We observe an interlayer-driven transition from ferroelectric to antiferroelectric Ice-II charge order at a critical coupling $(J_\perp/J_1)^*\approx0.04$, a phenomenon absent in single-layer geometries. Monte Carlo calculations show the transition persists in the classical limit, allowing the experimentally observed critical coupling to quantify the quantum renormalization induced by fluctuations. Applying resulting phase diagram to Kagome charge-density-wave materials places KV$_3$Sb$_5$ and RbV$_3$Sb$_5$ deep within the ordered antiferroelectric regime, while locating CsV$_3$Sb$_5$ near the phase boundary, providing a natural explanation for its metastable $2\times2\times4$ stacking order. We further show that restricting charge-correlation measurements to ice-rule configurations resolves a systematic underestimation of ordering in conventional analyses, enabling direct reinterpretation of resonant X-ray, XMCD, STM and anomalous Hall experiments. Finally, we demonstrate that the same charge-sector reorganization framework explains near-degenerate plateau states in the metallic Kagome spin-ice HoAgGe and yields experimentally testable predictions for nanomagnetic, Kagome-metal and van der Waals frustrated systems. These results establish programmable quantum annealers as scalable simulators of emergent charge order and monopole physics in frustrated quantum matter.
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Other Condensed Matter · Cross-listed from hep-th

Higher-spin composites and emergent AdS$_3$ geometry in the $(1+1)$-dimensional Gross-Neveu model

We study the $(1+1)$-dimensional Gross-Neveu (GN) model with $N$ fermion species and derive from it an emergent AdS$_3$ geometry together with the leading entries of a holographic dictionary. We use a Bargmann-Wigner fusion scheme to generate an infinite tower of higher-spin composite fields from fundamental fermions and study their relative dynamics. A key feature is that the competition between spin-0 (chiral) condensation and spin-1 pairing defines the radial coordinate $z$ of the bulk geometry. Local fluctuations of this ratio measured by a comoving derivative generate the AdS$_3$ line element, and the large-$N$ species sum promotes $z$ from a parameter to a genuine bulk dimension. The $SO(2,2)$ bulk isometry group, whose special conformal generators mix $z$ with the boundary GN coordinates, emerges from local symmetries of the condensates. Our construction admits two dual holographic frames related by the $\mathbb{Z}_2$ exchange of the spin-0 and spin-1 condensates, covering complementary halves of the GN phase diagram. Significantly, projection onto the spin-2 sector reproduces the linearized Einstein-Hilbert action with Newton's constant $G_3 = \ell_\mathrm{AdS}/4\pi N^2$. We suggest throughout how the string-theoretic sector of the correspondence may emerge.
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Strongly Correlated Electrons

Berezinskii-Kosterlitz-Thouless Quantum Supercriticality in XXZ Heisenberg Spin Chain

Quantum fluctuations can give rise to a singular quantum critical point (QCP) in the ground state, whose influence extends to finite temperatures, forming a quantum critical regime (QCR). Recently, it has been shown that in the quantum Ising model, the symmetry-breaking, longitudinal field can induce a quantum supercritical regime (QSR) emanating from the QCP, which hosts a universally enhanced quantum supercritical magnetocaloric effect (MCE). In this paper, we show that the QSR also emerges in the spin-1/2 XXZ model, in both the form of Ising and Berezinskii-Kosterlitz-Thouless (BKT) supercriticality. Using ground-state and finite-temperature tensor-network methods, we investigate quantum supercritical phenomena near a BKT QCP. We reveal a quantum supercritical crossover scaling $T \propto h^{2/3}$ and a Grüneisen ratio scaling $\Gamma_h \propto T^{-3/2}$ for the BKT QCP, which differ from the corresponding Ising supercritical scalings. Nevertheless, we find that the scaling function $\phi_{\Gamma}(x)$ of the singular Grüneisen ratio for both BKT and Ising cases can be approximately described by the same expression $\phi_{\Gamma}(x) \approx x/(1+x^2)$. Our work extends the study of quantum supercritical phenomena from the Ising to the XXZ Heisenberg model, thereby revealing the presence of BKT quantum supercriticality and broadening the scope of quantum supercritical physics.
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All authors Haoshun Chen, Enze Lv, Ning Xi, Fei Ye, Wei Li

Mesoscale and Nanoscale Physics

Benzo-bis(imidazole) self-assembled monolayers molecular junctions in meta or para conformation: effects of protonation on the electrical and thermal conductances

We report the thermal conductances of molecular junctions made of self-assembled monolayers of benzo-bis(imidazole) molecules, without side groups or functionalized with two phenylamine side groups. In the two cases, when the molecules are connected to the electrodes by thiol anchoring groups in the meta-position, the thermal conductance is decreased compared to the same molecules connected in the para-position (ca. 16-29 nW/K and ca. 37-40 nW/K, respectively) in agreement with the theoretically predicted phonon interference effect in molecular junctions. Upon protonation, the thermal conductances of the meta-connected molecular junction increase by about 50% (reversible behavior upon deprotonation). The fact that only the thermal conductance of the meta-connected molecular junction is sensitive to the protonation/deprotonation is tentatively related to modifications of the structural organization of the molecules in the monolayer, which modifies the thermal conductance at the molecule/electrode interfaces. The electrical conductance is lower for the meta-connected molecule than for the para-connected one, due to destructive quantum interferences, as expected and reported for other molecular junctions. The conductance further decreases (reversibly) upon protonation. The energy position of the molecular orbital involved in the electron transport is not modified by the protonation and the decrease in current is related to changes in the molecule organization in the monolayer, which modulate the electronic coupling energy at the molecule/electrode interfaces.
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All authors Sergio Gonzalez-Casal, Simon Pascal, Olivier Siri, Dominique Vuillaume

Soft Condensed Matter

Cratering by the oblique impact of a spinning projectile

We investigate the roles of spin and packing fraction on the dynamics of cratering when a solid projectile impacts a granular bed at different incident angles. For that, we carried out DEM (discrete element method) computations in which we varied the magnitude and direction of the projectile spin, the impact velocity, the bed packing fraction, and the incident angle. For a given incident velocity, we found that the projectile can rebound for small angles, or be completely or partially buried for larger angles, and that when buried it can sometimes migrate large horizontal distances depending on the incident angle. We also found that increasing the packing fraction strengthens rebounds, and that the initial spin, depending on its direction and orientation, induces rebound, burying, or transverse deviations. The crater morphology also changes with the varying parameters, acquiring circular, elliptical, goutte-like, tadpole-like, and transitional shapes, correlating well with the projectile behavior. Finally, we propose diagrams organizing and classifying the dynamics observed. Our results shed new light on the different shapes of craters found in nature and the fate of the impacting material.
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Materials Science

Electrically and Magnetically Tunable Charge-Density-Wave Transport in Quasi-2D h-BN/1T-TaS2 Thin-Film Heterostructures

Controlling collective electronic phases in low-dimensional materials is a central challenge for developing technologies based on charge-density waves. Here, we report that perpendicular electric and magnetic fields can be used to tune charge-density-wave transport in the quasi-two-dimensional material 1T-TaS2. Using h-BN-encapsulated thin-film heterostructures with both top-gate and bottom-gate configurations, we find that electrical gating produces a non-monotonic shift in the depinning threshold, a behavior distinct from that of quasi-one-dimensional charge-density-wave systems. We further show that a perpendicular magnetic field increases the threshold voltage for domain depinning and can drive the nearly commensurate-to-incommensurate charge-density-wave phase transition, demonstrating magnetic control over a two-dimensional electron-lattice condensate. The obtained results shed light on mechanisms governing charge-density-wave domain dynamics and reveal combined electrical and magnetic-field control as a strategy for engineering low-power-dissipation devices and electronics for extreme environments.
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All authors Jonas O. Brown, Maedeh Taheri, Nicholas R. Sesing, Tina T. Salguero, Alexander A. Balandin

Mesoscale and Nanoscale Physics · Cross-listed from quant-ph

Birefringent Curvature Control of Surface Plasmons and Collective Emission

We present a generic wave equation for surface plasmon polaritons on any macroscopically curved metal-dielectric interface, with isotropic and anisotropic geometric potentials linear in curvature. Remarkably, the anisotropic birefringence vanishes if the metal-to-dielectric permittivity ratio equals the golden ratio squared, mimicking isotropy at linear order on an actually anisotropic surface, as confirmed by full-wave simulations. Applying our equation to quantum emitters on metallic spheres, we demonstrate a curvature-controlled reshaping of collective decay rates and frequency shifts.
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Materials Science

Solving the inverse problem of X-ray absorption spectroscopy via physics-informed deep learning

Resolving transient atomic configurations in non-crystalline or dynamic environments remains a fundamental bottleneck in the physical sciences. While X-ray absorption spectroscopy (XAS) is a premier probe of local structure, inverting spectra into structural descriptors is a notoriously ill-posed problem due to inherent many-to-one mapping. Here, we present the Spectral Pattern Translator (SPT), a physics-informed deep learning framework that establishes a robust bridge between large-scale theoretical datasets and experimental reality. Our strategy exploits the Fourier duality between spectral energy oscillations and spatial scattering paths to overcome the "simulation-to-experiment" gap. By decomposing spectra into frequency domains, SPT effectively isolates robust structural coordination signals from the destabilizing noise inherent in experimental data. Trained on a massive library of diverse atomic environments, this approach achieves state-of-the-art accuracy in resolving continuous phase transitions in battery cathodes and deciphering local order in amorphous materials. With millisecond-scale latency, SPT removes the primary computational barrier to autonomous materials discovery, establishing a robust, noise-resilient engine for closed-loop robotic chemistry.
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All authors Suyang Zhong, Boying Huang, Pengwei Xu, Fanjie Xu, Yuhao Zhao, Jun Cheng, Fujie Tang, Weinan E, Zhong-Qun Tian

Strongly Correlated Electrons

Cs$_3$V$_9$Te$_{13}$: A Correlated Electron System with Topological Flat Bands

Correlated electron systems with topological flat bands show great promise in exploring exotic quantum phenomena. However, such crystalline materials remain rare. Here we report the discovery of a novel material, Cs$_3$V$_9$Te$_{13}$, which unexpectedly exhibits magnetism and significant electron correlations. The crystal structure features two interpenetrating sets of vanadium triangles that can be linked with an ideal kagome lattice. The physical property measurements demonstrate a cascade of correlated electron phenomena, including quasi-two-dimensional bad metal, non-Fermi-liquid behavior, antiferromagnetic spin-density-wave transition at $T_\mathrm{N}$ = 47 K, possible short-range spin ordering at $\sim$350 K, a large Sommerfeld coefficient of 246 mJ mol-fu$^{-1}$ K$^{-2}$, and pressure-induced quantum criticality. These correlated electron behaviors are associated with the topological flat bands at the Fermi level, the latter of which are generated from the V2 sublattice in terms of a bipartite kagome model. Our findings establish Cs$_3$V$_9$Te$_{13}$ as a brand new correlated matter that synergistically combines flat-band physics and tunable properties.
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All authors Chang-Chao Liu, Ji-Yong Liu, Jing Li, Hua-Xun Li, Jia-Yi Lu, Tong Shi, Qing-Xin Dong, Gen Li, Bo-Sen Wang, Yi Liu, Jin-Guang Cheng, Guang-Han Cao

Superconductivity

Effect of pressure on the superconducting properties of Au substituted PdTe$_2$ with the CdI$_2$-type structure

Transition metal ditellurides with the CdI$_2$-type structure are materials with intriguing superconducting and electronic properties as demonstrated by PdTe$_2$. Gold substituted PdTe$_2$, Au$_x$Pd$_{{\rm 1}-x}$Te$_2$, adopts the CdI$_2$-type structure for a Pd content larger than 43 at.% at room temperature, and in this range enhanced superconductivity with a critical temperature ($T_{\rm c}$) above 4 K has been reported (Kudo \it{et al}., PRB \bf{93}, 140505, 2016). Here we present the effect of pressure on the structural and superconducting properties of Au$_x$Pd$_{{\rm 1}-x}$Te$_2$ for $x=0.15$, 0.25 and 0.35 with $T_{\rm c} =2.7$, 4.1, and 4.6 K at 1 atm, respectively. Synchrotron radiation x-ray diffraction shows that the CdI$_2$-type structure remains stable up to 8 GPa for all three compositions and that they have almost the same volume compressibility. Heat capacity measurements show that Au substituted PdTe$_2$ exhibits type-II superconductivity, that evolves from weak-coupling BCS for $x=0.15$ to intermediate coupling for $x=0.25$ and 0.35. Electrical resistivity measurements up to a pressure of 2.5 GPa reveal that $T_{\rm c}(P)$ for $x=0.25$ and 0.35 has a shallow maximum with $T_{\rm c}^{\rm max}$ is 4.2 and 4.7 K at $P\sim 0.3$ and 0.7 GPa, respectively, whereas a monotonic decrease is observed for $x=0.15$. Using the McMillan equation, with the Debye temperature ${\it \Theta}_{\rm R}$ extracted from the resistance data under pressure as input, we find a smooth variation of $T_{\rm c}$ with the electron-phonon coupling strength $\lambda_{\rm ep}$ spanning the entire pressure and concentration range, from PdTe$_2$ to 35 at.% Au substitution. We conclude superconductivity across the Au$_x$Pd$_{{\rm 1}-x}$Te$_2$ series under pressure is governed by a delicate balance between lattice stiffening and the strength of the electron phonon coupling.
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All authors Ayako Ohmura, Kazuki Ichikawa, Kyohei Tanaka, Takashi Naka, Motoharu Imai, Fumihiro Ishikawa, Takayuki Nakane, Anne de Visser

Statistical Mechanics

Entropy Production Rate in Stochastically Time-evolving Asymmetric Networks

Networks that characterise the interactions between units composing complex systems are typically treated as fixed. Yet, such networks often stochastically evolve over time, shaping the collective behavior of complex systems. To date, we lack a general non-equilibrium thermodynamic treatment of such time-dependent networks. In this Letter, to address this problem, we model fluctuating interactions between units of nonlinear network systems as uncorrelated colored noise (i.e., annealed disorder) with a correlation time. This approach enables us to quantify how the entropy production rate (EPR) depends on both the time-scale and the strength of the disorder. Using dynamical mean field theory, we derive an exact expression for EPR at any transient time that is validated by simulations of the full dynamics and establish a relation between EPR and autocorrelation at stationarity. We find that annealed disorder shifts the transition from the fixed-point to chaos toward a higher variance of the interactions, thereby suppressing chaos but at the cost of greater dissipation.
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Materials Science · Cross-listed from physics.pop-ph

The Structure of Scientific Socialism: Quantum Emergence, Frustration, and the Non-Dual Dialectic

Classical Marxism and the algebra of revolution were formulated within the ontological constraints of 19th-century Newtonian materialism-a world of discrete, predictable, billiard-ball interactions. However, the 20th-century transitions in physics, from Thomas Kuhn's paradigm shifts to Phil Anderson's philosophy of emergence, have dismantled the reductionist foundations of this mechanical worldview. This paper proposes a New Manifesto for Scientific Socialism by synthesizing modern condensed matter physics with the non-dual philosophy of Advaita Vedanta. By examining the concepts of Geometric Frustration and Competing Interactions through the lens of Spin-Glasses and Mott Insulators, we argue that social stasis and synthesis are emergent properties of a universal consciousness field rather than mechanical inevitabilities. We further explore how this quantum-informed dialectic resolves the essential tension between the individual and the collective, echoing the intuitions of Schrodinger and Heisenberg regarding the foundational unity of reality.
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Mesoscale and Nanoscale Physics

Nonreciprocal transverse currents in Rashba metal junctions under out-of-plane Zeeman fields

We study charge transport across a junction between a normal metal and a Rashba metal in the presence of a Zeeman field applied to the spin–orbit coupled region. While an out-of-plane Zeeman field does not generate a transverse response in a homogeneous Rashba system, we show that such a junction exhibits a finite transverse conductivity that is inherently nonreciprocal, i.e., it depends on the direction of the applied bias. We demonstrate that this effect originates from the breaking of the $k_y \to -k_y$ symmetry of the Hamiltonian in the presence of the Zeeman field, which prevents cancellation of transverse current contributions from opposite transverse momenta. We further show that evanescent modes in the spin–orbit coupled region play a crucial role by carrying a finite spin polarization that gives rise to a transverse current localized near the junction. The transverse conductivity exhibits a peak at an energy scale set by the Zeeman field, displays distinct behavior for opposite bias directions, and shows spatial dependence governed by the nature of the contributing modes. We also identify bound states at the junction for attractive barrier strengths, which enhance conductivity when their energies lie near the transport window. Our results reveal a mechanism for nonreciprocal transverse charge transport in Rashba systems without requiring in-plane magnetic fields or ferromagnetic contacts, and should be experimentally accessible in semiconductor heterostructures.
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