Strongly Correlated Electrons
Field-Induced Up-Up-Down State and Frustrated Magnetism in a Non-Kramers Triangular Antiferromagnet
Zhaoyi Li, Qinchen Duan, Bo Wen et al. (+2 more)
A previously unreported triangular
lattice (TL) antiferromagnet, TmZnGaO4, was synthesized as single
crystals, and its
crystal structure,
magnetic susceptibilities, and specific heat were reported. Its
crystal structure is isomorphic to that of the transverse-field Ising antiferromagnet TmMgGaO4, with Tm3+ ions located in the TLs, separated by a nonmagnetic
bilayer composed mainly of Ga3+ and Zn2+ ions. The
magnetic susceptibilities indicate the dominating
antiferromagnetic interactions. The magnetization curves (M-H) exhibit strong easy-c-axis anisotropy, with a clear one-third
magnetic plateau emerging, consistent with a field-induced up-up-down
spin configuration. Instead of forming a conventional long-range
magnetic order, the system exhibits two broad anomalies at 0.11 K and 2.81 K in zero-field specific heat measurements, highlighting the persistence of strong
spin fluctuations and the potential for exotic
quantum spin states. The above results reveal its future interest in exploring exotic
quantum spin states in TmZnGaO4.
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All authors Zhaoyi Li, Qinchen Duan, Bo Wen, Ruidan Zhong, Shu Guo
Optics
Event-based Scheimpflug LiDAR for Ultra-Fast Laser-Scanned Rangefinding
Nathan Meraz, Alisha Whitehead, Suet Ying Chan et al. (+3 more)
Frame-based ranging systems are constrained by frame rate and provide no intrinsic mechanism for background rejection, limiting utility in high-throughput or cluttered environments. We present eSCHORTY, a Scheimpflug
LiDAR integrating an event-based sensor with a modulated continuous-wave line
laser to enable dense 3D point clouds, generated from over one million megaevents per second. We demonstrate that
laser modulation provides a trade-off between event-space feature detection and localization, and that logarithmic event encoding suppresses the reflectance-induced centroid artifact demonstrated in intensity-based ranging. Reconstructions of natural scenes confirm spatially coherent depth recovery, with the Scheimpflug geometry supporting adaptation from millimeter- to kilometer-scale applications.
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All authors Nathan Meraz, Alisha Whitehead, Suet Ying Chan, Ronan Taneja, Gabriella Mayrend, Joseph L. Greene
Strongly Correlated Electrons
Thermal Signatures of the Slater-Mott Crossover in the Hubbard Model: From Double Occupancy to Antiferromagnetic Correlation Length
Mingzhong Lu, Yu-Feng Song, Youjin Deng et al. (+1 more)
The interaction-driven crossover from a Slater
insulator to a Mott
insulator in the Néel-ordered ground state of the Hubbard model is a fundamental paradigm of strongly correlated electrons, yet its quantitative characterization has remained elusive. Here we establish a clear and experimentally accessible thermal criterion for this crossover via the sign change of the temperature derivative of double occupancy, $(\partial D/\partial T)_U$, near zero temperature. In the Slater regime, $(\partial D/\partial T)_U>0$ reflects the major role of charge fluctuations; in the Mott regime, the anomalous $(\partial D/\partial T)_U<0$, a manifestation of the Pomeranchuk effect, signals the dominance of low-energy
spin superexchange physics. Using exact diagonalization and numerically exact
quantum Monte Carlo simulations, we demonstrate that this criterion determines the crossover boundary at $U_{\rm cross}/t=4.0(2)$ for the half-filled two-dimensional Hubbard model. Furthermore, we obtain a consistent boundary independently from the maximum in the
antiferromagnetic correlation length, which also arises from the superexchange physics. These two thermal signatures are theoretically unified through the local minimum of thermal
entropy versus interaction $U$ at low temperatures. Our results offer a direct, measurable, and physically intuitive framework to identify the Slater-Mott crossover in optical
lattice experiments.
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All authors Mingzhong Lu, Yu-Feng Song, Youjin Deng, Yuan-Yao He
Mathematical Physics · Cross-listed from math.PR
Quasisymmetric rigidity of the Brownian sphere
Jason Miller and Yi Tian
The Brownian sphere, also known as the Brownian map, is a canonical random metric measure space homeomorphic to the two-dimensional sphere $\mathbf S^2$. It can be interpreted as the uniform measure on surfaces homeomorphic to $\mathbf S^2$, in the sense that it arises as the scaling limit of many natural models of random planar maps chosen uniformly from a given class. It is also equivalent to the $\sqrt{8/3}$-Liouville
quantum gravity sphere. We prove that the Brownian sphere is quasisymmetrically rigid, meaning that, almost surely, it has no nontrivial quasisymmetric
automorphisms. We also show that two independent Brownian spheres are almost surely not quasisymmetrically equivalent. Our argument also gives a new proof that the conformal structure of the Brownian sphere is almost surely determined by its metric structure.
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Quantum Physics
Inherent flux crosstalk and coupler-driven single-qubit gates in superconducting circuits
Balázs Gulácsi and Guido Burkard
Crosstalk refers to unwanted
qubit addressing. This is particularly detrimental when scaling up
quantum information systems because unintended interactions limit their overall performance. For superconducting
qubits, tunable couplings and frequency tunability achieved through externally applied
magnetic fluxes enable high-fidelity entangling gates; however, they also introduce crosstalk through unintended flux coupling. In this work, we investigate the impact of time-dependent external
magnetic fluxes in quantized
circuits on superconducting
qubit couplings. We find that non-trivial cross-voltage driving emerges between capacitively linked
qubits when the
magnetic flux threading the SQUID loop of a
qubit varies in time, in a manner analogous to Faraday's law of induction. Crucially, we show that this effect enables fast single
qubit control through the coupler element in standard tunable-coupler architectures, potentially eliminating the need for individual microwave $XY$ control lines.
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High Energy Astrophysical Phenomena
The link between obscured accretion and mildly relativistic precessing jets
Rob Fender and Sara Motta
We have recently shown evidence that the most relativistic jets (with Lorentz factor >2) from
stellar-mass black holes in X-ray binary systems may be locked to a fixed axis, likely the
spin axis of the black hole. Slower, mildly relativistic jets (with velocities typically ~ 0.3c) are often seen to precess and can be associated with both
neutron stars and black holes. In this paper we demonstrate an additional clear link between highly obscured systems and these lower-velocity, precessing jets. We speculate that this link may be due to mass-loading of the jets close to their launch sites, since these obscured systems are likely to be examples of (sometimes persistent, other times transient) super-Eddington
accretion. The fastest relativistic jets are now seen to be both locked to a fixed direction, likely the black hole
spin axis, and to be launched in low-density environments, while jets launched in dense environments are generally slower and very likely to precess.
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High Energy Physics (Experiment)
Understanding Energy Dependent Hadronic Calorimeter Response from a Machine Learning Perspective
Shuai-Chun Wang, Huang-Ran Shen, Wan-Bing He et al. (+4 more)
To meet the precision requirements of future high-energy physics experiments, improving the energy resolution of hadronic calorimeters remains a critical challenge. This work presents a systematic investigation of hadronic energy reconstruction using machine learning, highlighting the roles of various signal channels, including scintillation light, Cherenkov light, charged particles, and the full three-dimensional
topology of hadronic showers in the energy range up to 10 GeV. Throughout this study, detector effects are not taken into account. Under these conditions, the intrinsic resolution of hadronic showers reaches approximately $(10.8\pm0.3)\% / \sqrt{E/GeV}$ when all signal channels and the full 3D shower information are fully utilized. Compared with the traditional signal-summing approach, machine-learning-based reconstruction can significantly improve energy resolution, even under a limited sampling fraction of 10%, enhancing it from $(57.6\pm3.7)\%/\sqrt{E/GeV}$ to $(34.1\pm2.8)\%/\sqrt{E/GeV}$. These results highlight the critical importance of both multi-channel information and detailed spatial shower features in hadronic energy reconstruction, and demonstrate the substantial potential of combining high-granularity and dual-readout calorimeter designs with machine-learning-based reconstruction techniques for future experiments.
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All authors Shuai-Chun Wang, Huang-Ran Shen, Wan-Bing He, Wei-Hu Ma, Peng-Jie Li, De-Qing Fang, Yu-Gang Ma
Chaotic Dynamics
Random Matrix Theory for Chaotic Wave Scattering and Transport
Yan V. Fyodorov and Dmitry V. Savin
We review random
matrix approaches to chaotic wave scattering and transport in open systems. Starting from the effective non-Hermitian
Hamiltonian formulation, we discuss the scattering
matrix, reaction
matrix, time delays, and complex resonances as complementary probes of open chaotic dynamics. We emphasize universal statistics governed by
symmetry, openness, and channel coupling. Topics include the maximum-
entropy description of fixed-energy scattering and its applications to
quantum transport, energy correlations, resonance and eigenfunction statistics, and selected wave-chaotic phenomena induced by finite absorption. The focus throughout is on non-perturbative methods and universal structures underlying open
quantum and wave chaotic systems.
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Soft Condensed Matter · Cross-listed from q-bio.BM
A kinetic model of shear-induced rupture of short dsDNA
Ayman Hussein and Ralf Bundschuh
Force-induced dissociation of short double-stranded DNA (dsDNA) is central to single-molecule biophysics and DNA nanotechnology, yet a physically grounded kinetic description of shear-induced rupture for finite-length constructs remains lacking. Here we develop a master equation framework built on a force-dependent nucleation-zipper pathway with single-base transitions, enabling direct calculation of dissociation rates and transition state distances over a broad force range. Applied to a DNA-gold nanoparticle-DNA construct under constant shear force, the model accurately reproduces the experimental room-temperature data in the covered force regime and provides a unified interpretation of prior measurements on similarly sheared duplexes across all force regimes. A central result is that the three-dimensional helical geometry of dsDNA is essential for correctly defining the end to end distance under shear in the rod-like
polymer model of short dsDNA. We further show that the extracted transition state distances are robust to variations in ssDNA
polymer parameters within the experimentally relevant regime. Finally, we analyze the temperature dependence of the transition state distance and discuss how our framework captures globally-heated rupture while identifying the additional complications introduced by localized plasmonic heating in gold nanoparticle-coupled constructs. These results provide a predictive kinetic foundation for interpreting force-rupture experiments and for designing force- and temperature-actuated DNA nanostructures.
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Instrumentation and Detectors
Feasibility demonstration of continuous signal-based neutron noise measurements by experiments and simulations
Máté István Boros, Máté Szieberth, Gergely Klujber et al. (+4 more)
Neutron noise methods are used to determine kinetic parameters such as the
prompt neutron decay constant, but traditional pulse-counting suffers from dead-time and pile-up at high detection rates. Recent theory shows that analysing the continuous detector current can avoid these limitations if pulse-shape effects are properly treated. This work presents a feasibility study of continuous-signal
neutron noise analysis based on simulations and experiments performed at two research reactors. The
stochastic model of the detector current is applied to derive Rossi- and Feynman-type formulations, and pulse-shape distortions are mitigated using detector pairs or by deconvolving the average pulse-shape through inverse
Fourier and Wiener filtering. Simulations demonstrate accurate $\alpha$-parameter estimation at count rates where pulse-counting becomes unusable, and enable evaluation of significantly higher $\alpha$ values. Measurements at KUCA and BME TR confirm that continuous and deconvolved signals provide unbiased results despite dead-time and electronic artifacts, establishing the method as a practical alternative for high-rate reactor noise diagnostics.
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All authors Máté István Boros, Máté Szieberth, Gergely Klujber, Imre Pázsit, István Barth, Yasunori Kitamura, Tsuyoshi Misawa
Adaptation and Self-Organizing Systems
Complexity synchronization as a diagnostic and control principle for adaptive systems
Korosh Mahmoodi, Scott E. Kerick, Piotr J. Franaszczuk et al. (+3 more)
Adaptive systems can exhibit similar levels of performance while relying on fundamentally different internal modes of coordination. Standard metrics such as average cooperation or payoff indicate whether a system succeeds, but do not reveal how coordination is organized across interacting components or which adaptive variables should be targeted when performance fails. Here we propose complexity synchronization (CS), the synchronization of evolving temporal complexity across coupled variables, as a diagnostic and intervention guiding principle for adaptive systems. We test this idea in an adaptive multi
agent system composed of Selfish
Algorithm agents interacting in a reduced Predator Prey model with a Prisoners Dilemma like payoff structure. Temporal complexity is quantified using sliding window modified
diffusion entropy analysis (MDEA) and detrended fluctuation analysis (DFA). CS is defined as the correlation between the resulting time dependent scaling exponents. In the high-interaction regime, MDEA-based CS increases with cooperative performance, whereas DFA based CS captures a distinct persistence dominated coordination mode. Our results show that CS can reveal functionally relevant subsystems and provide a principled basis for targeted repair. More broadly, CS offers a general diagnostic and engineering framework for understanding and controlling coordination in biological, social, human machine, and other adaptive systems.
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All authors Korosh Mahmoodi, Scott E. Kerick, Piotr J. Franaszczuk, David L. Boothe, Paolo Grigolini, Bruce J. West
Quantum Physics
Genuine Multipartite Nonlocality for Arbitrary Input: Maximal Randomness Generation and Robust Self-Testing
Rajdeep Paul, Ranendu Adhikary and Alok Kumar Pan
Bell nonlocality provides the foundation for device-independent (DI) certification of
quantum devices. We introduce a Bell inequality capable of identifying genuine multipartite nonlocality (GMNL) in an arbitrary m-partite scenario with an arbitrary odd number of measurements per party. Since the multi-setting nature of this inequality precludes the use of Jordan's Lemma, we construct an analytical sum-of-squares (SOS) decomposition to obtain the optimal
quantum violation without assuming any bound on the
Hilbert space dimension. This, in turn, enables self-testing of the shared entangled state and the corresponding measurement observables, up to local isometries, whose existence we confirm using a swap-based certification scheme. In addition, we show that our framework enables the extraction of maximal global DI randomness (m bits) at the optimal
quantum violation, thereby exceeding previous limitations in the GMNL regime. Finally, we demonstrate that the architecture of our inequality yields improved robustness to noise as the number of measurement settings grows, ensuring experimental feasibility.
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Computational Physics · Cross-listed from cs.CE
A Constrained Natural-Language Interface for Variational Multi-Physics Finite Element Simulations in FEniCS
Nilay Upadhyay and Wesley F. Reinhart
Large
language models can reduce the manual effort required to set up finite element simulations, but they introduce reliability risks when generated solver code lies on the critical path. We present a constrained natural-
language interface for multi-physics finite element analysis in which the LLM is limited to front-end tasks: parsing
prompts into structured JSON, generating Gmsh code only for non-catalog geometries, and using retry feedback for those stages. It never writes FEniCS solver templates, derives weak forms, or writes the numerical solver core. A deterministic dispatcher maps the validated specification to five human-written FEniCS/UFL templates: linear elasticity, hyperelasticity, elastoplasticity, thermo-mechanical coupling, and phase-field fracture. We validate this deterministic template layer against analytical solutions and published 2D/3D
benchmarks. Smooth cases reach sub-percent agreement on adequate meshes, while harder nonlinear cases reach the 2-5 percent range. We also evaluate the LLM-facing front end directly. In a 15-
prompt parser
benchmark, first-pass valid parses were obtained for 9 cases, and all remaining cases were repaired after retry, giving a final valid parse rate of 100.0 percent, 100.0 percent problem-class accuracy, and 97.1 percent field-extraction accuracy. In a 10-case custom-geometry
benchmark routed through the real LLM-to-Gmsh path, first-pass and final success were both 90.0 percent, with one unrecovered invalid-geometry failure. These results show that the parser and constrained
prompt/validation design are effective on these
benchmarks. As an end-to-end demonstration, the system generates and analyzes a 3D elastoplastic L-bracket with a fillet and bolt hole from one natural-
language prompt. The contribution is a measured architecture for natural-
language-driven variational simulation, not open-ended autonomous code generation.
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High Energy Astrophysical Phenomena
Time lags as proxy of spectral evolution in gamma-ray bursts
C. Maraventano, F. Daigne, R. Mochkovitch et al. (+3 more)
Positive lags in gamma-ray bursts (GRBs), where hard
photons anticipate softer ones, provide a unique window into the temporal
evolution of their
prompt emission. Negative lags, when hard
photons are delayed, are instead more enigmatic to interpret. Disentangling the effects that produce both kinds of lags is critical for identifying the physical mechanisms at work in the
prompt and early afterglow phases of GRBs. We investigate the potential of time lags for distinguishing different emission components at different energy bands. Using data from the
Fermi Gamma-ray Burst Monitor (GBM) and the LAT Low Energy(LLE) technique, we perform a time-resolved joint spectral analysis in the range 10 keV-100 MeV for two exceptionally bright bursts, GRB 160625B and GRB 190114C. Time lags between the lowest-energy band (10-100 keV) and progressively higher-energy bands up to 30-100 MeV were computed across their distinct emission episodes via the cross-correlation function. For GRB 160625B, the spectra are described by a single component with clear hard-to-soft
evolution, and the time lags are always positive. Analysis of the high-energy exponential cutoff, likely originating above the photosphere, yields bulk Lorentz factor estimates of $\Gamma \sim 120-250$. GRB 190114C exhibits negative lags in the 30-100 MeV band, coinciding with a delayed high-energy powerlaw component that dominates the LLE range after ~2.5 s. Comparison with multi-wavelength observations shows some compatibility with the early afterglow, though its origin remains open, leaving room for external shocks or internal dissipation. Time lags are effective diagnostic tools for the spectral
evolution of GRBs: positive lags trace the softening of the
prompt emission, whereas negative lags indicate the appearance of a new, independent high-energy spectral component.
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All authors C. Maraventano, F. Daigne, R. Mochkovitch, L. Nava, G. Ghirlanda, T. Di Salvo
High Energy Physics (Theory)
Spacetime from Operator Algebras
Vyshnav Mohan and Larus Thorlacius
Under suitable assumptions,
geometric objects such as the spacetime metric and
curvature tensor can be reconstructed from the
algebra of operators of quantized matter fields in the limit of vanishing Newton's constant. In this framework, the full non-linear Einstein equations can be expressed in the
language of operator
algebras, extending Jacobson's derivation without invoking the area law for Bekenstein-Hawking
entropy. These assumptions can then be used as a criterion for determining whether the semiclassical limit of a given
quantum theory admits an emergent gravitational description. Going in the other direction, the discrete spectrum of a
holographic theory at finite N can be modelled by adding non-perturbative corrections to semiclassical operator
algebras. The type III von Neumann
algebra that arises in the vanishing Newton's constant limit can be enlarged by adjoining its modular
Hamiltonian. A random
matrix theory completion of this enlarged
algebra, followed by ensemble averaging, results in a type I von Neumann
algebra whose minimal projectors approximate those of the underlying microstates. In the case of an eternal black hole, the dimension of the type I
algebra equals the Bekenstein-Hawking
entropy with universal logarithmic corrections. The complexity of probe operators in the boundary theory provides a diagnostic of the validity of the corresponding bulk semiclassical effective field theory.
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Fluid Dynamics
Topological origin of flow distributions in disordered porous media
Jose Arnal, Guillem Sole-Mari and Tomás Aquino
We investigate steady Stokes flow through porous media composed of two-dimensional disordered arrays of circular obstacles. We develop a theory for the statistics of flow rates based on a pore-network model that captures local flow correlations. We show that the flow rate distribution across the ensemble of pore bodies follows a Gamma distribution, and that the flow rate distribution through pore throats is fully determined in terms of it. Furthermore, this Gamma distribution can be directly linked to simple geometrical properties such as the coefficient of variation of pore throat widths, rendering the model parameterisable from minimal medium information. The resulting predictions agree closely with computational fluid dynamics simulations and show markedly better agreement than prior mean-field models that neglect local flow-rate correlations, clarifying how local splitting and merging shape flow in disordered porous networks.
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Disordered Systems and Neural Networks
Local density of states distribution and multifractal eigenvectors of weighted random networks via the cavity approach
Joseph W. Baron and Tim Rogers
We study the local density of states (LDoS) distribution of a general class of weighted Erdős-Rényi graphs. Using the cavity method, we obtain a good approximation to the full LDoS distribution and compact expressions for its power-law tails, which we show to have exponent $3$ in the extended phase. We deduce that the eigenvectors in the continuous part of the spectrum are extended but (weakly) multifractal, and we extract expressions for the associated fractal dimensions and the singularity spectrum. We also demonstrate that the inverse participation ratio in this multifractal phase exhibits an unusual logarithmic scaling with system size, which is neither fully-extended nor localised by the usual definitions. Finally, we verify that some
symmetry properties (derived from the non-linear sigma model), which have been shown to hold for many systems exhibiting multifractality, also hold in our case, both for the LDoS distribution and the singularity spectrum.
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Materials Science
Degeneracy and trajectory control of spin eigenmodes excited by fs-optical pulses in a nearly compensated ferrimagnet
G. Yu. Levkin, D. M. Krichevsky, N. A. Gusev et al. (+4 more)
We investigate optically excited
spin dynamics in a uniaxial ferrimagnet near the magnetization compensation point under a
magnetic field applied along the
magnetic anisotropy axis. Experiment and numerical modeling reveal an unusual regime where the frequencies of two
spin eigenmodes approach each other and become highly field sensitive. The modes, corresponding to opposite rotations of the Neel vector, simultaneously reverse their handedness at a critical field where their frequencies become degenerate. At this point, the two-frequency precessional dynamics collapses into a linear oscillations directed along the inverse-Faraday-effect excitation induced by a single pump pulse. We further show that a double-pulse excitation scheme enables control of the
spin trajectory. These results uncover an unconventional dynamical regime in ferrimagnets and establish new opportunities for manipulating
spin motion in magnonic systems and devices.
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All authors G. Yu. Levkin, D. M. Krichevsky, N. A. Gusev, A. K. Zvezdin, S. N. Polulyakh, V. I. Belotelov, D. O. Ignatyeva
General Relativity and Quantum Cosmology
Convex foliations and trapped submanifolds
Gustavo Dotti
The
conjecture that compact trapped submanifolds (CTMs) of any codimension greater than one cannot intersect the domain of outer communications of a black hole is tested in symmetrically collapsing spacetimes of $n+1$ dimensions, $n \geq 2$, and on the entire Kerr-Newman sub-extreme family. The results provide evidence to the idea that CTMs of lower dimension, such as trapped loops, should be ragarded as black hole signatures.
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Computational Physics · Cross-listed from cs.CE
Non-linear mechanical field reconstruction coupling recurrent neural networks with physics-informed graph neural networks
Manuel Ricardo Guevara Garban, Yves Chemisky, Étienne Prulière et al. (+3 more)
Reconstructing local stress fields in heterogeneous microstructures under non-linear, history-dependent loading remains a major computational bottleneck in multi-scale simulations. We propose a coupled LSTM-GNN framework that links the temporal and spatial aspects of local stress field reconstruction. A Long Short-Term
Memory network encodes macroscopic stress-strain sequences into a compact hidden state that captures the path-dependent constitutive response, while a physics-informed Graph Neural Network reconstructs the spatially-resolved stress field at each time step. We introduce a relative weighting strategy with linear warm-up to balance the data-driven reconstruction loss and a discrete divergence-based
equilibrium penalty. This resolves the scale mismatch that prevents fixed-weight formulations from converging in the elasto-plastic regime. The model is trained on 10,000 non-proportional loading paths applied to a periodic plate-with-a-hole microstructure and von Mises elasto-plasticity. The model achieves three orders of magnitude speedup over finite element simulations and generalizes to loading sequences twice the training length, with 1.9% cumulative error. Because the graph relies on mesh connectivity instead of the specific element type, one trained surrogate can be applied directly without retraining to meshes with different element types and to both coarser and finer resolutions, while in all cases reproducing the high-fidelity quad-element FE field used during training. Indeed, the message passing characteristics inherent to GNN and MeshGraphNet architecture render the model mesh-agnostic. Analysis of the LSTM hidden states suggests a low-dimensional structure related to the internal state variables of the constitutive model.
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All authors Manuel Ricardo Guevara Garban, Yves Chemisky, Étienne Prulière, Michaël Clément, Martin Abendroth, Björn Kiefer
Optics
A single-step lithography process for reconfigurable SiN photonics with TiN heaters and Al interconnects
Leonardo Limongi, Rachele Favaretto, Lorenzo Baldessarini et al. (+6 more)
Thermo-optic phase shifters are key building blocks in Silicon and Silicon Nitride-based reconfigurable photonic integrated
circuits. They enable manipulating the phase of an optical signal by means of electrically-driven heating of an optical waveguide. Conventional fabrication schemes typically require dedicated lithographic steps to separately define the resistive heaters, the current transmission lines, and the electrical contact pads. This increases the process complexity and slows the standard complementary metal-
oxide-
semiconductor (CMOS) fabrication flows. In this work, we present a single-step lithographic process for the realization of Titanium Nitride thermo-optic phase shifters and Aluminum interconnects integrated on a Silicon Nitride photonic platform. A detailed electro-optical characterization, performed on two platforms operating at 810 nm and 1550 nm, revealed $\pi$-shift powers of 92 $\pm$ 2 mW and 120 $\pm$ 10 mW, respectively. Alongside, modulation bandwidths of 8.5 $\pm$ 0.3 kHz and 3.83 $\pm$ 0.03 kHz were extracted from combined frequency- and time-domain analyses. Our results demonstrate that the proposed single-step lithographic metal definition process represents a robust, viable and cost-efficient route towards CMOS-compatible reconfigurable Silicon Nitride photonics.
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All authors Leonardo Limongi, Rachele Favaretto, Lorenzo Baldessarini, Martino Bernard, Yong Kwon, Gioele Piccoli, Alina Samusenko, Georg Pucker, Mher Ghulinyan
Medical Physics
Flow-Mediated Regulation of Pathogen Survival in the Human Stomach
Sharun Kuhar, Jung-Hee Seo and Rajat Mittal
Foodborne diseases remain a major public-health burden, and the gastric acid barrier serves as the body's primary chemical defense against ingested microbes. Yet experimentally investigating pathogen survival within this environment is highly challenging. Although recent computational stomach models have provided insights into gastric disorders, none have coupled fluid flow, acid transport, and pathogen population kinetics in a realistic stomach to assess gastric acid barrier function. Here, we develop an imaging-based stomach model that tracks 10,000 massless particles representing pathogen colonies ingested with a
liquid meal as they are advected through a dynamic, spatially heterogeneous pH field. The model incorporates acid secretion, peristaltic mixing, and gastric tone-driven emptying. Using this framework, we quantify how hypomotility and altered gastric tone influence pathogen survival. Motility emerges as the dominant factor governing pathogen fate. The hypomotile stomach exhibits weaker mixing, retaining nearly 50% of the initial pathogen population alive 6 minutes after ingestion, compared with less than 30% in healthy cases. It also produces broader acid-dose distributions and more heterogeneous survival outcomes. Counterintuitively, among healthy-motility cases, increased gastric tone delivers the highest concentration of viable pathogens into the duodenum, revealing a trade-off between transport and acid-mediated inactivation. These findings demonstrate that conventional metrics such as average pH or gastric emptying rate are insufficient for assessing gastric sterilization. Instead, the present flow-transport-kinetics framework provides new mechanistic insights into pathogen survival and gastric infection risk.
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Materials Science · Cross-listed from eess.IV
Low-Dose 3D Bonding Mapping Through "Soft" Core-Loss EELS Tomography and Unsupervised Deep Learning
Mario Pelaez-Fernandez, Daniel del-Pozo-Bueno, Adrien Teurtrie et al. (+10 more)
Resolving the 3D chemical configuration of beam-sensitive nanomaterials at high spatial resolution remains a persistent frontier in scanning transmission electron microscopy (STEM). The main limitation lies in the trade-off between high electron dose required for analytical signals and the large number of projections needed for tomographic reconstruction. Here, we achieve dose-efficient 3D bonding mapping of FeO/Fe$_3$O$_4$ core-shell nanocubes with high resolution via electron energy loss spectroscopy (EELS). Our approach relies on two developments. First, a standardless "soft" core-loss EELS methodology exploiting Fe-M$_{2,3}$ edges provides ${\sim}50\times$ higher dose efficiency than conventional Fe-L$_{2,3}$ edges, using the latter only as a source of FeO and Fe$_3$O$_4$ standards. Second, we introduce multi-channel deep image prior with total variation regularization (DIPm-TV), an unsupervised method for spectroscopic
tomography that jointly reconstructs multiple channels by exploiting spatial correlations under sparse-view and low-dose conditions. Using simulated
datasets, high-quality reconstructions are obtained from as few as nine projections over $-70^\circ$ to $+70^\circ$, without HAADF-STEM signal or
symmetry constraints. Applied to FeO/Fe$_3$O$_4$ nanocubes, Fe-M$_{2,3}$ EELS maps show improved SNR and spatial resolution, revealing a thin outer FeO shell surrounding the magnetite shell. DIPm-TV yields ${\sim}1$ nm isotropic resolution oxidation-state volumes preserving cubic morphology, recovering the outer FeO shell, and revealing a small internal void, features not accessible with conventional reconstruction methods. This work establishes a pathway for low-dose 2D and 3D analytical mapping of beam-sensitive materials using shallow core-loss edges, enabling orders-of-magnitude dose reduction while maintaining spectral fidelity and reliable 3D information.
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All authors Mario Pelaez-Fernandez, Daniel del-Pozo-Bueno, Adrien Teurtrie, Serge Brosset, Maya Marinova, Phillipe Ciuciu, Marta Estrader, German Salazar-Alvarez, Francesca Peiró, Raul Arenal, Sonia Estradé, Zineb Saghi, Francisco De la Peña
Earth and Planetary Astrophysics
First detection of HDO ice in a protoplanetary disk
Alexey Potapov, Piyush Kalambkar, Jeroen Bouwman et al. (+4 more)
Protoplanetary disks are the birthplace of
planets and planetary systems. Investigating the molecular inventory of disks is key to linking the chemical
evolution of the interstellar medium and the makeup of
planets and their atmospheres. In particular, tracing the history of the deuterium enrichment of water along the journey from interstellar clouds through protoplanetary disks to planetary systems provides critical insights into the chemical inheritance. We aim to investigate the chemical composition of ices in protoplanetary disks; specifically, the presence of HDO ice that ought to be present, but has not been detected in disks thus far. We analyzed JWST/NIRSpec observations of the 132-1832 edge-on disk located in the Orion Nebula Cluster using the ENIIGMA fitting tool and unique laboratory data. We report on the first detections of HDO ice in a protoplanetary disk. The estimated upper limit for the HDO/H$_2$O ratio for 132-1832 is much higher, compared to HDO/H$_2$O ratios obtained for chondrites, comets, and embedded young
stellar objects. In the disk ices, beyond HDO, we detected H$_2$O, CO$_2$, $^{13}$CO$_2$, CO, OCN$^-$, and OCS, species, whose presence has also been detected in other disks. The HDO ice detection may point to the efficient ice processing in the disk and confirm the findings of laboratory experiments on deuterated ices.
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All authors Alexey Potapov, Piyush Kalambkar, Jeroen Bouwman, Christiaan Boersma, Hiroshi Terada, Will R. Rocha, Hendrik Linz
General Physics
Belief in thermodynamics has provoked false thermodynamics of superconductors
A.V. Nikulov
Belief in thermodynamics has forced superconductivity experts to forget basics of thermodynamics due to a contradiction of superconductivity phenomena to laws of thermodynamics. Because of this belief no one drew reader's
attention during many years that the conventional theory of superconductivity contradicts to the second law of thermodynamics. The common belief that the superconducting transition occurs when the free energy of the superconducting state becomes less than of the normal state has provoked a false claim that a power source of a solenoid creates the energy of magnetization rather than of
magnetic field. The authors of only a few books on superconductivity, mostly future Nobel prize winners, did not follow this false claim. No one for many years has noticed that the equality of free energies at the superconducting transition in the critical
magnetic field cannot be obtained without contradicting the second law of thermodynamics. The Meissner effect violates the second law of thermodynamics because of the negative surplus work performed in the closed Gorter cycle. The desire to avoid contradiction of superconductivity phenomena with the second law of thermodynamics provoked the false thermodynamics of
superconductors, contradicting the law of conservation of energy.
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Biological Physics
Spontaneous polarization for protrusion-driven cell crawling
Pierre Recho
We propose a minimal one-dimensional continuum model for the spontaneous initiation of protrusion-driven
cell crawling on a rigid substrate. The
cell cytoskeleton is represented as a viscous actin meshwork that turns over in the bulk and polymerizes at two moving
cell edges.
Symmetry breaking arises from the feedback between
cell motion, an external chemical regulator of actin nucleation, and actin polymerization at the
cell fronts. When the
cell moves, the regulator becomes polarized around the moving boundaries, thereby imposing different actin nucleation densities at the two edges. This generates unequal protrusive rates, which in turn reinforce motion and sustain the chemical polarization. Above a critical protrusive activity, the static symmetric state loses stability and the system undergoes a bifurcation toward a motile polarized state. Depending on how the external cue controls actin nucleation, the transition can be either supercritical or subcritical, leading in the latter case to coexistence between static and motile states. Using parameter values appropriate for keratocyte
cells, the model predicts crawling speeds of the correct order of magnitude and actin-density profiles that are qualitatively similar to experimental observations, including asymmetric edge-localized density peaks. These results identify a generic mechanism by which external biochemical regulation of actin nucleation can trigger spontaneous motility along a one-dimensional track without requiring molecular motors, specific adhesion dynamics, deformable substrates, or pre-existing polarity.
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Quantum Physics · Cross-listed from cs.CV
Schmidt Decomposition-Based Methods for Efficient Quantum Image Encoding
Ana-Maria Pangeva, Yassine Ferhi, Alexander Geng et al. (+3 more)
In
quantum image processing, a fundamental step is encoding classical image data into
quantum states. This can be achieved using methods such as Flexible Representation of
Quantum Images (FRQI),
Quantum Probability Image Encoding (QPIE), and Novel Enhanced
Quantum Representation (NEQR). However, on real
quantum hardware, these encodings can quickly lead to
circuits with many gates, large
circuit depth, and high
qubit usage, which is a problem for Noisy Intermediate-Scale
Quantum (NISQ) devices. In this work, we investigate whether low-rank state approximation, formulated via Schmidt decomposition, can help reduce this complexity. The method keeps only the most significant parts of a
quantum state's
entanglement structure, making state preparation more efficient while preserving most of the image information. We compare the three encoding techniques in their original form and with low-rank approximation, evaluating metrics such as
circuit depth, CNOT count, MSE, and visual quality of reconstructed images. The results reveal meaningful trade-offs between accuracy and resource efficiency, with the FRQI model achieving a 97 percent reduction in
circuit depth while maintaining a near-perfect reconstruction (MSE of about 0.27). This demonstrates the potential of low-rank techniques for advancing practical
quantum image processing on near-term hardware.
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All authors Ana-Maria Pangeva, Yassine Ferhi, Alexander Geng, Andreas Weinmann, Desislava Ivanova, Ali Moghiseh
Quantum Physics
Quantum Colorings of Spheres
Olivier Lalonde
Cameron, Montanaro, Newman, Severini and Winter gave a construction which shows that, for $n \in \{2,4,8\}$, any graph $G$ which admits a real $n$-dimensional orthogonal representation is quantumly $n$-colorable. This result can be recast as the statement that the real sphere $S^{n-1}$ is quantumly $n$-colorable for these values of $n$. We investigate possible extensions of their construction. We first show that their hypothesis that the orthogonal representation be real-valued is required by proving that there is no analogue of this for the complex spheres, which all have
quantum chromatic number strictly bigger than the dimension except in two dimensions. We also provide candidate finitary witnesses of this and show for the first time that the real and complex orthogonal ranks are distinct as a byproduct. For the real case, we show that if $S^{n-1}$ is quantumly $n$-colorable, then either $n=2$ or $n$ is a multiple of 4, and show that the converse holds whenever a Hadamard
matrix of order $n$ exists. Hence, assuming the Hadamard
conjecture, this completely classifies the dimensions to which the CMNSW construction can be extended. Our method of proof involves showing the equivalence between the existence of such a construction and the existence of a maximal code space for Clifford-algebraic errors given a clean ancilla, and we believe that the representation-theoretic techniques we use for tackling the latter problem could be of independent interest. It also follows from this equivalence that $S^{n-1}$ admits a rank-one
quantum $n$-coloring if and only if $n \in \{2,4,8\}$, thereby settling a
conjecture of Zeng and Zhang, as does the fact that for all $m \geq 1$, there exists a catalytic zero-error remote state preparation protocol for real $m$-
qubit states with $m$ bits of communication and which consumes $m$ ebits.
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Instrumentation and Methods for Astrophysics · Cross-listed from cs.LG
When Do Autoregressive Sequence Models Forecast Physical Wavefields? A Controlled Study on Synthetic Seismograms
Waleed Esmail, Stuart Russell, Jana Klinge et al. (+2 more)
Long-horizon autoregressive
forecasting of oscillatory physical signals, such as seismograms, gravitational-wave strain, and similar wavefields is limited by error accumulation: as a causal model is fed its own outputs over hundreds of steps, small per-step errors compound into phase drift that pointwise metrics fail to detect. We ask when such rollout stays stable, using synthetic three-component seismograms as a physically structured testbed and the SeismoGPT autoregressive forecaster as the model under study. Through controlled architecture ablations evaluated on free rollout with paired significance tests, we isolate the contribution of each design choice. Multi-
token prediction is the dominant stabilizer, accounting for almost the entire improvement over a single-
token baseline ($+0.042$ median NCC); a horizon-
embedding hybrid prediction head and a cross-horizon STFT-magnitude coherence loss each add a small but consistent further gain. Performance depends sharply on a context-ratio threshold near one, roughly the full P-S interval of observed signal, below which rollout generalization collapses. The dominant residual failure is a polarity inversion: a magnitude-based spectral loss reduces its incidence but, by construction, cannot penalize an inverted segment once it occurs, identifying phase-aware objectives as the natural next step. We frame this as a controlled study of rollout stability on oscillatory wavefields, not a
benchmark of
forecasting architectures.
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All authors Waleed Esmail, Stuart Russell, Jana Klinge, Alexander Kappes, Christine Thomas
High Energy Physics (Phenomenology)
Hidden Flavor Geometry and Yukawa Structure from Hidden Coordinates
Petr Baron
We investigate a harmonic interpretation of the hidden
flavor coordinates (Q,G,C) previously introduced in a low-rank ternary description of the
fermion mass spectrum. The generation coordinate is associated with the odd harmonic mode sequence n_G = (1,3,5), allowing the
fermion mass ansatz to be rewritten in a compact harmonic form. The corresponding logarithmic spectrum reveals an additive structure in which the hidden coordinates contribute directly to the observed mass hierarchy. We argue that the projected quantity L = QG + C, which organizes the
fermion masses, does not uniquely characterize a
fermion state. This motivates the introduction of the full hidden-coordinate vector X = (Q,G,C) and a
geometric interpretation of
flavor based on coordinate separations and antisymmetric invariants defined within the hidden-coordinate space. The harmonic framework further suggests a possible extension beyond the
fermion sector. Combining the fermionic harmonic modes generates the bosonic sequence n_B = (2,4,6,8,10), which exhibits a suggestive correspondence with the electroweak and
Higgs scales. Although the resulting framework remains exploratory, it suggests that
fermion masses,
flavor structure, and bosonic states may reflect different aspects of a common hidden harmonic organization.
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