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Physics

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Saturday 10 October

Plasma Physics

First achievement of 100 million degree electron temperatures in a spherical torus: the EXL-50U

Guang Yang, Shaodong Song, Songjian Li et al. (+14 more)

Here,we report an ST plasma in which Thomson scattering measures a central electron temperature exceeding 8.6 keV (100 million degrees kelvin) on the EXL-50U spherical torus device.The high-temperature phase is obtained at low density by sequential operation of two 50 GHz ECRH systems: ordinary-mode (O-mode) ECRH3 followed by extraordinary-mode (X-mode) ECRH4. In contrast to neutral-beam-heated high-ion-temperature ST scenarios, the discharge is sustained by ECRH only.
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All authors Guang Yang, Shaodong Song, Songjian Li, Xiaobing Xie, Zhaokun Wang, Xiang Gu, Jia Li, Xianli Huang, Xinchen Jiang, Yupeng Guan, Huicong Ma, Junquan Lin, Dong Guo, Jiaqi Dong, Yunfeng Liang, Yuejiang Shi, the EXL-50U Team

High Energy Physics (Theory)

A critical coupling for the magnetic instability of holographic SU(2) plasmas

Migael Strydom

We show that gravity can remove the linear magnetic instability of a holographic plasma with an $SU(2)$ global symmetry. In the probe limit, charged vector bosons become tachyonic in their lowest Landau level above a critical field and condense into a vortex lattice. In Einstein-$SU(2)$ Yang-Mills theory in AdS$_5$ we include the backreaction of the field exactly, expanding only in the condensate around the D'Hoker-Kraus magnetic brane. The critical field diverges as the coupling $\alpha = \kappa^2/\hat g^2$ approaches $\alpha_\star = 2/3$, above which the normal phase has no linear charged instability at any field or temperature: we show this at zero temperature and establish it numerically at finite temperature. At zero temperature the field cancels from the mass of the lowest Landau level in the brane's AdS$_3 \times \mathbb{R}^2$ throat, and the instability is a violation of the throat's Breitenlohner-Freedman bound. The onset temperature vanishes at $\alpha_\star$ with an essential singularity of Berezinskii-Kosterlitz-Thouless type. For two-derivative Einstein-Yang-Mills duals in $d = 4$, 5 and 6 dimensions the normal phase has a charged instability if and only if $C_J/C_T < 8/(d^2(d+1))$, one tenth in $d = 4$. Above $\alpha_L = 0.372$ the gravitational attraction between vortices makes the uniform lattice unstable and the transition first order, so $B_c$ is only a spinodal; whether a condensed phase survives above $\alpha_\star$ is left open.
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Materials Science

Crossed Electric Spin Generation in Multilayers

Xukun Feng, Wei Du, Jin Cao et al. (+3 more)

We propose a crossed electric spin generation effect in multilayer structures. This effect combines the advantages of in-plane and gate electric fields for manipulating spin, and unveils a nice quantum geometric structure in terms of the underlying hybrid Berry curvatures that are unique to quasi-2D systems and manifest inherent spin-layer-orbital coupling. Combining our theory with first-principles calculations, we predict sizable spin generation in 2D ferromagnetic Fe3GeTe2 and altermagnetic V2Te2O. Our theory opens a new Berry-curvature route for all-electric spin manipulation in 2D materials
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All authors Xukun Feng, Wei Du, Jin Cao, Qian Niu, Shengyuan A. Yang, Cong Xiao

High Energy Physics (Experiment)

Forward decay chain reconstruction with displaced vertices in intense magnetic fields

Sergio Javier Jaimes Elles, Simone Libralon, Fernando Martinez Vidal et al. (+7 more)

Precise reconstruction of particle decay chains is essential for a broad range of analyses in particle physics experiments, particularly those targeting flavour physics and spectroscopy. We present a standalone, modular and extensible decay tree reconstruction framework designed to handle complicated topologies, accounting for tightly constrained particle decays and long-distance trajectory extrapolations through regions of intense and inhomogeneous magnetic field, as well as limited momentum resolution. Implemented in C++, the framework is optimised for configurability and performance. Developed primarily within CERN's LHCb experiment, its focus is on decay chains with vertices located several metres from the LHC proton-proton interaction point, where the dipole magnetic field is maximal and non-uniform. Even so, it remains flexible: it can accommodate these special cases as well as the approximations commonly used in standard decay tree fitting tools, and the geometries of general-purpose collider detectors. Benchmark studies using simulated data demonstrate significant improvements in reconstruction efficiency, invariant mass resolution, and vertex position resolution with respect to existing tools, opening new opportunities for precision measurements and searches involving highly displaced decays.
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All authors Sergio Javier Jaimes Elles, Simone Libralon, Fernando Martinez Vidal, Nicola Neri, Miguel Rebollo de Miguel, Izaac Sanderswood, Volodymyr Svintozelskyi, Giorgia Tonani, Javier Velilla Serna, Ziyi Wang

Quantum Physics

Reducing Trust Cost in Quantum Application Development Using AI

Katsuhiro Endo

Generative AI can be a powerful tool for supporting the design and implementation of quantum applications, whereas the burden of checking whether generated circuits realize the intended computation increases. In this study, we regard this burden of human understanding, checking, and judgment as “trust cost,” and propose a development methodology that integrates AI and formal verification to reduce it. In the proposed development methodology, the implementation is divided into three components: a target mathematical specification, a quantum circuit, and a correspondence theorem and its proof that prove the agreement between the two. This division separates the specifications and theorem statements checked by humans from the theorem proofs entrusted to mechanical checking. As a concrete development example of this proposal, we describe an implementation for the time evolution of a stochastic particle system and its results.
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Plasma Physics

SPIRE: Spin-Resolved Particle-in-Cell with Radiative Corrections for Extreme Laser–Plasma Interactions

Xian-Zhang Wu, Huai-Hang Song, Wei-Min Wang et al. (+1 more)

We present SPIRE, a spin- and photon-polarization-resolved particle-in-cell (PIC) code for self-consistent simulations of laser-plasma interactions in the strong-field quantum electrodynamics (QED) regime. The classical PIC framework combines a Yee-grid finite-difference time-domain Maxwell solver, a relativistic Boris particle pusher, shape-function particle-grid interpolation, Esirkepov charge-conserving current deposition, laser boundary injection, and a relativistic moving window in one, two, and three spatial dimensions. A vectorial Laguerre-Gaussian laser injector based on an angular-spectrum formulation supports tightly focused, nonparaxial optical orbital-angular-momentum modes. The strong-field QED module treats nonlinear Compton scattering and nonlinear Breit-Wheeler pair production as stochastic processes using spin- and polarization-resolved probabilities in the local constant-field approximation. Electron and positron spin evolution includes stochastic transitions, no-emission corrections, and Thomas-Bargmann-Michel-Telegdi precession with a field-dependent anomalous magnetic moment. Photon polarization is represented by the Stokes vector and evolves through nonlinear Compton scattering, pair production, vacuum birefringence, and vacuum dichroism. The implementation is verified with one-, two-, and three-dimensional benchmarks. Classical PIC results are cross-checked against SMILEI, and the spin- and polarization-resolved QED modules reproduce published results for polarized electron generation, vacuum birefringence and dichroism, and dense polarized positron production. These benchmarks verify the coupled classical PIC, strong-field QED, spin, and photon-polarization modules implemented in SPIRE.
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All authors Xian-Zhang Wu, Huai-Hang Song, Wei-Min Wang, Yan-Fei Li

Astrophysics of Galaxies

Multiphase Analysis of (U)LIRG Nuclear Activity (MAUNA). I. Spatially Resolved Optical Emission-Line Diagnostics

Justin A. Kader, Vivian U, Marina Bianchin et al. (+33 more)

We present resolved optical integral-field spectroscopy of the 32 luminous and ultraluminous infrared galaxy systems of the Multiphase Analysis of (U)LIRG Nuclear Activity (MAUNA) sample, drawn from the GOALS survey and selected to have JWST/MIRI medium-resolution spectrometer (MRS) observations. The data set combines new Keck/KCWI observations of 10 systems with archival VLT/MUSE cubes for 22 systems, covering H$\beta$ to [S II] at ~1 arcsecond spatial resolution (~0.9 kpc at the sample median distance). Using the optical [N II]/H$\alpha$ BPT diagram, we find that composite and LINER-like excitation together account for most of the classified area (median fractions 0.44 and 0.26), while Seyfert-like gas covers a median fraction of 0.02 but carries a far larger proportion of the line luminosity where it is present. Both the projected size of the Seyfert-classified region, $R_{\rm Sy}=0.08$-$7.5$ kpc, and its [O III] luminosity increase with the bolometric AGN luminosity, with $R_{\rm Sy}\propto L_{\rm AGN,bol}^{0.54\pm0.18}$, as expected for gas photoionized at a constant ionization parameter. The scatter about the luminosity relation depends on dust opacity: the [O III] luminosity per unit AGN luminosity falls by $1.09\pm0.25$ dex per unit depth of the 9.7 $\mu$m silicate absorption feature (Spearman $\rho=-0.60$, $p=0.001$). Optical excitation diagnostics therefore locate AGN-excited gas reliably but systematically underestimate the luminosity the AGN supplies to the host in the most obscured (U)LIRGs.
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All authors Justin A. Kader, Vivian U, Marina Bianchin, Yiqing Song, George C. Privon, Sabrina Stierwalt, Tanio Diaz-Santos, Lee Armus, Vassilis Charmandaris, Ezequiel Treister, Rosalie McGurk, Hanae Inami, Jeffrey A. Rich, Sean T. Linden, Anne M. Medling, Loreto Barcos-Muñoz, Gabriela Canalizo, Aaron S. Evans, Kirsten L. Larson, Tianmu Gao, Thomas Lai, Laura Lenkic, Jaya Nagarajan-Swenson, Justin Howell, Cristina M. Lofaro, Matthew A. Malkan, María Sánchez-García, Christopher D. Martin, Mateusz Matuszewski, Claire E. Max, Joseph M. Mazzarella, James D. Neill, Nikolaus Z. Prusinski, Raymond Remigio, David Sanders, Jason Surace

Mesoscale and Nanoscale Physics

Magnon Klein paradox

D. Wang

By considering the energy transport of spin wave, we show that, like the electron Klein paradox, there is no magnon Klein paradox for reflectivity. Heuristically, this can be understood according to the fact that, even if the ground state is unstable, any energy-carrying wave cannot have greater-than-one reflectivity off a passive interface, which will violate the conservation of energy. The magnon Klein paradox discussed in the literature is derived from assigning a wrong sign to the transmitted spin wave.
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Atmospheric and Oceanic Physics

Learning native eddy-resolving ocean dynamics outperforms coarse emulation and downscaling

Zilu Liu, Tao Zhang, Hailong Liu et al. (+8 more)

Eddy-resolving ocean simulations are essential for representing mesoscale dynamics that regulate ocean circulation, energy transport, and climate variability. However, they are costly to generate, store, and share. Artificial intelligence (AI) may help, but it remains unclear whether high-resolution ocean fields can be faithfully represented by evolving ocean states at coarse resolution followed by spatial downscaling, or whether dynamical evolution needs to be learned directly from native high-resolution simulations. We show that directly learning dynamical evolution on a 0.1$^\circ$ grid provides a more faithful representation of mesoscale variability than evolving ocean states on a 1$^\circ$ grid followed by downscaling reconstruction. We developed a full-depth 1$^\circ$ emulator and a native 0.1$^\circ$ sea surface temperature (SST) emulator, both of which remained stable over long-term free-running simulations without significant drift, providing reliable baselines for this comparison. Direct learning at 0.1$^\circ$ preserves mesoscale energy, spectral characteristics, and frontal gradients, whereas the coarse-resolution evolution followed by downscaling approach recovers large-scale patterns but fails to reproduce key mesoscale signatures. We show that the learned mesoscale statistics remain consistent across diverse hardware platforms, supporting the reproducibility and portability of AI-based ocean simulations. These results suggest that downscaling of low-resolution large-scale states alone is insufficient to represent ocean mesoscale variability, supporting the need to learn dynamical evolution directly in a high-resolution state space. These findings highlight the continued importance of high-resolution physics ocean models as a foundation for AI-based ocean simulation, providing dynamically resolved training data for physically faithful high-resolution emulators.
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All authors Zilu Liu, Tao Zhang, Hailong Liu, Kai Xu, Qinghui Lin, Maoxue Yu, Jiangfeng Yu, Jingwei Xie, Zhao Jing, Minghua Zhang, Lixin Wu

Optics

Near-focus intensity evolution of spatiotemporal optical vortex pulses and consequences for their nonlinear upconversion

Titouan Gadeyne, Vartika Vishnoi and Thierry Ruchon

Spatiotemporal optical vortex (STOV) laser pulses are attracting attention for their puzzling transverse orbital angular momentum (OAM) and propagation properties, which could determine their future applications. While the characteristic reshaping of their space-time envelope upon diffraction from the focal plane to the far-field is now well-established, the evolution of their intensity as they propagate has not been studied quantitatively, despite growing interest for their use in nonlinear optics and strong-field physics. Here, we explore experimentally and analytically the focusing dynamics of STOVs produced by a pulse shaper, and evidence a substantial longitudinal shift between the coordinate at which a circularly-symmetric STOV forms and that at which the pulse reaches its peak intensity. To illustrate some practical consequences for applications, we experimentally demonstrate how the yield of second-harmonic generation can consequently be maximized several Rayleigh lengths beyond the plane where the circular STOV really occurs. These results signal careful characterization of spatiotemporal pulses as a requisite for nonlinear optical experiments, and pave the way for finer control of complex laser drivers for light-matter interactions.
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Superconductivity

Chemical-Potential-Dependent Superconducting Spectroscopy on Bi2Te3/NbSe2 Heterostructures

Pengyu Hu, Chun Yu Wan, Qiaoyan Yu et al. (+21 more)

High-resolution scanning tunneling spectroscopy performed at dilution refrigerator temperatures was employed to investigate the superconducting properties of topological insulator/superconductor (Bi2Te3/NbSe2) heterostructures. Coherence peaks with inner kinks or inner peaks, deviating from the conventional single s-wave spectral line shape, were observed in both 5 quintuple-layer (5QL) and 7QL Bi2Te3 thin films. Based on the combination of chemical-potential-dependent spectroscopic measurements and model simulations, we conclude that these spectral features arise from contributions of bulk and surface states in Bi2Te3 by selectively proximity-coupled to a single superconducting gap from NbSe2, rather than inheriting the complicated superconductor's order parameter of NbSe2.
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All authors Pengyu Hu, Chun Yu Wan, Qiaoyan Yu, Chen Qian, Yisheng Gu, Xian Du, Xuhui Ning, Tingwen Miao, Shi Chen, Zihao Ma, Hao Yang, Hemian Yi, Weijiong Chen, Xiaoxue Liu, Liang Liu, Dandan Guan, Yaoyi Li, Shiyong Wang, Canhua Liu, Sangen Zhao, Fulin Wang, Junwei Liu, Hao Zheng, Jinfeng Jia

Materials Science

Enhancing Quasi-Two-Dimensional Electronic Structure in Bi2O2Se via Chlorine Substitution

Yong-Zhen Jiang, Qi-Xun Wen, Xiang Xu et al. (+17 more)

Bismuth oxyselenide (Bi2O2Se) has emerged as a leading semiconductor candidate for next-generation electronics and quantum phenomena research. However, its strong ionic interlayer bonding of Se layers fundamentally restricts the full potential of this otherwise promising quasi-two-dimensional (2D) material. In this work, we demonstrate chlorine substitution as an effective strategy to introduce van der Waals gaps and modify the electronic structure of the system. Through comprehensive transport and angle-resolved photoemission spectroscopy (ARPES) measurements on Bi6O6Se2Cl2 single crystal, an optimal Cl-doping compound, we show that the key electronic features, including indirect band gap, high electron mobility, and carrier effective mass, are well preserved, while the 2D character of the system is sufficiently enhanced. First-principles calculations attribute this selective tunability to the unique spatial separation between conductive Bi-O layers and dopant Se/Cl layers, which enables independent optimization of interlayer coupling and intralayer transport. Remarkably, our theoretical calculations combined with experimental observations project a broad bandgap engineering across a wide range (0.8 ~ 3.5 eV) within the Bi2O2Se system. Our findings not only expand the application potential of Bi2O2Se-based materials in optoelectronics, nanoelectronics, and fundamental research but also highlight spatial decoupling as a viable strategy for modifying detailed electronic structure of quasi-2D quantum systems.
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All authors Yong-Zhen Jiang, Qi-Xun Wen, Xiang Xu, Su-Tao Sun, Feng-Fan Ren, Zi-Xuan Zhou, Xing-Yuan You, Yu-Cheng Kan, Zheng Zhang, Jie-Yi Liu, Yu-Zhou Zhao, Zheng-Tai Liu, Mao Ye, Shu-Hua Yao, Jian Zhou, Yan-Bin Chen, Zhong-Kai Liu, Yu-Lin Chen, Yang-Yang Lv, Cheng Chen

Astrophysics of Galaxies

Beyond the Damped Random Walk: Multiband AGN Variability from SDSS to Rubin LSST

Izak Schmidlkofer, Zhirui Hu, Weixiang Yu et al. (+1 more)

The flux variability of Active Galactic Nuclei (AGNs) is commonly modeled using the damped random walk (DRW), but increasingly rich multiband time-domain surveys motivate more flexible stochastic models that characterize variability beyond a single timescale and exploit dependence across bands. Multivariate continuous-time autoregressive moving average (MCARMA) processes extend the multivariate DRW to higher-order stochastic dynamics and provide a matrix-valued power spectral density for characterizing marginal variability and cross-band dependence. In a carefully selected Sloan Digital Sky Survey (SDSS) Stripe~82 sample, higher-order models are selected for 109 of 134 AGNs (81.3%), with substantial rather than marginal support in most objects; convergence diagnostics indicate that this fraction is conservative. The fitted models also reveal strong cross-band dependence that generally decreases with wavelength separation. Motivated by this richer structure, we investigate its recoverability under Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST) observing conditions. Model-order recovery depends strongly on the underlying stochastic behavior as well as source brightness and observing cadence. Recovery is high across many of the simulated settings, but deteriorates when the characteristic features of higher-order variability become difficult to distinguish from the multivariate DRW. Additional simulations show that this loss of distinguishability can persist over a range of underlying variability behaviors. These results show that stochastic structure beyond the multivariate DRW is prevalent in our selected SDSS sample, while its recoverability with LSST depends on both observational conditions and the form of the underlying stochastic variability. The methodology is implemented in the Python package mcarma.
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All authors Izak Schmidlkofer, Zhirui Hu, Weixiang Yu, Hyungsuk Tak

Optics

Maximal Axion Optical Chirality Enabled by Degenerate Quasibound States in the Continuum

Chang-Yin Ji, Chong Wang, Jiafang Li et al. (+1 more)

Axion quasiparticles introduce magnetoelectric coupling in topological materials, yet their optical signatures are intrinsically weak, severely limiting experimental detection and practical exploitation. Here, we demonstrate maximal optical chirality of axion quasiparticles by coupling them with degenerate quasibound states in the continuum (qBICs). By integrating three-dimensional topological insulators (3DTIs) with achiral photonic crystal slabs (PCSs), we reveal that axion quasiparticles induce an effective Zeeman effect that lifts the degeneracy of achiral qBICs in PCSs, splitting them into two nondegenerate high-Q chiral qBICs with maximally opposite chirality. These result in a more than 10^3- and 200-fold increase in the polarization conversion efficiency and Faraday rotation angle, respectively, compared to the intrinsic chiroptical response of bare 3DTI films. Moreover, circular dichroism and nonreciprocal optical responses are revealed as new key signatures for probing axion quasiparticles in 3DTI-PCS coupled systems. Our results provide a definitive route for observing axion quasiparticles and topological physics, while establishing a promising platform for controlling optical polarization, spin, phase, and nonreciprocal responses.
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All authors Chang-Yin Ji, Chong Wang, Jiafang Li, Yugui Yao

Mathematical Physics · Cross-listed from math.AG

Cetraro lectures on integrable systems and moduli spaces of curves

Alexandr Buryak and Paolo Rossi

In these lecture notes we review some constructions and results on the relation between topology of the moduli space of stable curves and integrable systems of evolutionary PDEs.

Quantum Physics

Scalability and performance metrics for boson sampling devices

Dong-Gil Im, Chung-Hyun Lee, Joonsuk Huh et al. (+1 more)

Linear-optical platforms provide a promising route to demonstrate quantum computational advantage, particularly through the boson sampling problem. While a boson sampling system should be large enough to show the quantum advantage, the size of the boson sampling problem is often restricted by experimental constraints. In particular, as a boson sampling system is scaled up, experimental constraints can limit its effective problem size to permit efficient classical simulation. In this paper, we investigate the theoretical scalability bounds for boson sampling systems under practical experimental conditions, including photon loss, mode mismatch, and input state error. We employ non-negativity conditions for phase-space quasiprobability distribution functions to analyze these effects. In addition, we introduce two device-level metrics, the boson sampling score which measures the usable capacity of a given device and the boson sampling volume which provides a common hardware-level benchmark for comparing different platforms and assessing their access to an advantage-relevant problem size regime. Our results provide fundamental insights into the performance of boson sampling systems under realistic experimental conditions and offer practical guidelines for scaling up boson sampling systems.
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All authors Dong-Gil Im, Chung-Hyun Lee, Joonsuk Huh, Yoon-Ho Kim

Materials Science

A Fisher-Geometric Approach to Supercell Pair Distribution Function Refinement

Dawei Wang

Refining atomistic supercells against powder pair distribution functions (PDFs) requires optimizing many coupled atomic coordinates using a much smaller set of radial measurements. Reverse-mode differentiation makes gradients accessible for large systems, but standard first-order optimizers do not explicitly use coupled PDF sensitivities to precondition coordinate updates. We introduce a matrix-free, Fisher-geometric approach that pulls the information metric of the observation likelihood back onto atomic coordinates. The resulting update weights collective displacements according to their PDF response and experimental uncertainty. Under isotropic damping, the update is obtained by solving a damped linear system over $M$ PDF channels, using automatic differentiation to evaluate Jacobian–vector and vector–Jacobian products without constructing the full Jacobian or coordinate curvature matrix. For Gaussian measurement errors, the update recovers classical Levenberg–Marquardt refinement while avoiding dense coordinate-space factorization. The same computational framework accommodates correlated Gaussian errors and robust likelihood-based updates. This approach combines likelihood-aware collective updates with matrix-free backpropagation for direct second-order refinement of large atomistic supercells.
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Soft Condensed Matter

Surface Granular flows: Two Related Examples

Devang V. Khakhar and Ashish V. Orpe

Granular surface flows are common in industrial practice and natural systems, however, theoretical description of such flows is at present incomplete. Two prototype systems involving surface flow are compared: heap formation by pouring at a point and rotating cylinders. Continuum models for analysis of these flows are reviewed, and experimental results for quasi-2d systems are presented. Experimental results in both systems are well described by continuum models.
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Quantum Physics

Exploring Dynamical Quantum Phase Transitions via the Dynamical Phase Accumulated at an Equilibrium Critical Point

Han-Chuan Kou, Peng Li, Zhi-Han Zhang et al. (+1 more)

We investigate dynamical quantum phase transitions (DQPTs) generated by a two-step linear quench with a finite waiting time at the equilibrium critical point. The waiting stage leads to the accumulation of a dynamical phase that depends on the waiting time and directly reflects the critical spectral structure. In the transverse Ising chain, this accumulated phase modifies the critical structure of DQPTs from a single-critical-mode (SCM) regime to a multiple-critical-mode (MCM) regime. We analytically and numerically determine the boundary between the two regimes. Along this boundary, the waiting time approaches a constant in the sudden-quench limit, whereas in the slow-quench limit it follows Kibble–Zurek (KZ) scaling with the quench time. In the SCM regime, the rate function exhibits a conventional linear singularity, $r(t)-r(t^{*})\propto |t-t^{*}|^\alpha$, with the critical exponent $\alpha=1$ near the critical time. At the SCM–MCM boundary, this exponent changes to $\alpha=1/2$, leading to a divergent first derivative of the rate function. Additional discrete parameter lines with $\alpha=1/2$ also appear within the MCM regime in the parameter plane spanned by the waiting and quench times. Our findings establish a direct connection between the accumulated dynamical phase and the critical structure of DQPTs, further supported by an extended Su–Schrieffer–Heeger (SSH) model.
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All authors Han-Chuan Kou, Peng Li, Zhi-Han Zhang, Zhen-Yu Zheng

Instrumentation and Methods for Astrophysics

ELISA: A Bayesian X/$\gamma$-ray Spectral Analysis Toolkit

Wang-Chen Xue, Sheng-Lun Xie, Chao Zheng et al. (+11 more)

Forward-folded X/$\gamma$-ray spectral fitting increasingly benefits from Bayesian workflows to better capture counting statistics, background uncertainties, and complex parameter degeneracies, while fully reproducible end-to-end implementations are still not always straightforward to deploy in routine analyses. We present ELISA (Efficient Library for Spectral Analysis), an open-source Python toolkit that streamlines the full spectral analysis loop for X/$\gamma$-ray astronomy: data loading, model construction, inference, and model validation and comparison. ELISA couples a JAX-accelerated forward model with a unified fitting interface, supporting both rapid optimization and modern Bayesian sampling. Built-in diagnostics make convergence checks and predictive assessment a standard part of the workflow, motivating principled model refinement when needed. Using a spectral fitting example of the Insight-HXMT Crab observation, we find substantial improvements in sampling efficiency compared with XSPEC's default MCMC implementation. ELISA is available at https://github.com/wcxve/elisa and on PyPI at https://pypi.org/project/astro-elisa.
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All authors Wang-Chen Xue, Sheng-Lun Xie, Chao Zheng, Shao-Lin Xiong, Xiao-Bo Li, Yong Chen, Peng Zhang, Yan-Qiu Zhang, Jia-Cong Liu, Chen-Wei Wang, Wen-Jun Tan, Yue Wang, Jin-Peng Zhang, Zheng-Hang Yu

High Energy Astrophysical Phenomena

Magnetar X-ray flares as elementary reconnection events in a self-organized critical magnetosphere

Sheng-Lun Xie, Yi Zhao, Wen-Long Zhang et al. (+3 more)

Magnetar bursts are commonly attributed to magnetic energy release, yet the physically relevant dissipation unit has remained uncertain. Here we argue that this unit is not the burst as conventionally defined, but the short substructures within bursts, namely magnetar X-ray flares (MXFs). Using 789 MXFs from SGR~J1935+2154, we show that their waiting times separate into two components, interpreted as reflecting clustered intra-episode events and longer inter-episode intervals, that their proxy emission measure and temperature exhibit distinct rising and declining trends, and that their energy release scale (ERS) proxy distribution has a high-end slope in the same statistical regime as solar and stellar flares. Combined with the previously measured MXF duration slope, these results identify MXFs as a three-dimensional fractal-diffusive self-organized critical (FD-SOC) system with $\beta_{\rm diff}\simeq2$, implying reconnection avalanches that expand linearly through an active magnetosphere. We infer that magnetar active episodes are global unloading states assembled from many elementary flares. Magnetar X-ray flares are therefore the physically relevant units for magnetar outburst statistics and for connecting magnetar high-energy activity to other impulsive phenomena.
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All authors Sheng-Lun Xie, Yi Zhao, Wen-Long Zhang, Chen-Wei Wang, Yun-Wei Yu, Shao-Lin Xiong

Quantum Physics

Entanglement-Capability-Aware Finite-Bond Circuit Cutting for Distributed Quantum Computing

Weidong Liu, Qingqing Jiang, Yufu Liu et al. (+4 more)

Distributed quantum computing distributes workloads that exceed a single processor's capacity across resource-constrained components. Circuit cutting enables this decomposition, but its effectiveness depends on partition choice. We present SACE, a Simulation-Aware Circuit Partitioning framework with Entanglement-Capability-Aware Screening. EP-Cost screens partitions using a parameter-dependent entanglement-capability proxy and native implementation cost. Under reconstruction constraints, finite-bond refinement selects the candidate that minimizes the worst-subcircuit discrepancy between normalized MPS simulations at bond dimensions $\chi$ and $2\chi$. Across 14 exhaustively enumerated small-scale candidate spaces, EP-Cost-guided genetic algorithm selections attain co-optimal native quasiprobability decomposition (QPD) overhead, with a median within-circuit Spearman correlation of 0.9965 between EP-Cost and QPD overhead. At matched cut counts, EP-Cost reduces QPD overhead by $25.20\times$ and $16.89\times$ for 8- and 9-qubit QFT circuits, respectively, and improves sampled reconstruction. On 12-qubit approximate QFT, deterministic reconstruction reduces Pauli-observable mean absolute error in all six low-bond conditions and total-variation distance in five. With five cuts and 7,776 QPD terms, SACE is best on all four reconstruction metrics in four of six conditions. At 24 qubits, SACE improves exact-local QFT accuracy in all 30 instance-bond-dimension conditions against each EP-Cost-only, Kernighan-Lin, and spectral baseline. The 50-qubit QFT comparisons remain favorable as reference convergence improves. Weighted QAOA circuits provide complementary, more bond-sensitive evidence. Refinement benefits persist across three search methods; larger candidate panels improve the optimized proxy without guaranteeing lower exact-local error.
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All authors Weidong Liu, Qingqing Jiang, Yufu Liu, Ruiqing He, Jiandong Shang, Hengliang Guo, Qiang Chen

Physics and Society

Joint Trust-Distrust Structure Shapes Belief Propagation and Collective Dynamics

Mozhgan Khanjanianpak and Yu-Ru Lin

Belief propagation in social networks depends on how trust and distrust jointly shape interpersonal influence. We develop a network model that treats trust and distrust as distinct but statistically coupled quantities. Their joint values determine the net trust and uncertainty of each relationship, and a neighbor can influence an agent only when both threshold conditions are satisfied. We show that the correlation between trust and distrust reshapes the transition between consensus and fragmentation by changing the availability of influential neighbors. Network connectivity also affects this transition, whereas degree heterogeneity has a more limited effect when networks have comparable mean degree. Moreover, the availability of influential neighbors alone does not determine the final consensus: correlations between relational properties and network degree can select agents with different degree compositions, altering the direction and magnitude of collective belief. Finally, we introduce a comfort index that quantifies the expected availability of influential neighbors and analytically links the joint trust-distrust structure to collective dynamics. Our results establish a mechanistic connection between relational structure, effective social influence, and emergent collective belief states.
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Soft Condensed Matter

Optoelectronically Enabled Simultaneous and Decoupled Navigation and Selective Pairing of Electrically Driven Janus Particles for Multi-Agent Microrobotics

Srikanta Debata, Ido Rachbuch and Gilad Yossifon

Self-propelled Janus particles are promising active agents for microscale manipulation and microrobotic applications. However, when powered by a global external energy source, such as an electric, magnetic, or optical field, all particles respond simultaneously, preventing their independent and concurrent control. Achieving parallel, decoupled control without continuous particle-specific feedback, while preserving intrinsic self-propulsion, remains a significant challenge. Here, we present an optoelectronic (OE) strategy for simultaneously and independently controlling electrically driven, self-propelled metallo-dielectric Janus particles (JPs) using spatially programmable virtual electrodes. These electrodes are generated by projecting a single predefined illumination pattern from a digital micromirror device onto a photoconductive surface. The resulting confinement landscape enables multiple JPs to follow distinct trajectories without continuous monitoring, feedback, or pattern reconfiguration. We demonstrate controlled pairing of JPs with passive polystyrene particles and biological cells. For automated multi-agent operation, an image-based assignment framework identifies optimal agent-target pairs, excludes intersecting trajectories, and generates a single composite pattern for simultaneous, selective pair formation without real-time updating. Finally, we demonstrate independent manipulation of multiple magnetically rolling JPs under a globally applied magnetic field. Overall, this programmable open-loop strategy provides a versatile framework for multi-agent microrobotic manipulation, with potential applications in in-vitro micromanipulation and microfluidic systems.
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Atomic Physics

Interpretation of chirality imprinted on photoelectron momentum spectra by three-dimensional light fields

Junxin Yuan, Yuhong Li, Fei Li et al. (+9 more)

Synthetic three-dimensional (3D) light fields provide a new route to imprinting chirality on achiral matter through light–matter interaction. Although previous work has numerically demonstrated that chirality can be imprinted on the photoelectron momentum spectrum of atoms, a transparent analytical physical picture that links the structure of the driving field to the chirality of the spectrum is still an open question. Here, using frequency-domain theory based on nonperturbative quantum electrodynamics (QED), we demonstrate that this chirality originates from coherence between adjacent quantum transition channels. We further find that a symmetry transformation introduces into the coherence term a symmetry-breaking phase shift ($\Phi_{\mathrm{SBPS}}$), which can be tuned by varying the laser-field parameters to preserve or break the corresponding symmetry in the spectrum. Once all such symmetries are broken, the momentum spectrum becomes chiral. In particular, for the noncollinear two-color 3D light field considered here, the spectrum is chiral for even $f=\omega_2/\omega_1$ and achiral for odd $f$. Our results provide a microscopic interpretation of chirality imprinting and establish a framework for predicting and controlling chiral electron wave packets with synthetic 3D light fields.
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All authors Junxin Yuan, Yuhong Li, Fei Li, Jinkai Zhang, Shiyang Zhong, Hao Teng, Yujun Yang, Yingchun Guo, Zhiyi Wei, Jing Chen, Xiaojun Liu, Bingbing Wang

Strongly Correlated Electrons

Exotic metallic phase in a heterotic Kondo lattice: violation of Luttinger's theorem and absence of Kondo gap

Hanting Zhong, Shuxiang Yang, Chao Cao et al. (+3 more)

Fermi surface transformation accompanied by quantum phase transition is widely observed in correlated electron systems including heavy fermion materials and van der Waals quantum heterostructures. The unified Anderson lattice description for this phenomenon suggests that their interacting ground states in the case of electron half filling always destabilize the metallic phase in the strong Kondo-coupling regime. We examine this issue within the paramagnetic phase of a Kondo lattice system with a heterotic layered structure. In the weak Kondo-coupling regime, the system exhibits a fractional Dirac liquid involving the massless or massive Dirac fermions and a charge neutral spinon Fermi surface. In the strong Kondo-coupling regime, the spinons hybridize with the Dirac fermions resulting in an intermediate nearly-flat hybridizing band together with the conduction and valence heavy fermion bands, yielding a large electric Fermi surface. Absence of the Kondo gap between these bands is observed depending on the stacking configurations of the layered structure. In particular, the system remains metallic even at the exact half filling in this regime and Luttinger's theorem is violated across the critical point. Implications of these results on the van der Waals quantum heterostructures are briefly discussed.
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All authors Hanting Zhong, Shuxiang Yang, Chao Cao, Xiao-Yong Feng, Jianhui Dai, Hai-Qing Lin

Statistical Mechanics · Cross-listed from cs.LG

Active Neural Matter: A Finite-Window Response Framework for Physical Systems and Distributed AI Workflows

Tianchi Chen and Shihua Yu

Physical systems and distributed AI workflows can retain past information, receive delayed feedback and combine conflicting signals. These features pose a common modeling problem: determining what information about past interactions a state must retain to account for future responses. Active Neural Matter (ANM) addresses this problem through a finite-window response framework. Forward analysis uses each system's dynamics to predict state and output responses to perturbations, separating propagation from output sensitivity. Inverse analysis tests whether a candidate state retains enough information for these responses. With the system and future inputs or interaction rules fixed, distinguishable responses from histories assigned the same state identify distinctions the representation must preserve. Their distributional separation gives a lower bound on the worst-case error of approximating behavior from that state. Uncertainty bounds distinguish rejection, support within a fixed tolerance on tested comparisons, and unresolved cases. Delayed-consensus simulations check analytical predictions of response amplitude and phase over a narrow range of delays; flocking illustrates dependence on the chosen observable. An exact delayed-return construction establishes a sufficient state for a specified program. The AI studies identify distinctions in interaction history and evidence order that a representation must preserve to reproduce observed response distributions. Tests on new histories in a controlled feedback task provide bounded support for a state specified by the task instructions; the instructed rule predicts every observed action. ANM connects response prediction to measurable information requirements, separating behavioral fidelity from task correctness and initial-state adequacy from a closed evolution law for that state.
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Accelerator Physics

Learn the Dynamics, Enforce the Physics: Generative Latent Operators for High-Dimensional Beam Evolution

Haohan Zou, Alexander Scheinker and Yuanyuan Shi

Particle-in-cell (PIC) simulation is indispensable for modeling beam dynamics in particle accelerators, but its computational cost limits many-query workflows, such as configuration exploration, virtual diagnostics, and controller design. We introduce GLOBE, a physics-constrained Generative Latent Operator for Beam Evolution, modeling the nonlinear, control-dependent, multiscale evolution of 3D beam–field dynamics covering $10^7$ spatial cells. GLOBE compresses beam–field states into a compact latent space and factors their evolution into two components. A control-conditioned neural operator learns the dominant dynamics, while an amplitude-normalized generative model captures the residual distribution, recovering fine-scale structures and conditional variations. GLOBE enforces field constraints by regime-specific, parameter-free operators: a Poisson solve reconstructs the electric field in the electrostatic regime, and a spectral projection imposes Gauss's law and a divergence-free magnetic field in the electromagnetic regime. On two high-resolution 3D particle-accelerator benchmarks, bunched-beam transport and plasma-wakefield acceleration, GLOBE lowers relative-$L_2$ error by 9% and 13%, low-frequency spectral error by 69% and 51%, and mid-frequency spectral error by 54% and 20% relative to the strongest baseline (DPOT), satisfies field constraints, and reduces hours of PIC simulation to a minute per rollout.
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Quantum Physics

Sample-Size Scalability and Representation Sensitivity of Quantum Machine Learning Models for Higgs Boson Event Classification

Shiksha Bhardwaj and Ankhi Roy

Quantum machine learning offers new approaches to multivariate event classification in high-energy physics, but its performance relative to optimized classical methods remains uncertain under limited training data and restricted quantum resources. We investigate the sample-size scalability and representation sensitivity of a quantum support vector machine and a variational quantum classifier for Higgs-boson signal–background discrimination using simulated events from the ATLAS Higgs Machine Learning Challenge. The models are trained on balanced subsets ranging from 250 to 4000 events and evaluated on held-out samples preserving the original class distribution. Principal component analysis (PCA) and autoencoder (AE) representations are examined to reduce the input dimensionality and quantum-resource requirements. Four optimized classical classifiers are used as benchmarks under a common preprocessing, validation, and evaluation protocol. We assess training-sample scalability in classical and quantum classifiers using a four-component PCA representation and examine representation sensitivity through a secondary matched-event comparison of four- and eight-component PCA representations. Within the evaluated Higgs-boson classification setting, the QSVM showed stronger performance than the VQC at larger training sample sizes, while remaining below the best-performing classical classifiers.
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High Energy Astrophysical Phenomena

Impact of Decay-Chain Feeding by Long-Lived Heavy Nuclei on Nuclear Cosmochronology

Qiu-Hong Chen, Meng-Hua Chen, Xianlin Yang et al. (+1 more)

Nuclear cosmochronology provides an independent method for determining the ages of astrophysical objects without relying on Galactic chemical evolution models. Long-lived radioactive actinides synthesized via the rapid neutron-capture process ($r$-process) particularly thorium and uranium serve as ideal chronometric nuclei. However, predicting the initial abundances of these nuclei and their subsequent long-term evolution remains a major source of uncertainty in nuclear cosmochronology. In this work, we investigate the impact of decay-chain feeding from long-lived progenitor nuclei on nuclear cosmochronology and estimate the corresponding age corrections. We develop a self-consistent radioactive decay network that includes all relevant decay pathways and couple it to $r$-process nucleosynthesis calculations. By tracking the long-term evolution of $r$-process nucleosynthesis based on neutron star merger trajectories, the dominant long-lived nuclei shaping the evolution of the chronometric elements Th and U are identified as $^{232}$Th, $^{235}$U, $^{236}$U, $^{238}$U, and $^{244}$Pu. It is found that delayed feeding substantially modifies the long-term evolution of actinides particularly for $^{232}$Th, which receives significant late-time contributions from heavier progenitor nuclei such as $^{244}$Pu and $^{236}$U. As a consequence, the U/Th and Th/X chronometers exhibit significant sensitivity to delayed feeding from the progenitor nuclei $^{244}$Pu and $^{236}$U, with age corrections reaching $\sim5$~Gyr. These results suggest that decay-chain feeding from long-lived progenitor nuclei plays a crucial role in nuclear cosmochronology and should be properly accounted for in age determinations based on actinide chronometers.
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All authors Qiu-Hong Chen, Meng-Hua Chen, Xianlin Yang, En-Wei Liang