Materials Science
Evaluating a 4B open-weights local LLM for agentic DFT workflows: a literature reproducibility audit
Shambhu Bhandari Sharma
Agentic workflows in materials science relying on hosted commercial models face severe reproducibility, economic, and data-
privacy constraints. To explore fully local agentic science, this work evaluates an open-weights Qwen3:4B model executing an autonomous scientific pipeline across varying hardware constraints. Applied to pentagonal two-dimensional materials, the system extracts parameters from unstructured text, translates them into density functional theory (DFT) inputs, and drives simulations to convergence under a strict neurosymbolic architecture where
agents propose and deterministic code disposes. The workflow is guarded by verbatim text grounding and multi-pass inference unions to counteract hardware-induced structural collapse. Evaluated against 201 expert judgements, the extractor achieves 95.7% precision (95% CI 90.3-98.1%) and 67.3% recall (59.8-74.0%), ensuring extracted parameters are strictly factual. However, precision identifying absent parameters does not exceed 47.0%, establishing that the measured omission rate constitutes a loose upper bound on true literature incompleteness. Across three hardware configurations, complete GPU residency governs extraction quality more fundamentally than weight or cache precision, raising Matthews correlation from 0.414 to 0.530 at fixed quantisation and to 0.560 with an unquantised cache. A corpus-scale audit indicates only 19 (33.3%) of the 57 studies are reproducible in principle, reporting every method parameter needed to re-initialise the calculation. Driven to convergence, the workflow reproduces published
lattice constants with a mean absolute relative error of 2.3% where the relaxed structure retains its prototype, establishing that lightweight open-weights models can reliably drive autonomous agentic workflows when bounded by deterministic code gates.
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Physics and Society
ButterMamba: Butterworth-Enhanced Spatial-Temporal Mamba for Efficient Traffic Flow Prediction
Limiao Zhang, Yuhui Lu, Jie Gao et al. (+3 more)
Accurate traffic flow prediction is fundamental to intelligent transportation systems, playing a pivotal role in urban mobility optimization and smart city development. While Graph Neural Networks (GNNs) integrated with time series
forecasting have emerged as promising solutions, two critical limitations persist: (1) the quadratic complexity of
attention-based architectures hinders real-time deployment in large-scale networks, and (2) high-frequency noise in sensor data significantly degrades prediction reliability. These challenges are particularly acute in metropolitan scenarios where both computational efficiency and noise robustness are paramount. To address these limitations, we introduce ButterMamba, a novel and efficient framework based on State Space Models (SSMs). ButterMamba consists of two key components: (1) a Butterworth Spectral Filtering module that preprocesses the data by removing high-frequency noise, allowing the model to focus on significant underlying trends, and (2) a Spatial-Temporal State Mixer that uses a parallel Mamba architecture to efficiently capture both long-range temporal dependencies and complex spatial correlations across the road network. By decoupling noise filtering from spatial-temporal modeling, ButterMamba achieves superior predictive accuracy with linear computational complexity. Extensive experiments on three public
datasets demonstrate that ButterMamba not only outperforms existing state-of-the-art models in terms of prediction accuracy but also considerably reduces training time and
memory usage.
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All authors Limiao Zhang, Yuhui Lu, Jie Gao, Hao Jiang, Haiping Ma, Xingyi Zhang
Plasma Physics
Generation of Isolated Collimated Polarized $\gamma$-ray Beams via Spatiotemporal Optical Vortex Modulation
Xinyu Xie, Fengyu Sun, Huai-Hang Song et al. (+2 more)
Attosecond, collimated, bright, polarized $\gamma$-ray sources are in high demand across
nuclear physics, astrophysics, and high-energy physics. However, realizing attosecond duration, high collimation, high brilliance, and high polarization simultaneously within a single isolated source remains an outstanding challenge, owing to the inherent trade-offs between beam trapping and radiative dynamics. Here, we propose a novel scheme to generate an isolated, collimated, high-brilliance, polarized attosecond $\gamma$-ray beam from conventional solid foils irradiated by a linearly polarized spatiotemporal optical
vortex (STOV)
laser pulse accessible in Lab. Three-dimensional
spin-resolved particle-in-
cell simulations reveal that this relativistic-intensity STOV pulse can trap and accelerate electrons at its spatiotemporal singularity, producing a compact isolated electron bunch. This electron bunch subsequently undergoes head-on collision with the reflected
laser pulse, which generates isolated $\gamma$-ray beams through nonlinear Compton scattering. With a peak intensity of $7\times10^{21}$ W/cm$^2$, we observe an isolated collimated ($\sim1.5^{\circ}$) $\gamma$-ray beam with an average linear polarization of $>60\%$ and a duration of $\sim$500 attoseconds. This approach is feasible with current or upcoming
laser facilities and robust against variations in
laser and target parameters, highlighting the capability of spatiotemporal structured light field modulation to address outstanding problems in
plasma physics.
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All authors Xinyu Xie, Fengyu Sun, Huai-Hang Song, Wei-Min Wang, Wenpeng Wang
Solar and Stellar Astrophysics
Origin of small-scale evaporation flows deep in the chromosphere during a solar flare
L. P. Chitta, H. N. Smitha, F. A. Iglesias et al. (+29 more)
Flares are caused by an abrupt release of
magnetic energy in the
solar atmosphere.
Plasma heated to well over 10 MK filling the post-
flare corona originates from a rapid heating and ablation of the cooler chromospheric material. This chromospheric evaporation is thought to be facilitated primarily by nonthermal electrons impinging on to the lower atmosphere. Questions on when and where in the chromosphere these upflows originate, however, are not fully resolved. Here we report on unprecedented high-resolution observations of an M-class
flare recorded by the Sunrise Ultraviolet Spectropolarimeter and Imager on board the balloon-borne SUNRISE observatory, that reveal highly structured upflows on spatial scales of ~100 km originating deep in the chromosphere. The flows even precede the onset of nonthermal electrons by about 10 minutes and last through the impulsive phase of the
flare. Our observations shed new light on the lower atmospheric heating and mass circulation in
flares that are challenging to reconcile with the standard
solar flare model.
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All authors L. P. Chitta, H. N. Smitha, F. A. Iglesias, T. L. Riethmüller, A. Feller, W. Chen, A. Lagg, A. Gandorfer, J. Hölken, S. K. Solanki, J. C. del Toro Iniesta, Y. Katsukawa, P. Bernasconi, T. Berkefeld, A. Álvarez-Herrero, M. Kubo, D. Orozco Suárez, B. Grauf, M. Carpenter, A. Bell, Valentín Martínez Pillet, F. J. Bailén, J. Blanco Rodríguez, J. Sebastián Castellanos Durán, E. Harnes, R. T. Ishikawa, Y. Kawabata, T. Matsumoto, T. Oba, A. L. Siu-Tapia, H. Strecker, D. Vukadinović
Instrumentation and Detectors
Toward Ionization Cluster Size Measurements with a Compact Nanodosimeter
Victor Merza, Aleksandr Bancer, Vladimir Bashkirov et al. (+8 more)
Nanodosimetry aims to provide measurable quantities related to the nanoscopic particle track structure, which determines the biological effectiveness of radiation. While simulated nanodosimetry has already demonstrated its potential for radiation treatment planning, the experimental realization of practical nanodosimetric detectors is still in its early stages. In this work, a nanodosimetric prototype operated with low-pressure gas was developed to count ionizations in a nanometer-equivalent sensitive gas volume. Its performance was evaluated experimentally with alpha beams from an Am-241 source in 1 mbar propane gas. The results support the further development of this compact nanodosimeter class, with potential applications in particle therapy, radiation protection, and space radiation dosimetry.
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All authors Victor Merza, Aleksandr Bancer, Vladimir Bashkirov, Ana Belchior, Beata Brzozowska, Piotr Gasik, Jaroslaw Grzyb, Khaled Katmeh, Marcin Pietrzak, Antoni Ruciński, Reinhard Schulte
Mathematical Physics
A Morse-Family Integrator for Hamilton–Jacobi Dynamics Across Caustics
F. Jiménez Alburquerque, M. Leok, C. Sardón et al. (+1 more)
We develop a
geometric framework for implicit discrete
Hamiltonian systems based on discrete Morse families, Lagrangian relations, and discrete analogues of Tulczyjew's triple. The main idea is to regard the Lagrangian submanifold defining the discrete dynamics, rather than an explicit
symplectic evolution map, as the fundamental
geometric object. This viewpoint naturally accommodates implicit, constrained, and degenerate discrete systems. Within this framework, we formulate a Type–II discrete Hamilton–Jacobi theory in terms of the propagation of Lagrangian submanifolds between consecutive discrete steps. When these submanifolds are locally represented by exact one-forms $dW_k$ and $dW_{k+1}$, the resulting equations provide a discrete Hamilton–Jacobi relation between consecutive generating functions. More generally, when the projection onto configuration space becomes singular and a single-valued generating function ceases to exist, we show that the
evolution can be described by the composition of Type–II discrete dynamics with Morse families. This yields a generating family for the propagated Lagrangian submanifold without requiring the dynamics to be represented as a graph. As an application, we consider the propagation of optical wavefronts through fold caustics. A Type–II discrete
Hamiltonian yields a
symplectic ray integrator, while a Morse family represents the multivalued wavefront near the caustic. Their composition provides a discrete propagation rule for the complete Lagrangian
manifold across the singularity. In this way, the same
geometric construction simultaneously provides a discrete
Hamiltonian integrator and a regular representation of multivalued Hamilton–Jacobi solutions.
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All authors F. Jiménez Alburquerque, M. Leok, C. Sardón, X. Zhao
Astrophysics of Galaxies
Tracing Radial Migration in the Outer Disk: A Comprehensive Analysis of the Old Open Cluster Berkeley 36
Deniz Cennet Ç{\i}nar, D. Bisht, Ing-Guey Jiang et al. (+2 more)
We present a chemo-kinematical, structural, and photometric analysis of the old open cluster Berkeley 36 using
Gaia DR3 astrometry and photometry together with high-resolution spectroscopy from the
Gaia-ESO Survey DR5.1. Applying a Gaussian Mixture Model to
Gaia astrometry, we identify 946 high-probability cluster members. We derive a core radius of 2.63 +/- 0.21 arcmin and a
tidal radius of 14.84 +/- 0.47 arcmin, indicating a moderately concentrated and dynamically relaxed system. By fixing the cluster
metallicity to the spectroscopic value of [Fe/H] = -0.19 +/- 0.02 dex and adopting an independently determined
geometric distance of 4377 +/- 510 pc, we minimize the classical age-reddening-
metallicity degeneracy and derive a robust isochrone age of 6.8 +/- 0.5 Gyr. Independent Ba-based chemical clocks yield a mean age of 7.75 +/- 1.94 Gyr, supporting the isochrone solution. The cluster exhibits a high main-sequence binary fraction of 48.0 +/- 1.7% and hosts 83 blue straggler
star candidates with an extended spatial distribution, contrary to classical mass segregation. Orbit integration shows that Berkeley 36 follows a nearly circular orbit in the outer
Galactic disc at R_GC = 11.42 +/- 0.44 kpc. Accounting for the
Galactic warp and disc
flare increases the cluster's maximum vertical excursion by 86% and the local disc scale height by 17%, respectively. Comparison with its chemically inferred birth radius at R_b = 6.71 +/- 0.66 kpc indicates an outward radial migration of approximately 5 kpc, predominantly driven by churning. These results establish Berkeley 36 as a
benchmark for investigating radial migration, secular
evolution, and the dynamical history of old
Galactic open clusters.
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All authors Deniz Cennet Ç{\i}nar, D. Bisht, Ing-Guey Jiang, K. Belwal, Selçuk Bilir
High Energy Physics (Theory)
Genuine Multi-Entropy in Abelian Chern–Simons Theory: Exact Key-Ring Collapse and Its Breakdown for Generic Link States
Yen-Cheng Chang, Kaberi Goswami, Norihiro Iizuka et al. (+1 more)
We study genuine multi-
entropy in Abelian $U(1)_k$ Chern-Simons theory. For key-ring link states, where only the linking numbers between one distinguished component $K$ and the remaining $\mathtt{q}-1$ components are nonzero, we derive an exact closed-form expression for the $\mathtt{q}$-partite Rényi multi-
entropy for general $\mathtt{q}$, level $k$, and Rényi index $n$. For $\mathtt{q}=4$, this shows that the genuine multi-
entropy $\mathrm{GM}^{(4)}_n$ collapses exactly onto the tripartite information $I_{3,n}$ for all $n$, while for $\mathtt{q}=5$ it is likewise completely determined, for all $n$, by a linear combination of tripartite and bipartite Rényi multi-
entropies. We then go beyond the key-ring class and study general four-component link states with arbitrary pairwise linking numbers. A numerical scan over Chern–Simons levels $2\leq k\leq24$ shows that the all-$n$ collapse found analytically for key-ring states does not survive for generic link states. Remarkably, the collapse remains exact at $n=2$ for every level examined. At $n=3$, violations occur, within the scanned range, only when $3\mid k$, with a further dependence on the $3$-adic valuation of $k$. At $n=4$ and $n=5$, violations occur for every level examined, with rates that vary strongly with $k$. These results show that the breakdown is not controlled simply by the zero-divisor structure of composite $\mathbb Z_k$, but instead exhibits a nontrivial joint dependence on the Rényi index and the arithmetic structure of the Chern–Simons level.
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All authors Yen-Cheng Chang, Kaberi Goswami, Norihiro Iizuka, Akihiro Miyata
Quantum Physics
Evolution Generators for Complex Parameters
Jen-Yin Yeh and Chia-Yi Ju
Theoretical studies on how
quantum systems are affected by external factors are often formulated through parameter changes in the system's
Hamiltonian. Beyond Berry connections and phases, which focus on specific
Hamiltonian eigenstates, recent studies inspired by non-Hermitian
quantum formalisms provide a framework for obtaining general state
evolution generators for real-valued parameters. This study extends the applicability of the
evolution generator formalism to complex-valued parameters via Wirtinger derivatives. By treating a complex parameter and its conjugate as independent variables, the
evolution equations are derived for both
quantum states and the metric of the
Hilbert space bundle. The analysis demonstrates that while state
evolution with respect to a complex parameter is naturally governed by its corresponding
evolution generator, metric
evolution requires a coupled contribution from both the generator and its conjugate counterpart to preserve state normalization. Explicit examples are worked out to illustrate the implementation and physical consistency of the formalism.
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High Energy Physics (Theory)
Higher-Spin dS/CFT beyond minimal type-A, and the doubled nature of de Sitter space
Julian Lang and Yasha Neiman
We study the
holographic duality between free vector models and Higher-
Spin Gravity in 4-dimensional de Sitter space. On both the bulk and boundary sides, we introduce new reality conditions, which allow us to include odd
spins in the bulk, and to extend the duality from type-A to type-B (i.e. from boundary scalars to spinors). The new reality conditions are closely related to a higher-
spin-symmetric
Hilbert-space norm for the single-particle (super)multiplet in de Sitter space. We construct two alternative viewpoints on the type-A and type-B theories. In one view, the two co-exist in "parallel universes", specifically in even vs. odd antipodal identifications of de Sitter space. In the other view, type-A and type-B are Legendre-transformed descriptions of the same twistor-space theory in Euclidean AdS (this involves the observation that the higher-
spin partition function is Legendre-dual to itself). In this way, higher-
spin holography reconciles the two-boundary nature of de Sitter space with the one-boundary nature of Euclidean AdS. The supersymmetric theory that unifies type-A and type-B with bulk
fermions fails to be consistent under the appropriate reality conditions.
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Instrumentation and Methods for Astrophysics
Self-calibration of adaptive optics systems. Application to the THEMIS solar telescope
Clementine Bechet, Eric Thiebaut, Michel Tallon et al. (+3 more)
The interaction
matrix models the effects of deformable mirror (DM) commands as perceived by the wavefront sensor (WFS) and is the cornerstone of the Adaptive Optics (AO) control. Difficulties to calibrate this
matrix arise due to the number of degrees of freedom, the non-linearity, and temporal
evolution of the AO system. An affine approximation of the unknown mapping between the DM commands and the WFS measurements is considered. Optimal
estimators of the parameters of this affine model are obtained by fitting, in the weighted least squares sense, WFS data acquired with random probe commands sent to the DM. Several calibration methods are being considered depending on whether the model is directly fit to the WFS data or to the differences between successive WFS data. We derive closed-form expressions of the
estimators of the components of the model. The proposed calibration methods can be applied under different conditions: before observing, on an internal source, or on-sky in open- or closed-loop. By introducing forgetting factors to reduce the weight of data as they age, we show that the model can be learned continuously using simple recurrence rules. The low computational complexity of these rules makes them suitable for real-time at the same frequency as the AO loop. We derive simple expressions for the mean squared errors (MSE) of the proposed
estimators. We apply the proposed calibration methods to real telemetry data from the AO system of the THEMIS
solar telescope. Our results show that the simple differences method is the method of choice: not only does it produce
estimators with the least MSE, but it is also very simple to implement compared to the push-pull method which is widely used in AO systems.
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All authors Clementine Bechet, Eric Thiebaut, Michel Tallon, Isabelle Tallon-Bosc, Bernard Gelly, Richard Douet
Materials Science
Solid and Quasi-Solid Electrolytes for Zinc Batteries: Balancing Water Activity, Ion Transport, and Interfaces
Souvik Naskar, Jiaqian Qin and Eric Jianfeng Cheng
Zinc batteries offer a compelling route to safe and low-cost energy storage, yet their reliance on aqueous electrolytes promotes hydrogen
evolution, corrosion, cathode dissolution, and non-uniform zinc deposition. Replacing the
liquid with a solid or quasi-solid electrolyte can suppress these processes, but it also removes the medium that enables rapid Zn2+ transport and conformal electrode contact. This tension, the price of removing water, has been obscured by inconsistent use of the term solid state and by comparisons based largely on bulk ionic conductivity. Here we critically examine zinc electrolytes across a continuum from water-rich hydrogels to dry
polymers, solvated
crystals, and inorganic conductors. We distinguish water content from thermodynamic water activity and classify these materials according to phase state, mobile-solvent fraction, and dominant transport mechanism. We show that neither high conductivity nor nominally water-free composition reliably predicts
cell performance: electrolyte thickness, Zn2+ transference, interfacial resistance, and evolving contact often determine the practical outcome. Controlled-solvation and hybrid electrolytes therefore provide the most credible near-term path, whereas genuinely solvent-free Zn2+ conductors remain a longer-term scientific target. Progress will require transparent reporting of solvent state and validation using thin electrolytes, realistic electrode loadings, limited zinc excess, and calendar-life testing.
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Plasma Physics
Unified Gas-Kinetic Wave-Particle Method for Multiscale Simulation of Vlasov-Poisson-Fokker-Planck System
Zhigang Pu, Chang Liu, Yixiao Wang et al. (+1 more)
A unified gas-kinetic wave–particle method with Fokker–Planck collisions (UGKWP-FP) is developed for the Vlasov–Poisson–Fokker–Planck system. The collision operator is modeled by the Lenard–Bernstein operator, whose
stochastic representation corresponds to the Ornstein–Uhlenbeck process in velocity space. To extend the UGKWP framework beyond the conventional Bhatnagar–Gross–Krook (BGK) collision model, the Fokker–Planck operator is decomposed into a nonstiff drift–
diffusion contribution and a stiff thermalization contribution. The former is retained in the particle dynamics through a modified Ornstein–Uhlenbeck process, whereas the latter is represented by a BGK-type relaxation toward the local Maxwellian. This decomposition enables an adaptive wave–particle representation: the method follows
stochastic particle dynamics in rarefied regimes and increasingly represents the rapidly equilibrating distribution by the analytical wave component as the continuum regime is approached. The modified friction coefficient is constructed to recover the original Fokker–Planck dynamics in the rarefied limit while preserving the hydrodynamic limit under strong collisions. Numerical experiments demonstrate that the proposed method captures velocity-space drift and
diffusion, recovers the expected kinetic and continuum behavior across a range of Knudsen numbers, and reproduces the characteristic
evolution of collisional
plasma phenomena.
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All authors Zhigang Pu, Chang Liu, Yixiao Wang, Kun Xu
Instrumentation and Methods for Astrophysics
AO3k + SCExAO: on-sky wavefront quality and demonstration of novel WFS techniques with the double XAO system
Julien Lozi, Kyohoon Ahn, Vincent Deo et al. (+5 more)
The Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) system, fed by its upstream 3000-actuator "woofer" (AO3k), serves both as a platform for high contrast imaging (HCI) technology maturation and as a science instrument for imaging, spectroscopy, and polarimetry of
exoplanets and disks. SCExAO operates in the visible and near-IR and offers a wide choice of instrument configurations. Over the last year, AO3k/SCExAO underwent significant upgrades to bring improved capabilities and support new developments, all while easing science operations. The new configuration features a beam switcher so that light can be shared between several instrument modules. The system is evolving toward a tighter integration between multiple WFSs and AO stages of correction, with the first stage (AO3k) providing visible and nearIR WFSing, as well as
laser tomography. AO3k+SCExAO has been fully operational since October 2025, demonstrating very high stability on-sky, even in bad seeing conditions up to 2". Having two XAO in series allows us to deploy advanced wavefront control techniques optimized for high-contrast imaging (e.g. speckle nulling, EFC, Coronagraphic LOWFS, Fast and Furious) on the second-stage XAO loop, as AO3k by itself delivers high-contrast PSFs already. Areas of active ongoing research include use of photonic devices for spectrally dispersed interferometric sensing, PSF reconstruction from WFS telemetry, and non-linear sensors (focal plane and
curvature). Recent upgrades to the computer infrastructure are aimed at supporting these R&D efforts and providing a rich collaborative environment for experimentation. In this paper, we will present on-sky high-contrast performance characterization of AO3k, AO3k+SCExAO, and on-sky demonstrations of novel wavefront control techniques to improve the contrast behind the coronagraph.
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All authors Julien Lozi, Kyohoon Ahn, Vincent Deo, Olivier Guyon, Sandrine Juillard, Yoshito Ono, Garima Singh, Sébastien Vievard
Mesoscale and Nanoscale Physics
Extreme Polarization of the Optical Gap and High-Energy Exciton Landscape in CrSBr
Sayantan Patra, Sourabh Jain, Bhumika Chauhan et al. (+8 more)
We reveal a strongly anisotropic excitonic landscape in monolayer and bulk-like CrSBr using optical absorption spectroscopy and $GW$-Bethe-Salpeter equation $\textit{ab initio}$ calculations. The direct absorptive determination of the lowest bright optical onsets i.e. $X_0^a$ and $X_0^b$
excitons for the two in-plane polarization eigenaxes yield an in-plane optical gap anisotropy of $470 \pm 15$ meV. This is the highest observed value for any material in the near-infrared-to-visible spectral region to the best of our knowledge. Energetically above, we identify multiple strongly polarized
excitons spanning $1.25$ eV to $3.1$ eV selectively aligned along the two orthogonal axes. A resonance $X^-$, located $24$ meV below the $X_0^b$ progressively transfers oscillator strength to $X_b^0$, a behavior consistent with a coupled trion (
Fermi-polarion)/
exciton pair. Our experiments also provide polarization-resolved broadband dielectric functions of CrSBr. These results establish CrSBr as a strongly polarization-selective excitonic system and highlight its potential for polarization-selective optoelectronics enabled with its large optical-gap anisotropy.
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All authors Sayantan Patra, Sourabh Jain, Bhumika Chauhan, Marie-Christin Heißenbüttel, Abhisek Saidarsan, Ranjuna M. K., Kseniia Mosina, Zdeněk Sofer, Michael Rohlfing, Thorsten Deilmann, Ashish Arora
Quantum Physics
Thresholdless dynamical instability in transverse $\mathcal{PT}$-symmetric scattering systems: The hidden role of bound states in the continuum
Chao Zheng
The stationary scattering properties of transverse parity-time ($\mathcal{PT}$) symmetric systems have been extensively studied, yet their dynamical stability, a prerequisite for any stationary description, remains largely unexplored. Here we uncover a thresholdless dynamical instability in such systems, driven by
symmetry-protected bound states in the continuum (BICs). Without gain and loss, the up-down mirror
symmetry of the transverse geometry generically protects a BIC, which manifests as the coalescence of an $S$-
matrix pole and zero on the real axis of the complex wave-number plane. A Hermitian
symmetry-breaking perturbation shifts the poles into the lower half-plane, converting the BIC into a resonance with a
Fermi-golden-rule decay width. An anti-Hermitian $\mathcal{PT}$-symmetric perturbation instead reverses the sign of the second-order energy shift, driving the poles into the upper half-plane and producing a time-growing bound state with $\operatorname{Im}E=\gamma^{2}\Gamma_{V}/2+O(\gamma^{3})$, where $\gamma$ is the gain-loss strength and $\Gamma_{V}$ is the golden-rule coupling of the BIC to the continuum. The instability therefore sets in at arbitrarily small $\gamma$ whenever $\Gamma_{V}>0$. We confirm this mechanism in a three-site side-coupled model that is unstable despite possessing a
unitary scattering
matrix, and in a four-site rhombic model where transverse and longitudinal gain-loss placements yield vanishing and finite thresholds, respectively. These results establish a microscopic stability criterion and a design principle for stable $\mathcal{PT}$-symmetric scattering devices.
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General Relativity and Quantum Cosmology
Null Completeness and Directional Rigidity in Bianchi I Spacetimes
Ye Zhou and Alan Zhang
In Einstein
gravity, every null geodesic of a non-static Bianchi I spacetime satisfying the null energy condition is incomplete in at least one direction within the Bianchi I region. We prove a stronger directional
rigidity theorem: a single null geodesic complete in both affine directions forces staticity if the null
curvature is nonnegative along it and, at each time, in one transverse null direction. The spatial metric need not be diagonal, and the expansion rates may have either sign. The proof uses caustic-free null congruences whose conserved spatial covectors define fixed screen hyperplanes. The two
curvature conditions admit averaged replacements along the geodesic and, when
cosmic time is complete, along comoving worldlines. In a non-static metric, at most four oriented directions are optically saturated; every other complete null geodesic has strictly negative averaged null
curvature. Periodic and finite-pulse examples attain this bound with NEC-violating sources and nonpositive total energy density. For finite pulses, we derive bounds on metric excursions from three directional
curvature budgets at fixed
cosmic duration, and on the mode mixing of a free, massless, minimally coupled test scalar field from the averaged null-energy deficit at fixed affine duration.
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Fluid Dynamics
Competing instabilities in wide-gap viscoelastic Taylor-Couette flow: Taylor vs. helical vortices
Alexander Proskurin
This paper presents a numerical study of the stability of a
polymer solution flow between concentric cylinders with a rotating inner cylinder. The case of a small-radius inner cylinder is considered. The fluid motion is described using a specific case of the Kelvin-Voigt model, often referred to as the Oskolkov model. This model is applicable to very dilute
polymer solutions, where the retardation time is much smaller than the characteristic time of the problem and elastic forces are much smaller than viscous forces. The stability of the steady-state motion is investigated using a fully nonlinear approach by means of direct numerical simulation of a perturbation introduced as finite-duration white noise. Depending on the Reynolds number, the perturbation either decays or grows. The critical Reynolds numbers obtained for both Newtonian and non-Newtonian fluids are found to be in agreement with the predictions of the linear theory. It is also shown that an increase in the elastic forces makes helical perturbations more dangerous than their axisymmetric counterparts.
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Optics
Programmable generation of optical skyrmions on a silicon photonic chip
Mingyuan Zhang, Xiaofu Pan, Wu Zhou et al. (+6 more)
Optical skyrmions, characterized by topologically stable and spatially varying polarization textures, show immense potential for robust optical communications and metrology. However, conventional methods for generating optical Stokes skyrmions rely on bulky free-space optics, strictly constraining both system miniaturization and dynamic reconfigurability. Here, we demonstrate the efficient and programmable generation of optical skyrmions and bimerons using a compact silicon photonic chip. By integrating a programmable Mach–Zehnder interferometer mesh with a multi-dimensional grating emitter, we dynamically control the amplitudes, phases, and polarizations of emitted fundamental and orbital angular momentum modes. This architecture allows on-demand electrical switching among a complete library of optical quasi-particle states, including Néel, Bloch, intermediate, and anti-type skyrmions and bimerons. Experimental full-Stokes polarimetry confirms high-fidelity polarization textures with near-unity skyrmion numbers. Our foundry-compatible platform translates complex topological light generation into simple voltage controls, paving the way for next-generation communication and sensing systems based on optical skyrmions.
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All authors Mingyuan Zhang, Xiaofu Pan, Wu Zhou, Wenzhang Tian, Zengqi Chen, Yiou Cui, Yijie Shen, Yeyu Tong, Jianqi Hu
High Energy Astrophysical Phenomena
Photon–Dark Matter Elastic Scattering: An Effective-Operator Scan and First Operator-Resolved Sensitivity Estimates from the Galactic Halo
Trinity Rosebud Stenhouse, Asli Acar, Mikhail Bashkanov et al. (+3 more)
Elastic
photon–dark matter scattering attenuates gamma-ray spectra along a line of sight, probing the same operators as dark matter annihilation to
photons but at a rate linear, rather than quadratic, in dark matter density. We consider Standard Model gauge-invariant effective operators of mass-dimension 5 to 7, suppressed by a cutoff scale $\Lambda$, coupling scalar, Majorana or Dirac dark matter to the
photon. The leading operators with non-vanishing real-
photon amplitudes enter at dimension-5 for Dirac dark matter and dimension-7 for Majorana dark matter. In the electroweak-doublet dipole portal, the inelastic splitting invoked to evade direct detection also closes the CMB annihilation bound, leaving attenuation the only one of the three
photon-sector probes that survives. Applying this to a pixel-level reanalysis of 17 years of
Fermi–LAT Pass~8 data toward the
Galactic centre, we derive the first operator-resolved sensitivity estimates for
photon–dark matter scattering from the
Galactic halo: $\Lambda \simeq 0.32~\mathrm{GeV}$ for the dimension-5 Dirac dipoles, $0.21~\mathrm{GeV}$ for the dimension-6 scalar Rayleigh operator and $0.79$–$1.06~\mathrm{GeV}$ for the dimension-7 Rayleigh family. The reach is weak: it lies below the EFT-validity threshold across the cold dark matter mass range, and is superseded on the dipole plane by CMB and direct-detection constraints. The framework is calibrated against pseudo-experiments, and recomputes the sensitivity for any instrument that provides a per-bin spectrum with uncertainties and a line-of-sight column density.
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All authors Trinity Rosebud Stenhouse, Asli Acar, Mikhail Bashkanov, Frank F. Deppisch, Chamkaur Ghag, Dan P. Watts
Mathematical Physics · Cross-listed from math.AP
Time-modulated refocusing in inhomogeneous medium
Hongyu Liu and Wei Wu
In an inhomogeneous dissipative medium, different rays experience different round-trip attenuation, so an instantaneous time mirror may retrace rays without producing a balanced point focus. We solve this problem for a microlocally selected back-propagating transverse-
magnetic component generated by a short pulsating modulation of a thin shell surrounding an inhomogeneous Debye medium with Ohmic conductivity. An exact decomposition of the Maxwell–Debye field isolates the pulse-generated return, and a semiclassical mode reduction yields a scalar returned operator whose principal symbol separates the temporal pulse response, shell modulation, and accumulated material loss. Our analysis shows that
geometric distortion and amplitude attenuation are both involved in wave propagation, but the
geometric distortion cancels between the outgoing and returning branches, whereas physical attenuation remains. A normalized directional energy, computed from pre-modulation measurements using the known lossless backward propagator, contains the same leading attenuation factor as the returned symbol. Its reciprocal defines a smooth, nonnegative, physically admissible modulation that equalizes the selected source-side gain up to a relative $O(h)$ error without requiring a complete attenuation model. With such a modulation, the field generated by a point source has a focal-scale leading profile independent of directional attenuation, with a unique maximum at the source and coherent return time. In every fixed focal window, the maximum is displaced by at most $O(h^2)$ in space and time, and the spatial half-amplitude area is $O(h^2)$.
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High Energy Physics (Theory)
Teleparallel formulation of $E_{8(8)}$ Exceptional Field Theory
Davide Rovere
The potential of $E_{8(8)} \times \mathbb{R}^+$ exceptional field theory, suited for studying three-dimensional maximally supersymmetric compactifications of higher-dimensional supergravities, is derived in teleparallel formulation. This means that, starting from an ansatz of the most general combination of the quadratic scalar contractions of the intrinsic torsion, which is manifestly invariant under generalised diffeomorphisms, one selects the potential by imposing the invariance under infinitesimal rotation of the maximal compact subgroup of the duality group. The teleparallel formulation makes manifest at
geometric level the preeminent role of the intrinsic torsion in studying compactifications of higher-dimensional supergravities, where the intrinsic torsion is identified with the
embedding tensor of the resulting gauged supergravity.
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Physics and Society
Integrating adaptive human behavior into epidemic models with large language models
Yicheng Mao, Haoyang Li, Rob Deardon et al. (+1 more)
Infectious disease transmission is shaped by patterns of human interaction, which adapt as epidemic conditions change. Capturing these context-dependent behaviors remains a fundamental challenge for epidemic models. Here, we recast this challenge by using large
language models (LLMs) to represent adaptive human behavior within mechanistic epidemic models. We operationalize this idea through Generative Adaptive Behavioral Layer for Epidemics (GABLE), which adapts LLMs to infer behavioral responses to epidemic and policy conditions and translates them into age-structured contact
matrices coupled to a mechanistic epidemic model. Applied to COVID-19 in France, GABLE reproduced responses in population mixing and age-specific contact structures that remained epidemiologically informative. In short-term
forecasting, LLM-generated contact
matrices outperformed mobility-driven
matrices derived from real-world mobility data, with the largest gains at longer horizons. GABLE also extends beyond
forecasting to prospective policy evaluation by projecting behavioral and epidemic responses to candidate interventions before implementation. When supplied with subsequently implemented policies, GABLE reproduced epidemic trajectories and generated distinct responses to alternative policy timing and composition. By leveraging LLMs as a flexible behavioral layer, GABLE provides a framework for coupling context-sensitive behavioral generation with epidemic dynamics.
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All authors Yicheng Mao, Haoyang Li, Rob Deardon, Hongru Du
Atmospheric and Oceanic Physics
Python-Fortran Hybrid Programming to Fuse AI and Physical Models: Examples of AI-LDA in climate and weather models (Hf2pMDA_v1.0)
Xianrui Zhu, Zikuan Lin, Shaoqing Zhang et al. (+12 more)
AI provides an unprecedented opportunity for advancing physics numerical modeling including data assimilation, which is a highly efficient and critically-important tool for advancing our understanding on Earth system and its applications. At the same time, deep incorporation of AI and physical modeling can make great driving to advance AI by injecting it rich physics from long time physics-based modeling development. However, since such physics models are conventionally coded in Fortran and AI
algorithms usually are conveniently designed in Python, difficulties exist to directly incorporate AI
algorithms into physics models, vice versa. Here, based on the F2PY protocol, we have developed a procedure that implements an infrastructure which conveniently conducts Hf2pMDA to form a program entity so that AI
algorithms and physical models can invoke mutually. As examples, within Hf2pMDA, a
climate coupled data assimilation (CDA) system is naturally upgraded to a strongly CDA (SCDA) system, and a 1 km high-resolution weather DA system is conveniently implemented within a multi-layer downscaling model that has multiscale DA in different nesting layers. In the
climate SCDA system, a coupled general circulation model (CGCM) and a multiscale filtering
algorithm is integrated by a Python main controller (PMC) that calls Fortran CGCM components and Weakly-CDA modules as well as a data-trained SCDA
algorithm by latent space autoencoder in Python. In the high-resolution weather DA system, the downscaled model consisting of traditional Fortran DA modules in all mother domains and Python AE DA
algorithm in the central child domain is integrated by a PMC that organizes these components. With convenient realization of deep incorporation of any AI
algorithm and physics model, the Hf2pMDA has a great potential to make progress on both AI and scientific modeling.
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All authors Xianrui Zhu, Zikuan Lin, Shaoqing Zhang, Zebin Lu, Songhua Wu, Xiangyun Hou, Zhisheng Xiao, Zhicheng Ren, Jiangyu Li, Jing Xu, Yang Gao, Rixu Hao, Xiaolin Yu, Mingkui Li, Guangliang Liu
Mathematical Physics
Kubo Formulas and Bulk-Edge Correspondence for Curved Boundaries
Aren Martinian and Tom Stoiber
Strong topological
insulators are classified by integer invariants which admit different real-space expressions. Inspired by recent work studying these invariants for spaces with curved boundaries, we revisit the problem of equivalence of the various expressions, including Fredholm index pairings and Kubo formulas involving half-space projections. Using Roe
algebras and a variant of KK-theory suitable for non-separable $C^*$-
algebras, we prove a general form of bulk-edge correspondence for the index pairing with a general position-space Dirac operator in the presence of arbitrary boundaries. For spaces coarsely equivalent to $\mathbb{R}^d$, we show that up to multiplicity, these pairings are equal to those obtained with the standard dual Dirac operator, with the multiplicity explicitly given as the topological degree of the symbol function. In addition, we prove a generalized Kubo formula which computes the general index pairing by a real-space formula.
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Quantum Physics
Demonstration of traveling-wave interactions between spontaneous photon emissions and atoms in a chiral F-P cavity
Jiajin Lu, Minjie Wang, Haole Jiao et al. (+4 more)
The enhancement of atom-
photon interactions with F-P cavities provides a suitable platform for studying
quantum optics and atomic physics. However, the emission fields in linear F-P cavities are in the standing-wave mode, which leads to non-uniform atom-
photon coupling and a short storage lifetime of cavity-enhanced
spin-wave
quantum storages. This study experimentally demonstrates traveling-wave atom-light interactions in an F-P cavity that can preserve light helicity. First, a bias
magnetic field is applied along the z-axis to define the quantization axis, which lifts the Zeeman degeneracy and breaks the time reversal
symmetry. Next, non-classically correlated pairs of Stokes
photons and
spin waves are produced based on the Duan-Lukin-Cirac-Zoller scheme. The Stokes
photons initially emitted from a single circularly polarized atomic transition have left-and right-hand circular polarizations when propagating along the +z (forward) and -z (backward) directions, which are preserved in the
chiral cavity within the atom-
photon interaction region. Thus, when the forward and backward Stokes fields resonate with the cavity, they may interact with the atoms in a traveling-wave manner. This is confirmed by measuring the time-dependent
retrieval efficiencies of
spin waves correlated with the forward and backward Stokes fields. This work paves the way for demonstrating traveling-wave atom-
photon interactions in F-P cavities.
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All authors Jiajin Lu, Minjie Wang, Haole Jiao, Xiang Chen, Hongze Zhang, Shujing Li, Hai Wang
High Energy Physics (Experiment)
Low-energy Muon-Nucleon scattering experiment: LUNE (White Paper)
Chenlei An, Dong Bai, Ziyu Bai et al. (+70 more)
The HIAF will provide high-intensity, high-quality
muon beams with momenta from 0.5 to 7.5 GeV/c. This energy range is uniquely suited for precision
muon scattering, bridging the gap between low-energy electron facilities and future high-energy
lepton-ion
colliders. In particular, HIAF will enable precision measurements with both positive and negative
muon beams over a broad kinematic range, complementing existing electron-scattering facilities such as JLab, EicC and EIC. Based on HIAF
muon source, the LUNE Collaboration has been established to address several fundamental questions in
nuclear and particle physics, including the
proton charge radius puzzle, nucleon electromagnetic structure, and the dynamics of
quantum electrodynamics and hadronic interactions. The program proceeds in two phases, from elastic scattering to nucleon structure and beyond-Standard-Model searches. The experiment is expected to determine the
proton charge radius with a precision of approximately 1.0% using elastic
muon-
proton scattering. It will also perform systematic measurements of the
proton electromagnetic form factors with both $\mu^+$ and $\mu^-$ beams, enabling precise studies of two-
photon exchange effects and stringent tests of
quantum electrodynamics. Beyond elastic scattering, LUNE will investigate TMD, gravitational form factors, and
nuclear charge radii, providing new insights into the 3D structure of nucleons and
nuclei. The experiment will further address important topics including Coulomb-distortion corrections,
nuclear medium effects, and possible signatures of physics beyond the Standard Model. This white paper presents the scientific motivation, detector concept, expected performance, and long-term strategy of LUNE.
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All authors Chenlei An, Dong Bai, Ziyu Bai, Kai Chen, Liangwen Chen, Xiang Chen, Jianqiao Deng, Yanxin Dou, Yicheng Feng, Zekai Feng, Lu Gao, Chang Gong, Aiqiang Guo, Liang Han, Qundong Han, Defu Hou, Ruiwen Hou, Huigang Hu, Chen Ji, Xiangdong Ji, Vijay Kumar, Dikai Li, Jiuzhao Li, Liang Li, Qite Li, Xin-Qiang Li, Yuan Li, Qiming Liang, Yutie Liang, Dong Liu, Duanqing Liu, Langtian Liu, Weijie Liu, Zejia Lu, Maowu Nie, Ziwen Pan, Hua Pei, Jinkang Peng, Shusu Shi, Qintao Song, Xiaocheng Song, Xiangming Sun, Yichen Sun, Zhiyu Sun, Enke Wang, Fei Wang, Hulin Wang, Jike Wang, Xiang-Peng Wang, Xiao Wang, Xin-Nian Wang, Yangxi Wang, Yaping Wang, Zeren Simon Wang, Yanbing Wei, Yuehong Xie, Weizhi Xiong, Nu Xu, Yu Xu, Siqi Yang, Yadong Yang, Hang Yin, Xing-Bo Yuan, Dongliang Zhang, Ranyu Zhang, Ruitian Zhang, Xueheng Zhang, Yu Zhang, Yuxiang Zhao, Zihan Zhao, Shuai Zhou, XiaoKang Zhou, Xiaoyu Zhu
High Energy Physics (Experiment)
From a Long-standing Prediction to a New Family of Hadrons
Xining Wang and Kai Yi
Fully charmed tetraquarks have evolved from a long-standing theoretical prediction into one of the most active frontiers in
hadron spectroscopy. This article reviews their development from early theoretical studies and experimental searches to the recent breakthroughs at the Large
Hadron Collider, with particular emphasis on the contributions of the Nanjing Normal University (NNU) and Tsinghua University (THU) teams at the CMS experiment. We summarize the discovery of the fully charmed tetraquark family, the establishment of interference among resonances, and the first determination of their
quantum numbers. These advances have transformed the search for a single exotic resonance into the study of a new family of
hadrons and opened a promising avenue for exploring the nonperturbative dynamics of
Quantum Chromodynamics.
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Mathematical Physics · Cross-listed from math.NA
ENPINN: Energy-Norm-Guided Gradient-Enhanced PINNs for Generalized Transport Problems with Sharp Gradients
Subhendu Maity, Pratibhamoy Das, Arihant Patawari et al. (+1 more)
Physics-informed neural networks (PINNs) have emerged as a meshless alternative to conventional numerical methods for solving partial differential equations (PDEs). However, their limited ability to capture sharp gradients can lead to substantial errors when resolving boundary and interior layers. Here, we introduce an energy-norm-enhanced PINN (ENPINN) that incorporates gradient information and variational structure into the loss function to improve the resolution of layer-dominated solutions. We first examine two related formulations: weak-loss PINNs (WLPINNs), which incorporate test functions into the conventional PINN residual, and gradient-enhanced PINNs (gPINNs), which augment the loss with spatial derivatives of the PDE residual. By analyzing these formulations, we identify their limitations in resolving steep solution gradients and motivate the systematic construction of ENPINN. We establish theoretically how the energy-norm error depends on the ENPINN loss and show that a suitably modified residual-derivative term is essential for accurately capturing boundary layers. We further establish the existence of neural-network approximations with arbitrarily small energy error and derive corresponding derivative bounds, providing a theoretical foundation for the proposed framework. The performance of ENPINN is assessed through systematic comparisons with existing PINN variants for convection-
diffusion-reaction problems exhibiting steep gradients. Numerical experiments include a combustion model, a coupled multi-scale system, a two-dimensional Burgers equation with an interior layer, and a three-dimensional time-dependent problem.
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All authors Subhendu Maity, Pratibhamoy Das, Arihant Patawari, Ameya D. Jagtap
Quantum Physics
Boyang Chen, Tomoyuki Morimae and Takashi Yamakawa
Pessiland is a world where NP is hard on average but one-way functions (OWFs) do not exist [Impagliazzo 1995]. Because almost all classical cryptographic primitives imply OWFs [Impagliazzo and Luby 1989], there is almost no classical cryptography in Pessiland. On the other hand,
quantum cryptography can exist even when OWFs do not [Kretschmer 2021; Morimae and Yamakawa 2022; Ananth, Qian and Yuen 2022]. Is there a
quantum analogue of Pessiland where NP is hard on average but even
quantum cryptography does not exist? In this paper, we show that such a miserable world,
Quantum Pessiland, exists: there is a
quantum oracle relative to which $UP\cap coUP$ is hard on average against
quantum polynomial-time
algorithms with
quantum advice, yet auxiliary-input EFI pairs do not exist. We also show that there is a classical oracle relative to which $UP\cap coUP$ is hard on average against
quantum polynomial-time
algorithms with
quantum advice, yet classically-secure auxiliary-input one-way puzzles (OWPuzzs) do not exist. Almost all
quantum cryptographic primitives imply EFI pairs or OWPuzzs, and therefore these results mean that there is almost no
quantum cryptography relative to these oracles. We further show that relative to the classical oracle, SampBQP = SampBPP, and therefore there is no sampling-based
quantum advantage in
Quantum Pessiland. Finally, because our average-case hardness of $UP\cap coUP$ implies $P^{\#P}\not\subseteq i.o.BQP/qpoly$, our result also implies that a non-relativizing proof technique is necessary to construct OWPuzzs solely from $P^{\#P}\not\subseteq i.o.BQP/qpoly$, which gives a partial negative answer to the open problem of [Khurana and Tomer 2025].
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