Computational Physics
Probabilistic Inverse Modeling of Contaminant Transport via a Conditioned-on-Design Bayesian Physics Informed Neural Network
Milad Panahi, Giovanni Michele Porta, Monica Riva et al. (+1 more)
We address the inverse problem of reactive transport in heterogeneous porous media, where unknown model parameters must be inferred from sparse experimental observations. The problem is complicated by strong nonlinearities, spatial heterogeneity, and limited data availability. We propose a Conditioned-on-Design
Bayesian Physics-Informed Neural Network (CoDe-BPINN), which combines a domain-decomposed PINN solver with a
Bayesian inference network that learns the conditional distribution of model parameters given experimental design variables. The framework is trained by maximizing a physics-informed Evidence Lower Bound (ELBO), enabling simultaneous reconstruction of spatiotemporal concentration fields, probabilistic parameter estimation, and uncertainty quantification. We demonstrate the approach using laboratory experiments on contaminant transport through a multilayer porous column with an iodinated contrast medium. The model accurately reproduces breakthrough dynamics while revealing systematic parameter dependence on flow conditions. In particular, it identifies a nonlinear decrease in effective sorption capacity with increasing flow rate and porosity, consistent with kinetic limitations and reduced adsorbent mass. The
Bayesian formulation also uncovers a strong negative correlation between sorption affinity and sorption capacity, quantifying the intrinsic non-identifiability of the inverse problem. CoDe-BPINN provides a robust framework for parameter inference and uncertainty quantification in data-scarce reactive transport problems.
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All authors Milad Panahi, Giovanni Michele Porta, Monica Riva, Alberto Guadagnini
Earth and Planetary Astrophysics
The PANSY Meteor Head-echo Orbit Catalogue: Continuous Antarctic Radar Observations of Southern Meteoroid Streams
Juha Vierinen, Jorge L. Chau, Koji Nishimura et al. (+7 more)
Meteor head echoes from high-power, large-aperture radars provide pulse-resolved positions and velocities for individual micrometeoroids in a submillimeter-radius range that contribute significantly to the mass influx to Earth. We present the first meteor head-echo orbit catalogue from the Antarctic Syowa Mesosphere–Stratosphere–Troposphere/Incoherent Scatter radar (PANSY). The catalogue contains two million meteors and 50 million pulse-resolved measurements. The observed radiant distribution contains the helion, antihelion, south toroidal and apex sources, and provides unprecedented head-echo coverage of southern ecliptic latitudes. The initial detection-height distribution is found to be double-banded, with both bands increasing in height with meteor speed and exhibiting distinct radiant distributions, consistent with a mixture of meteoroid-size differences and differential ablation. Estimation of dynamic mass indicates that the survey is sensitive to initial radii of approximately 100 micrometers. As part of an initial exploration of the catalogue, we investigate the nighttime alpha Capricornids (CAP) and the extended Daytime Capricornids-Sagittariids (DCS) radiant. Their similar activity durations at opposite nodes are consistent with membership in the CAP–169P/NEAT complex. The radiant distribution suggests a new meteor shower candidate, with peak flux near
solar longitude 110 degrees, mean Sun-centered ecliptic radiant longitude 291.0 degrees, latitude -48.2 degrees, and geocentric speed 48.7 km s^{-1}. During catalogue production, event-level raw voltage cuts are retained temporarily to support improvements in data analysis. This first catalogue release, covering 2025 January 26 to 2026 July 26, will be useful for further studies of the southern-hemisphere Earth-crossing meteoroid population.
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All authors Juha Vierinen, Jorge L. Chau, Koji Nishimura, Taishi Hashimoto, Nico Pfeffer, Daniel Kastinen, Devin R. Huyghebaert, Johan Kero, Masaki Tsutsumi, Kaoru Sato
Popular Physics
Entropy and Frenesy: the arrow and the bustle of time
Christian Maes
Nonequilibrium statistical mechanics is the science of time as it manifests itself in the transient or steady
entropy producing dynamical condition of many-body systems. Beyond the vivid multiformity of the phenomena themselves, three foundational issues lie at its heart. The first question concerns the very origin of
entropy production, which gives macroscopic processes their direction and thereby defines the arrow of time: how does an atomistic mechanical world give rise to dissipated heat, thermalization, and time-reversal
symmetry breaking? The second asks why, far beyond the familiar behavior of
equilibrium systems, driving or agitation may produce and select stable and functionally rich structures: what is it about far-from-
equilibrium, low-
entropy driving that unleashes the wealth and intricacy of the natural world? The third issue is partly methodological: to determine how, and for which subclass of such wildly diverse nonequilibrium systems, a systematic, unified description and modeling from first principles remains possible. This essay addresses these issues in an informal, semi-popular-science style, offering a personally engaging yet wide-ranging introduction to the complementary roles of
entropy production and the less familiar, more recently coined notion of frenesy in the dynamical fluctuations of steadily driven systems. Together, we argue, they provide a more complete starting point for understanding physical time on mesoscopic to macroscopic scales.
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Quantum Physics
Automating Variational Quantum Sensing through Reinforcement-Learned Circuit Structures
Jie Liu and Xin Wang
Variational
quantum sensing offers a promising route to high-precision parameter estimation, but its performance depends strongly on the
circuit architectures used for probe preparation and measurement. Existing approaches typically optimize continuous parameters within predefined ansätze, restricting the accessible design space and limiting adaptation to sensing tasks and hardware constraints. Here, we introduce AutoQSense, a reinforcement-learning framework that searches
circuit architectures using Fisher-information-based objectives. For few-
qubit systems, a single
agent sequentially constructs preparation and measurement
circuits. For larger systems, a distributed formulation assigns local
circuit design to subsystem
agents and inter-block
entanglement to a budgeted
agent. Numerical results show that the learned architectures recover known
benchmark strategies, adapt to dephasing noise, and outperform fixed hardware-efficient ansätze while using fewer entangling gates. These results establish AutoQSense as a resource-aware approach to adaptive and hardware-compatible
quantum sensing.
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Fluid Dynamics
Modelling flow-driven pore closure of weakening poroelastic media
Matthew V. Ghosh, Matthew G. Hennessy, Andreas Münch et al. (+1 more)
Poroelastic materials, such as
polymer tissue scaffolds, porous rocks, and hydrogels, can weaken due to interactions between the solid skeleton and chemical species in the interstitial fluid. We develop a mathematical model for a poroelastic material to provide fundamental mechanistic insight into how weakening the material can affect the time-varying mechanics of the system. Our model couples large-deformation poroelasticity with an advection-
diffusion equation for the solute. Furthermore, we introduce a decay equation for the material stiffness, whose rate of decay depends on the solute concentration. In this way, we describe a three-way coupling between poroelastic deformation, weakening of the skeleton and transport of solute through the material. We exploit numerical and analytical techniques to reveal the flow-driven uniaxial compression of a weakening poroelastic material and determine parameter regimes for which weakening the material facilitates pore closure at the downstream boundary. We identify parameter regimes in which (1) a steady state is attained without pore closure, (2) pore closure occurs at a finite time or (3) the pores close instantaneously; we uncover case (2) through the introduction of weakening into the system. We provide insights into the relationship between the differing behaviours and the separation between the timescales of the system. For systems with slow weakening, we derive a leading-order approximation for the time of pore closure, treating the ratio of the timescales of poroelastic relaxation and weakening as a small parameter, and investigate the accuracy of this approximation and the new behaviours that arise when these timescales become comparable.
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All authors Matthew V. Ghosh, Matthew G. Hennessy, Andreas Münch, Sarah L. Waters
Optics
Parallel single-pixel imaging based on modulation region expansion and overlapping reconstruction
Yinran Shen, Xuri Yao, Shijian Li et al. (+4 more)
Parallel single-pixel imaging (PSPI) enhances the data acquisition efficiency of single-pixel imaging, but its reconstruction quality depends on a cumbersome and noise-sensitive calibration process. To address this challenge, a PSPI strategy was introduced that leverages modulation region expansion and overlapping reconstruction. This method results in the calibration of modulation of the subregion for each detector, enabling robust operations with undersampled data. It compensates for misalignment via modulation region expansion and overlapping reconstruction, achieving seamless and high-quality imaging that surpasses conventional PSPI in simulations and experiments. Furthermore, this strategy exhibits remarkable robustness, maintaining high imaging quality under extremely nonideal conditions, such as large deflection angles between the array detector and the modulator. This work provides a simple, efficient, and robust framework that simplifies the PSPI workflow and offers broad applicability in high-resolution, high-speed computational imaging.
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All authors Yinran Shen, Xuri Yao, Shijian Li, Chao Shen, Yuhao Wang, Chongwu Shao, Qing Zhao
Chemical Physics
Operando multidimensional spectroscopy reveals A-site-dependent carrier cooling in perovskite solar cells
Edoardo Amarotti, Luca Bolzonello, Qi Shi et al. (+6 more)
Understanding how photogenerated carriers dissipate excess energy in operating perovskite
solar cells is essential for connecting ultrafast photophysics with photovoltaic function and provides design principles for engineering next-generation
cell architectures. Here we use photocurrent-detected two-dimensional electronic spectroscopy (PC-2DES) to resolve energy-dependent carrier relaxation in fully encapsulated, functioning metal halide perovskite
solar cells. By comparing devices with identical architecture but different absorber compositions - MAPbI3, mixed FAMA, and FAPbI3 - we directly follow the redistribution of photoexcited carriers from initially populated high-energy states toward lower-energy band-edge states. The multidimensional photocurrent response reveals a cascade-like intraband cooling process whose rate depends strongly on absorber composition, with the slowest relaxation in MA-based devices, intermediate behaviour in mixed-cation devices, and fastest relaxation in FA-based devices. A reduced kinetic model incorporating
phonon-mediated intraband scattering, supplemented by a phenomenological many-body contribution, captures the main energy-dependent trends. These results establish action-detected multidimensional spectroscopy as a device-level probe of ultrafast energy dissipation and show that subtle changes in perovskite composition can substantially reshape the carrier relaxation pathways that precede charge extraction.
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All authors Edoardo Amarotti, Luca Bolzonello, Qi Shi, Sun-Ho Lee, Torbjörn Pascher, Donatas Zigmantas, Niek van Hulst, Nam-Gyu Park, Tönu Pullerits
Atomic Physics
Magic-wavelength matter-wave interferometry with optical clock states
Jianing Li, Swarup Das, Xinyuan Ma et al. (+4 more)
Optical clocks and atom interferometers provide complementary ways to measure time, motion and
gravity. Combining these capabilities requires matter-wave beam splitters that manipulate different clock states in the same way, so that optical internal energy becomes a controlled degree of freedom rather than a source of systematic phase shifts. Here we realized a dual matter-wave interferometer operating simultaneously on the two states of the $^{88}$Sr optical clock transition, $^1S_0$ and $^3P_0$. The interferometer is driven by Bragg pulses at the 813 nm magic wavelength, for which the two clock states experience the same optical coupling strength. This realizes a common matter-wave beam splitter for atoms whose internal energies differ by an optical excitation. With a sensitivity of 30 mrad, our measurement is consistent with a zero differential phase shift between the two clock-state Mach-Zehnder interferometers, translating to an absence of state-dependent acceleration in free fall at the level of $10^{-5}$. We further used the same interferometer to measure state-dependent optical dipole forces and determine a tune-out wavelength of the metastable $^3P_0$ state to be 478.95(8) nm. These results establish magic-wavelength clock-state interferometry as a platform for differential force sensing, excited-state polarizability metrology and future
quantum-clock tests of
gravity.
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All authors Jianing Li, Swarup Das, Xinyuan Ma, Thomas Zanon-Willette, Shau-Yu Lan, Chang Chi Kwong, David Wilkowski
Quantum Physics
No extension of the Quantum Tensor Product admits a Superposition principle
Vincenzo Fiorentino and Kuntal Sengupta
Textbook
quantum superposition refers to the feature that certain linear combinations of
Hilbert space rays, each representing a valid
quantum state, are themselves valid states. This notion is not operational, and it relies on the underlying
Hilbert space formalism. Recent proposals for experimental tests of indefinite causal order, as well as tests probing the non-classicality of
gravity, pivot on superposition, thereby calling for a theory-independent, operational formalisation of the concept. Here, we define superposition within the framework of Generalised Probabilistic Theories, based on observed statistics in prepare-and-measure experiments. Using this, we formulate three superposition principles to investigate which structural features of
quantum theory carry over to other theories. We study conditions under which these principles carry over from subsystems to their compositions; to this end, we show that the
quantum tensor product emerges as the largest composition rule for
quantum systems respecting all three principles. Furthermore, we show how non-classical features such as
entanglement and preparational uncertainty can be viewed as special forms of superposition.
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Cosmology and Nongalactic Astrophysics
Dianoga simulations of galaxy clusters and groups: Properties of the baryonic components
Stefano Borgani, Alice Damiano, Elena Rasia et al. (+12 more)
We introduce the Dianoga set of cosmological simulations of
galaxy clusters and groups, specifically aimed at studying the impact of the implementation of AGN feedback and
star formation. Using the OpenGadget3 code, we carry out simulations of 28 regions centred on massive
galaxy clusters, and of a cosmological box. This generates a sample of 293
halos with M_{200}> 1.5 x 10^{13} M_{\odot}. Parameters of AGN feedback in the reference implementation were minimally calibrated exclusively to match the local relation between SMBH masses and
stellar masses of host
galaxies. Simulations are compared to observed
galaxy stellar mass function (GSMF),
stellar mass fraction in clusters and groups, BCG masses, scaling relations between ICM/IGM properties and profiles of their thermodynamical properties. In the appendix, we show how results vary as we modify the reference feedback model in six alternative configurations. Our reference model predicts a GSMF in general agreement with observations, albeit overestimated in the high end. BCG
stellar masses and mass fractions are higher than observed in massive clusters, while being closer to observations for groups. Predicted properties of the ICM/IGM are in general agreement with observations, with the core regions of simulated clusters having
entropy and temperature profiles that are slightly less "cool-cored" than observed. A comparison with other implementations of AGN feedback highlights that models including thermal evaporation of the sub-resolution interstellar medium succeed to bring BCG masses and
stellar mass fractions closer to observation, and to increase the cool-coreness of simulated clusters. Our results demonstrate that the details of the interface between AGN energy injection and the sub-resolution interstellar medium model are at least as critical as the total feedback efficiency itself.
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All authors Stefano Borgani, Alice Damiano, Elena Rasia, Tiago Castro, Michela Esposito, Ilaria Marini, Giuseppe Murante, Milena Valentini, Veronica Biffi, Klaus Dolag, Gian Luigi Granato, Antonio Ragagnin, Cinthia Ragone-Figueroa, Alex Saro, Luca Tornatore
High Energy Astrophysical Phenomena
NMMA-Astro-COLIBRI: An Automated Light-Curve Supernovae Classification Service in the Multi-Survey Era
R. Weizmann Kiendrebeogo, Bernardo Cornejo Avila, Sofia Bisero et al. (+6 more)
The surge in publicly available photometric alerts from wide-field surveys requires automated tools for real-time transient classification. We present NMMA–Astro-COLIBRI, an on-demand
Bayesian classification service that couples the
Nuclear-physics and Multi-Messenger Astrophysics (NMMA) inference framework to the Astro-COLIBRI real-time multi-messenger platform. After the detection of an optical transient, if photometry is available, it is quality-filtered. The filtered photometry is fitted by nested sampling against a user-selected model from a library of eleven
supernova templates; results are delivered to every user within minutes. Applying two or more models on the same optical transient, the service reports the corresponding log Bayes factors as a quantitative ranking of competing subtypes. We demonstrate the workflow on SN 2021ugl (ZTF21abotose), a Type IIb
supernova initially mistaken for a kilonova candidate by automated real-time pipelines, comparing competing
supernova and kilonova models. In an early-time configuration using only the first ~ 6 days of photometry in two bands (ZTF g and r), so ten days before spectroscopic confirmation, the empirical Type IIb template recovers the correct classification, favored over both the kilonova template and the kilonova-mimicking shock-cooling model. In the full 47-day, three-band baseline, it again achieves the highest evidence over every competing
supernova and kilonova template. These results highlight the importance of a comprehensive
supernova template library for kilonova discrimination in the multi-survey era.
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All authors R. Weizmann Kiendrebeogo, Bernardo Cornejo Avila, Sofia Bisero, Maxime Cellier, Antoine Ciric, Ilja Jaroschewski, Henrik Rose, Alexandre Saint-Paul, Fabian Schüssler
Strongly Correlated Electrons
Inducing metal-insulator transition via disorder in correlated kagome systems
Qingzhuo Duan, Hongdao Zhuge, Zixuan JIa et al. (+1 more)
The metal-
insulator transition is often accompanied by fascinating
quantum phenomena, including superconducting domes,
antiferromagnetic phase transitions, and
quantum spin liquids. Concurrently, kagome materials are predominantly metallic, necessitating the realization of insulating states to fully exploit their significant potential in logic and optoelectronic device applications. To address this, we investigate the electronic transport and
magnetic properties in correlated kagome systems with hopping disorder using the determinant
quantum Monte Carlo method. Through comprehensive analysis of the kinetic energy, dc conductivity, and density of states at the
Fermi level, we demonstrate that the cooperative interplay between hopping disorder and electron correlations promotes electron localization. Within the
insulator, an increase in the disorder level reduces the Coulomb interaction required for the Mott transition. Additionally, while disorder partially suppresses
antiferromagnetic ordering, it remains insufficient to induce a complete
magnetic transition. Finally, we summarize two schematic regions distinguishing between
antiferromagnetic metal, correlated Anderson
insulator, and disordered Mott
insulator. Our study advances the understanding of metal-
insulator transition in kagome systems by disorder and provides actionable insights for experimental control of these transitions.
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All authors Qingzhuo Duan, Hongdao Zhuge, Zixuan JIa, Tianxing Ma
Materials Science
Multiple topological electronic and phononic quasiparticle excitations in hexagonal TTe (T=Hf, Zr & Ti) crystals
Prakash Pandey and Sudhir K. Pandey
The exploration of topological
fermions and
bosons marks a new chapter in condensed matter physics, unveiling rich and unconventional phenomena. Particularly in
quantum field theory, exotic quasiparticle excitations such as Dirac and Weyl
fermions can serve as direct analogs, and their recent experimental realizations have sparked significant interest in these topological quasiparticles. Although there are various reports on the coexistence of unconventional fermionic quasiparticles such as
spin-1/2 (type-I, type-II, & type-III),
spin-1 (threefold degeneracy), nodal line (type-I, type-II, & type-III) and others, reports on the simultaneous presence of such quasiparticles in both electronic and phononic spectra within a single material remain extremely limited. Herein, using state-of-theart ab initio calculations, we propose the HfTe class of materials, which hosts coexisting type-I, type-II, and type-III Weyl and nodal line phases, along with pseudospin-1/
spin-1 quasiparticles in both electronic and phononic states. We have found that these excitations are robust against variations in exchange-correlation functionals,
spin-orbit coupling, and
lattice parameters, confirming that multiple topological phases in this class of materials are likely to be observed experimentally.
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Plasma Physics
Bright dual-pulse betatron X-ray generation from a laser wakefield accelerator
Bo Guo, Yang Wan, Shuang Liu et al. (+3 more)
Pump-probe experiments using dual ultrashort X-ray pulses provide unique opportunities for resolving non-
equilibrium dynamics initiated by intense X-ray excitation. Betatron radiation from
laser wakefield accelerators offers femtosecond duration, micrometer-scale source size, and intrinsic synchronization with the driving
laser, making it a promising candidate for compact ultrafast X-ray sources. Here, we experimentally demonstrate a high-flux, dual-pulse betatron X-ray source based on a density-tailored gas-mixture target. Two electron bunches are generated within a single
plasma wakefield through ionization-induced and shock-front-triggered injection, subsequently producing twin X-ray pulses. The measured electron spectra and dual-component X-ray angular profiles, together with particle-in-
cell simulations, identify the contributions of the two electron populations to the radiation. The total X-ray
photon yield reaches the level of 10^{10}
photons per shot with a 40-TW
laser system. These results establish a compact, single-stage route toward high-flux dual-pulse betatron sources for laboratory-scale ultrafast X-ray spectroscopy.
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All authors Bo Guo, Yang Wan, Shuang Liu, Xiaonan Ning, Jianfei Hua, Wei Lu
Accelerator Physics
Field deployment of a laser wakefield accelerator for on-site application
Bo Guo, Xiaonan Ning, Dexiang Liu et al. (+7 more)
Successive innovations in particle accelerators have continually expanded the frontiers of scientific discovery.
Laser wakefield accelerators promise to transform science, medicine, and industry, yet moving them from laboratory demonstrations to reliable real-world operation has remained a central, long-standing challenge. Here we report a field-deployable system that produced 100-MeV-class electron beams with 1%-level energy stability during 72 hours of continuous operation and supported routine full-power use throughout a seven-month field trial in an industrial setting. Applied to in situ micro-nondestructive testing, the system generated tens-of-MeV bremsstrahlung X-rays that enabled three-dimensional microtomography of dense materials at sub-50-{\mu}m spatial resolution and revealed 100-{\mu}m-scale internal defects in large composite structures, extending the capabilities beyond those of existing high-energy X-ray sources. These results mark a transition of
laser wakefield acceleration from laboratory proof of concept toward practical deployment in scientific and industrial applications.
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All authors Bo Guo, Xiaonan Ning, Dexiang Liu, Yue Ma, Weiwang Zeng, Mingyuan Wei, Shengtai Wei, Jianfei Hua, Yang Wan, Wei Lu
Optics
The vanishing distance: a depth-range boundary for dynamic wavefront shaping
Hugo Lassiette, Léa Testé, Léa Krafft et al. (+6 more)
Optical imaging and transmission through scattering media conventionally rely on ballistic light, whose power decays exponentially with the optical thickness. Although ballistic light cannot be exploited beyond a certain depth, no simple criterion currently identifies this limit. Therefore, we introduce here the vanishing distance that is defined as the propagation length at which the ballistic power equals the power carried by a single diffuse optical mode. Beyond the vanishing distance, multiply scattered light dominates, which can be harnessed by optical wavefront shaping or by computational reconstructions. We present a simple semi-analytical model for radiance propagation, validated by Monte Carlo simulations and by experiments in both monodisperse and heterogeneous scattering media. From these data, we estimate the vanishing distance and the associated minimum source power. Across representative scattering environments, ballistic light vanishes after about 20 to 40 scattering mean free paths. Unlike the transport mean free path that characterizes the angular randomization of the scattered light, the vanishing distance identifies the loss of the ballistic channel on a modal-power basis. The vanishing distance is thus a two-sided bound: ballistic approaches cannot be efficiently applied beyond it, whereas wavefront shaping of scattered light offers no advantage below it.
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All authors Hugo Lassiette, Léa Testé, Léa Krafft, Geoffrey Maulion, Vincent Michau, Romain Pierrat, Sébastien Popoff, Willem L. Vos, Serge Meimon
Strongly Correlated Electrons
Absence of nontrivial local conserved quantities in a class of $U(1)$-symmetric spin-1 chains
Shunsuke Sengoku and Haruki Watanabe
We prove the absence of nontrivial local conserved quantities in a class of $U(1)$-symmetric
spin-$1$ chains with nearest-neighbor interactions in which some of the quadrupolar couplings vanish, a class that is not covered by previous studies. Applying the technique of Shiraishi to these systems, we show that, for every model in this class on a periodic chain of $N$ sites, there is no $k$-local conserved quantity for any $3\le k\le N/2$. In particular, for a frustration-free
spin-$1$ chain that exhibits spontaneous $U(1)$
symmetry breaking at zero temperature in one spatial dimension, we prove that every local conserved quantity with support up to half of the system size is a linear combination of the identity, the total magnetization $S^z$, and the
Hamiltonian itself. This rigorously establishes that, unlike the Heisenberg ferromagnet, the model admits no local order parameter commuting with the
Hamiltonian, so that its continuous
symmetry breaking is enabled by the frustration-free structure rather than by a conserved order parameter. We also prove the absence of $k$-local conserved quantities for $3\le k\le N/2$ in the periodic Motzkin chain, a frustration-free
spin-$1$ chain closely related to the original Motzkin chain, for which spontaneous $U(1)$
symmetry breaking at zero temperature has also been reported.
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Mathematical Physics · Cross-listed from math.NT
An alternating Mizuno formula, modified gamma functions, and double sine special values
Su Hu and Min-Soo Kim
For $n\ge1$ and $\operatorname{Re}(x_j)>0$, we prove an alternating analogue of Mizuno's product formula: \begin{equation*} \prod\nolimits_{m=0}^{\infty} \left(\prod_{j=1}^{n}(m+x_j)\right)^{(-1)^m} = \frac{(\sqrt{\pi/2})^n} {\prod_{j=1}^{n}\widetilde{\Gamma}(x_j)}, \end{equation*} where $\widetilde{\Gamma}$ is the modified gamma function associated with the alternating Hurwitz
zeta function. The
polynomial factors are regularized using factorwise logarithms, and the formula establishes compatibility between this regularization and
polynomial factorization. Applications include Gaussian and cyclotomic (Kurokawa–Wakayama type) evaluations; the single-factor case recovers the alternating Lerch formula, and a normalized ratio yields Wallis' product. A second group of results concerns an alternating double sine-type function. At nonexceptional positive periods, its positive-integer special values admit finite tangent-product representations. These products define locally meromorphic continuations $F_m$ in the period parameter. For $m\ge2$ and nonzero algebraic parameters, the continued values belong to $\mathbb P^1(\overline{\mathbb Q})$ at rational parameters and are finite, nonzero, and transcendental at nonrational parameters. We determine their orders at rational parameters and distinguish parameter continuation from fixed-period specialization at exceptional parameters. Additional results include Barnes factorizations of multiple alternating gamma functions, a Glaisher–Kinkelin special value, finite-product Stirling-type asymptotics, a symmetric two-parameter form of the known odd-integer multiplication formula, and an odd-scaling distribution relation for the alternating double sine-type function.
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Fluid Dynamics
Roughness-controlled layer in oscillatory turbulent boundary layers over densely packed uniform roughness
Xuchen Liu, Yuan Gao, Yiyong Dong et al. (+1 more)
In coastal wave boundary layers over gravel-scale roughness, with near-bed orbital excursions ten to a hundred times the roughness height, the boundary layer is only a few roughness heights thick. A roughness-controlled layer (RCL) of the steady-flow extent two to five element heights would then leave no room for a logarithmic layer, yet experiments over densely packed marbles recover logarithmic profiles within millimetres of the crests. We resolve this contradiction by re-analysing previous Particle Image Velocimetry (PIV) records with a triple decomposition that separates the marble-locked dispersive motion from the
stochastic turbulence, across eleven wave, current and wave-current conditions. The boundary layer organises into an RCL, a transition region, and a logarithmic profile layer, with the RCL only one to two tenths of a marble diameter deep. This thinness is kinematic: above a periodic bed, the dispersive field decays over a length fixed by the element spacing, so close packing caps the layer at a fraction of a diameter. The layer is destroyed and rebuilt every half-cycle, tracking the near-bed velocity quasi-steadily, while the eddies within it stay locked to the inter-crest gap. Thinness does not imply weakness: within the layer, the dispersive kinetic energy rivals the turbulent kinetic energy, and the dispersive stress matches, near the crests exceeds, the Reynolds stress, showing that separated wakes carry organised momentum. The logarithmic layer survives because the decay length imposed by the packing is far smaller than the boundary-layer thickness, a margin set by the bed geometry rather than by the forcing.
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All authors Xuchen Liu, Yuan Gao, Yiyong Dong, Jing Yuan
Disordered Systems and Neural Networks
Equilibrium and nonequlibrium scaling behaviors of localization transition in a non-Hermitian Aubry-André model with onsite gain and loss
Wen-Jing Yu, Yue-Mei Sun, Xin-Yu Wang et al. (+1 more)
The interplay between non-Hermiticity and localization has attracted considerable interest, yet the driven dynamics of localization transitions in non-Hermitian systems with on-site gain and loss remains largely unexplored. Here we investigate the critical scaling behavior and driven dynamics of the non-Hermitian Aubry-André (AA) model with on-site gain and loss. Through finite-size scaling analyses of the localization length, the inverse participation ratio (IPR), and the energy gap, we extract the critical exponents $\nu = 1.00(2)$, $s = 0.7965(2)$, and $z = 1.999(2)$. These exponents are different from those of both the Hermitian AA model and the nonreciprocal hopping AA model, particularly the IPR exponent $s$, demonstrating that the gain-loss mechanism belongs to a distinct universality class. For the driven dynamics, we focus on the case where the system is initially prepared in a gapless extended state and linearly driven across the critical point. We verify that the finite-time scaling (FTS) framework remains applicable provided that the criterion $z' < r$ is satisfied, where $z' = 1.999(2)$ characterizes the gap closure in the extended phase and $r = z + 1/\nu \approx 2.999$. The predicted FTS scaling forms for the IPR are numerically validated across a wide range of system sizes and driving rates, demonstrating that the unified scaling description can be successfully generalized to the gain-loss type non-Hermitian AA model. Our work not only establishes the gain-loss AA model as a new universality class of localization transitions but also extends the applicability of the FTS framework to non-Hermitian systems with gapless initial states.
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All authors Wen-Jing Yu, Yue-Mei Sun, Xin-Yu Wang, Liang-Jun Zhai
High Energy Astrophysical Phenomena
From Variability to SED Modeling: A Multiwavelength Study of the Neutrino Blazar TXS 0506+056
Shiyu Du, Hanxiao Xia, Jianghua Wu et al. (+1 more)
The blazar TXS 0506+056 is the first source that was reported to be associated with high-energy extragalactic
neutrino events and is one of the major targets for multi-messenger studies. We carried out multi-wavelength optical monitoring of this object on 24 nights in the period from 2018 to 2023. The overall light curves exhibit a dimming trend superposed by some small-amplitude fluctuations, and intraday variability was detected on four nights. Bluer-when-brighter behaviors were observed on both intraday and long timescales and were more pronounced on long timescales, while a weak redder-when-brighter trend was detected on one night. No significant time lags were found between variations at different optical wavelengths. We also retrieved the multi-broadband data from some monitoring programs. The data reveal complex, asynchronous flaring in different wavebands. A cross-correlation analysis shows that the high-energy emission (optical to gamma-ray) is co-spatial and leads the
radio emission by a substantial time of about 800 to 900 days, suggesting that the
radio emission originates from a downstream region of the jet. We performed time-dependent lepto-hadronic modeling of the spectral energy distributions for three representative epochs, the 2017
neutrino-associated
flare, a post-
flare phase, and a deep quiescent state, revealing an
evolution in the radiative properties of the emission regions. The modeling results provide a phenomenological framework for interpreting the long-term multiwavelength behavior of TXS 0506+056 in a multi-messenger context.
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All authors Shiyu Du, Hanxiao Xia, Jianghua Wu, Yue Fang
Materials Science
Growth of Altermagnetic {\alpha}-MnTe Films: Substrate Variation and Surface Modification
M. Dittmar, L. Hirnet, H. Haberkamm et al. (+10 more)
Manganese telluride (MnTe) in its hexagonal {\alpha}-MnTe
crystal structure has evolved as one of the altermagnet workhorse materials. The synthesis of MnTe thin films is highly relevant for both fundamental science and device applications. Here, we report on the epitaxial growth of MnTe thin films and
heterostructures. The films are studied by X-ray and electron diffraction as well as soft X-ray angle-resolved photoemission spectroscopy. We demonstrate the ability to grow high-quality {\alpha}-MnTe on various substrates, ranging from transparent band
insulators, over topological
insulators, metallic transition metal chalcogenides, to the van der Waals ferromagnet Fe$_3$GeTe$_2$. While insulating substrates are useful for transport experiments or optical spectroscopy, metallic topological surface states may trigger spintronic interface effects, such as
spin-orbit torques. Metallic substrates, in general, are highly relevant to avoid charging at the insulating MnTe films in electron spectroscopy or microscopy methods. Lastly,
ferromagnetic substrates will be of interest to control magnetization across the interface. In addition, we discuss the formation of superstructures on the MnTe(0001) surfaces, that emerge directly after growth, upon subsequent tellurium evaporation and after thermal treatment. This will be relevant in further studying the surface
magnetic and electronic structure in {\alpha}-MnTe.
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All authors M. Dittmar, L. Hirnet, H. Haberkamm, F. Beisler, C.-W. Chuang, R. Ganser, P. Kagerer, M.-J. Huang, J. Buck, M. Hoesch, K. Rossnagel, M. Ünzelmann, F. Reinert
Statistical Mechanics
Conditional-path Monte Carlo for rare stochastic dynamics on networks: Details and derivations
Thomas Barthel, Jiazheng Sun and Jhao-Hong Peng
The simulation of rare macroscopic events in
stochastic network dynamics, such as widespread epidemic outbreaks, cascading failures in communication networks, or the escape from metastable states in many-body systems, is severely hindered by methodological challenges like catastrophic rejection rates, weight degeneracy, genealogical correlations, and critical slowing down inherent to standard forward-time
algorithms, splitting methods, and transition-path sampling. Conditional-path Monte Carlo (CPMC) overcomes these limitations by employing non-local Swendsen-Wang-like cluster updates that operate directly on full-system trajectories. Serving as the technical companion to [Sun, Moody, and Barthel, arXiv:2608.16171], this paper provides the rigorous mathematical foundations and algorithmic details underlying the CPMC framework. We formally define the joint path-graph probability weights and derive the transition and uniformization sum rules that guarantee detailed balance. Applying the framework to susceptible-infectious-susceptible (SIS) models, we systematically construct and optimize single-node and edge graph vertex sets specifically designed to prevent lock avalanches and maintain the structural mobility of the epidemic trunk. Furthermore, we detail a dynamic programming scheme to exactly implement complex boundary conditions - including patient-zero and macroscopic outbreak-size constraints - enabling the rejection-free generation of valid trajectories. Finally, we assess the computational complexity of the
algorithm, describe parallelization strategies, and validate CPMC against exact solutions for dynamics on small networks.
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Quantum Physics
Enhanced quantum thermometry near a dissipative phase transition in a driven Kerr cavity
Chayan Purkait and Bimalendu Deb
We investigate
quantum thermometry in a driven–dissipative Kerr cavity coupled to a thermal reservoir. The system exhibits a finite-size precursor of a dissipative phase transition, characterized by a pronounced minimum of the Liouvillian gap and a sharp jump in the steady-state physical observables such as average
photon number at the critical driving strength. We show that this regime leads to strong enhancement of the
quantum Fisher information (QFI) for temperature estimation. Using an effective two-branch description, we show that the enhancement originates from temperature-induced redistribution of the weight factors in
photon number distribution between low- and high-
photon-number branches, which is described by an effective binary Fisher information. By optimizing the coherent drive, the enhanced response persists over an extended low-temperature, low-thermal-occupation regime and yields a favorable relative temperature-uncertainty bound. These results identify finite-size precursors of dissipative phase transitions in Kerr-cavity platforms as useful resources for tunable nonequilibrium
quantum thermometry. We further show that the predicted thermometric enhancement is accessible in a parameter regime compatible with
circuit quantum electrodynamics (
circuit-QED) platforms.
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High Energy Astrophysical Phenomena
Modelling mountains on accreting magnetized neutron stars
T. Brusco, B. Haskell, M. Razzano et al. (+2 more)
Continuous gravitational waves from accreting
neutron stars in Low Mass X-ray Binaries are one of the main targets for current and next generation ground based detectors. In order to select the most promising astrophysical sources, however, reliable predictions for the signals are required, and it is therefore necessary to develop models that consistently account for the combined effects of
magnetic stresses,
accretion-induced heating, and the elastic response of the crust.}{We present a model for computing the quadrupolar deformation, incorporating for the first time the coupled effects of a poloidal
magnetic field, deep crustal heating, and crustal elasticity. Perturbations to the
star's structure driven by the Lorentz force density and by thermally-induced density variations are computed by solving a system of linearised deformation equations in the crust, for which we consider the full elastic response, while the ocean and core treated as barotropic fluids. We identify a threshold
accretion rate whose value depends on crustal microphysics and the superfluid gaps in the core, above which
magnetic stresses and asymmetric
accretion drive deformations of opposite sign, while below this threshold their roles are reversed. The predicted eccentricities reach magnitudes up to $\varepsilon\sim 10^{-11}$, corresponding to characteristic gravitational-wave strains accessible to next-generation detectors such as the Einstein
Telescope or
Cosmic Explorer, but generally below the sensitivity of current LIGO, Virgo and KAGRA interferometers. These results are consistent with the non-detection of continuous gravitational waves from accreting
neutron stars in Low Mass X-ray Binaries in recent observational campaigns, but highlight the need of reliable models to understand the impact of gravitational wave emission in these systems and select relevant targets for future searches.
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All authors T. Brusco, B. Haskell, M. Razzano, M. Bejger, J.L. Zdunik
Quantum Physics
Engineering of Dual Wavelength, Polarization Selective Metalenses in Silicon Carbide
Xiaoying Huang, Ziwei Yang, Konosuke Shimazaki et al. (+7 more)
Spin defects in silicon carbide (SiC) are promising candidates for integrated
quantum photonics, offering long-lived
spin states and near-infrared emission suitable for low-loss photonic integration and fibre-based
quantum communication. However, light extraction from these defects remains challenging due the relatively high refractive index of SiC. Metalenses offer a compact approach to enhance light collection by engineering the wavefront directly at the material interface. Here, we design and fabricate monolithic metalenses from SiC bulk material that simultaneously operate at 860 and 1240 nm, matching with emission from the nitrogen vacancy and silicon vacancy colour centers. By independently engineering the phase response at both wavelengths, the metalens enables collection and polarization manipulation of the emitted light. We further employ the metalenses to demonstrate optically detected
magnetic resonance of both defects simultaneously. These multifunctional metalenses provide a compact optical interface for scalable integrated SiC photonic devices.
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All authors Xiaoying Huang, Ziwei Yang, Konosuke Shimazaki, Kritsana Saego, Otto Cranwell Schaeper, Evan Williams, Dragomir Neshev, Hark Hoe Tan, Igor Aharonovicha, Mehran Kianinia
Superconductivity
Unconventional Pressure Evolution of Spin-Density-Wave State in La$_{3}$Ni$_{2}$O$_{7}$
Xiaoxiang Zhou, Shiyu Xie, Liangxin Qiao et al. (+13 more)
The discovery of pressure-induced high temperature superconductivity in the
bilayer nickelate La$_{3}$Ni$_{2}$O$_{7}$ has raised the question of how its
spin-density-wave (SDW) state evolves toward the superconducting regime. Here, we report a systematic electronic Raman study of La$_{3}$Ni$_{2}$O$_{7}$ single
crystals under hydrostatic pressures up to 16.51 GPa. Both the SDW gap energy and the transition temperature $T_{\mathrm{SDW}}$ show an overall increase with pressure, while the dimensionless coupling ratio 2$\Delta_{\text{SDW}}/(k_{\text{B}}T_{\text{SDW}})$ remains constant around $\sim7.5$, indicating a robust strong-coupling character of SDW state. At the same time, the Raman SDW peak broadens as pressure is applied, indicating a gradual weakening of long-range SDW order. These results reveal an unusual pressure
evolution in which the SDW energy scale is enhanced while the SDW state becomes progressively less coherent, providing spectroscopic constraints on the
magnetic correlations relevant to superconductivity in
bilayer nickelates.
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All authors Xiaoxiang Zhou, Shiyu Xie, Liangxin Qiao, Hengyuan Zhang, Jun Shu, Rui Liu, Mengwu Huo, Deyuan Hu, Hengjie Liu, Chuansheng Hu, Yilin Wang, Ge He, Zeming Qi, Meng Wang, Dong-Lai Feng, Zengyi Du
Computational Physics
Agentic Porting, Construction and Initial Verification and Validation of Libraries within the Open Source Unified TRAnsient Multi-Phase Advanced Reactor simulation Kit (Outram Park) Part I: A Software Engineering Log for Thermal Hydraulics
Theodore Kay Chen Ong and Sicong Xiao
Agentic porting of multiple open-source libraries into Rust, with human in the loop, has been performed for construction of modules within the Open-source Unified TRAnsient Multi-Phase Advanced Reactor simulation Kit (Outram Park). With this new methodology, verification and validation with human expertise, rather than code generation, has become the bottleneck in developing reliable simulation codes. In this work, we present the porting of OpenFOAM libraries into the Outram-Foam Rust libraries, their preliminary verification and validation (V&V) efforts, and their subsequent use in the development of open-source two-phase homogeneous-
equilibrium (HEM) choked-flow solvers for the Thermo-hydraulic AI Multi-Phase INtegrated Emulator System (TAMPINES) libraries within Outram Park, such as tampines-steam-tables. V&V efforts of Outram-Foam show that the cavity and Sod shock tube cases agree with literature values to within acceptable margin. Moreover, the preliminary development of tampines-steam-tables shows good agreement with Moody's HEM charts. Thereafter, the 1D HEM solver, developed agentically, is presented and preliminarily validated against the Edwards blowdown case. Productivity increases were observed with the use of Claude Code, but domain expertise supplied by human experts remains critically required to ensure the generated code can solve the problem effectively. Further work remains to be done in V&V, but the agentic coding methodology described here demonstrates considerable potential to speed up production and development of open-source libraries such as Outram Park.
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Quantum Physics
Characterizing Entanglement in Combinations of Bell States through Superposition and Mixing: An Increase in Entanglement on Introducing Depolarizing, Phase Damping, and Amplitude Damping Noise
Nishant Chaudhari and Jean-François Van Huele
We systematically characterize
quantum entanglement in all sixteen combinations of two-
qubit Bell states across three operational regimes: pure superposition, noiseless mixing, and asymmetric mixing of one noisy and one pure Bell state. For pure superpositions, we calculate the von Neumann
entropy and show that
entanglement depends critically on the relative phase phi between superposed states. For mixed states, we use concurrence C under three physically motivated decoherence channels. The Depolarizing (DP) and Phase Damping (PD) channels are modeled as global, collective operations on the two-
qubit Hilbert space, while Amplitude Damping (AD) is treated as independent local decay on each
qubit, reflecting the asymmetric, energy-dissipating nature of spontaneous emission. A central and counterintuitive result is that increasing noise can raise concurrence in specific parameter regimes across all three channels. We further map the boundary between mathematical
entanglement (C > 0) and operational
quantum non-locality using the Horodecki criterion, finding this boundary to be strongly channel-dependent. Under Phase Damping, the Bell-local
entanglement regime vanishes entirely for identical and same-bases mixtures, meaning any surviving
entanglement guarantees a CHSH violation. Under Depolarizing noise, a large Bell-local region requires mixing probability r > 1/sqrt(2) to recover non-locality at maximum noise. For Amplitude Damping, certain mixtures exhibit a non-monotonic Horodecki parameter M(T): concurrence decreases monotonically with noise, yet the capacity for CHSH violation is lost at intermediate noise levels and restored at high noise, as maximal damping repurifies the noisy branch. These results provide a unified analytical reference for
entanglement and non-locality management across Bell-state combinations and decoherence channels relevant to NISQ architectures.
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Quantum Physics
Noise Resilience of Quantum Support Vector Machine with Selected Feature Maps
Muhammad Ahsan Shakeel, Saad Muzammil, Danyal Tayyub et al. (+1 more)
Gate-level noise degrades the classification accuracy of
Quantum Support Vector Machines (QSVMs) on Noisy Intermediate-Scale
Quantum (NISQ) hardware, and the degree of degradation depends on how classical data is encoded into
quantum states. We tested Z, ZZ, a Pauli, and an amplitude-inspired feature maps under depolarizing, bit-flip, and phase-flip noise channels in $52$ controlled experiments with error probabilities $p =0.01, 0.05, 0.10$, and $0.50$. The amplitude-inspired feature map had $100$% test accuracy up to $p = 0.10$ across all three noise channels, while other feature maps fell to $65$-$90$% under the same noise level and type. The Z feature map was found to be immune to phase-flip noise to a significantly high error rate, a consequence of the commutation relation $[R_Z, Z] = 0$. Entangled
circuit variants produced generalization gaps in train-test sets of up to $17.5$% under noise, whereas the amplitude variants maintained zero gap throughout. These results give practitioners data-driven criteria for a feature map on near-term
quantum hardware.
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All authors Muhammad Ahsan Shakeel, Saad Muzammil, Danyal Tayyub, Muhammad Faryad