Optics
Reducing Turbulence-Induced Outages in a Deployed Terrestrial Free-Space Optical Communication Link via Interleaving
Kadir Gümüş, Vincent van Vliet, Menno van den Hout et al. (+3 more)
We present an experimental study of data interleaving for terrestrial free-space optical communication over a 4.6~km urban testbed. Results demonstrate a two-order-of-magnitude reduction in outage probability. A dependency between measured
turbulence strength, interleaver length, and achievable data rate is revealed, enabling robust system design.
Read the full abstract ▾
All authors Kadir Gümüş, Vincent van Vliet, Menno van den Hout, Thomas Bradley, Eduward Tangdiongga, Chigo Okonkwo
Quantum Physics
3D Ising criticality with Platonic lattice superconducting qubits
Liyang Sui, Hong-Hao Song, Sainan Huai et al. (+13 more)
The three-dimensional (3D) Ising model is a foundational model in statistical physics and critical phenomena, yet its analytical intractability has long impeded the precise determination of universal critical exponents. While high-precision estimates have been obtained through classical numerical methods and conformal bootstrap techniques, a direct
quantum simulation of the 3D Ising criticality remains challenging, requiring nontrivial connectivity, sufficient system size, and high spectral resolution. In this work, assisted by the state-operator correspondence of conformal field theory, we perform a digital
quantum simulation of the 3D Ising critical exponents using a multiply-connected 9-
qubit superconducting
quantum processor with a Platonic
lattice geometry. Employing an extended variational
quantum eigensolver equipped with a phase-based loss function, we variationally prepare the low-energy eigenstates of the transverse-field Ising model on a cubic Platonic
lattice encoded in an 8-
qubit register. The four lowest eigenenergies are extracted via
Fourier-transform analysis and high-precision numerical fitting, agreeing with the exact diagonalization values up to +/- 0.001. The resulting scaling dimension Delta_epsilon = 1.5850 and critical exponent nu = 0.7067 match well with theory.
Read the full abstract ▾
All authors Liyang Sui, Hong-Hao Song, Sainan Huai, Yufan Li, Zhiwen Zong, Kunliang Bu, Xiaopei Yang, Xingrui Liu, Wenyan Jin, Bowen Chen, Xutao Zhang, Jianlan Wu, Yicong Zheng, Shengyu Zhang, Gang v. Chen, Yi Yin
Astrophysics of Galaxies
Optically Invisible Galaxies at Cosmic Noon and beyond with JWST/UNCOVER
Pralay Biswas, Rashi Jain and Yogesh Wadadekar
The traditional selection bias in high-
redshift galaxy surveys toward rest-frame ultraviolet emission has constrained our understanding of the high-
redshift universe by systematically excluding optically faint (observer-frame)
galaxies. Utilising JWST UNCOVER and MegaScience data of the Abell 2744 cluster field, we identify 113 high-
redshift ($z > 2$) and 94 low-
redshift ($z < 2$) HST-dark
galaxies using a red $1.50-3.56 \ \mu$m color criterion. Their physical properties were derived using multiwavelength photometry from 20 JWST/NIRCam and 7 HST filters. Unlike classical submillimeter and Spitzer-selected HST-dark
galaxies that primarily identify the most massive, dusty, highly
star-forming
galaxies, our study uncovers a moderately dusty population across a significantly broader range of
stellar mass and
star-formation rate. Leveraging gravitational magnification and ultra-deep JWST imaging, we found HST-dark
galaxies with a
stellar mass as low as $10^{7.5}$ at $z>2$. These
galaxies have smaller sizes and follow the
star-forming main sequence. Our analysis reveals a prominent peak in the
Star Formation Rate Density at $z \approx 4.5$ ($9.89^{+6.93}_{-4.34} \times 10^{-3} \, M_{\odot} \, \text{yr}^{-1} \, \text{Mpc}^{-3}$). We also characterise a sub-population at $z < 2$ of Highly Extincted Low-Mass analogues with extremely low
stellar masses (median $\log M_{\star}/M_{\odot} \approx 7.10$) and high
dust extinction (median $A_V \approx 1.97$ mag). Our sample demonstrates the unique power of JWST to reveal this previously missing
galaxy population and to provide a more complete census of
galaxies in the high-z universe.
Read the full abstract ▾
Materials Science
High-entropy Fe$_2$VAl-based thermoelectric modules with improved conversion efficiency
Michael Parzer, Geoffrey Roy, Fabian Garmroudi et al. (+4 more)
Thermoelectric (TE) materials enable the direct conversion of heat into electricity and are attractive for sustainable energy applications. For practical deployment, TE materials must combine high efficiency with low cost, non-toxicity, and scalability. In this work, we optimize the TE performance of low-cost and robust Fe$_2$VAl-based full-Heusler compounds through high-
entropy engineering: a synergistic combination of heavy-element doping and controlled off-stoichiometry results in substitutional disorder on all
lattice sites, triggering one of the lowest
lattice thermal conductivities, $\kappa_\text{L}\sim2.3$ W m$^{-1}$ K$^{-1}$, reported so far for full-Heusler systems. The resulting materials exhibit improved values of the average figure of merit $zT_\text{ave}\approx 0.3$ from $300-500$ K. To demonstrate reproducibility and technological relevance, a full TE module (TEM) based on the optimized
alloys was fabricated and characterized. Scaled-up material batches were synthesized by hot pressing, exhibiting TE properties in excellent agreement with laboratory-scale samples, with only slightly increased resistivities in absence of post-annealing treatments. Owing to the excellent mechanical workability of Fe$_2$VAl-based materials, the TEM legs were directly brazed onto copper electrodes, enabling robust module fabrication. A ($6\times 6$)-leg TEM was assembled and systematically characterized. The device exhibits the highest output power and one of the highest conversion efficiencies reported to date for Fe$_2$VAl-based generators over the broad temperature range of $300-673$ K, underscoring the potential of this material system for scalable TE energy harvesting.
Read the full abstract ▾
All authors Michael Parzer, Geoffrey Roy, Fabian Garmroudi, Pawel Ziolkowski, Thomas Konegger, Ernst Bauer, Pascal J. Jacques
Materials Science · Cross-listed from math.NA
Phase-field digital image correlation for integrated displacement and damage measurements
Dingxiang Zhu and Ye Lu
This work presents a novel digital image correlation (DIC) framework for full-field measurements of displacement, strain, and damage, based on a phase field (PF) approach. The idea is to take advantage of the ability of the PF method to track complex crack morphologies and to provide a natural way in DIC to perform damage and crack measurements from experimental speckle images, in addition to displacement and strain fields. Moreover, incorporating the damage variable into DIC can improve the displacement accuracy near the crack tip, and can avoid the need of user-defined masks when dealing with cracked samples, which is advantageous when cracks become complex and the manual application of masks becomes challenging. The theoretical formulation of the proposed framework, namely PF-DIC, was presented in detail in the paper, along with a finite element implementation. Numerical examples have demonstrated the capability of the proposed PF-DIC in terms of capturing different types of cracks while providing similar measurement accuracy to that of masked DIC. Additionally, it is shown that the PF-DIC can be easily adapted to selectively identify critical cracks under specific loading conditions or mechanisms for damage assessment and diagnostic purposes. The proposed DIC framework can be used to characterize material defects, support structural health monitoring, and enable a potential unification of PF simulations and experimental fracture measurements
Read the full abstract ▾
Statistical Mechanics
Exact solution of the Glauber-Ising model on the finite-length semi-open chain
Malte Henkel
The exact time-space correlation function of the $1D$ Glauber-Ising model, quenched to temperature $T=0$ and on a semi-open
lattice of finite size $N$, is obtained. This also allows to deduce the exact empty-interval probability of the dual $1D$ coagulation-
diffusion process on a periodic finite ring and to reproduce the long-time decay of the particle concentration. These results are consistent with the generic expectations of dynamical finite-size scaling theory.
Read the full abstract ▾
Cosmology and Nongalactic Astrophysics
The cosmic tetrarchy: four estimators breaking the assumption degeneracy in cosmological distance tensions
Matteo Martinelli and Domenico Sapone
The origin of cosmological distance tensions remains a central open question in precision cosmology, complicated by the fact that most consistency tests between
datasets cannot isolate which physical assumption is responsible for an observed discrepancy. We address this by reformulating the standard cosmological framework as a single null test: the requirement that the dimensionless sound-horizon ratio $r_{\rm d}/r^{\rm fid}_{\rm d}$ be one
redshift-independent number. We show that this test admits four complementary measurements, obtained by combining
Baryon Acoustic Oscillation (BAO) data with either Type Ia
supernovae (SNIa) or
cosmic chronometers (CC), in either the transverse or the radial direction. The four channels rely on distinct subsets of physical assumptions — distance-ladder calibration, the distance duality relation, spatial flatness, and the standard-ruler picture — and one of them, the radial CC-anchored channel, requires none and serves as the natural reference of the framework. The pattern of agreement or disagreement among the four therefore localises the assumption responsible for any observed tension. We refer to this fourfold decomposition as the
cosmic tetrarchy and evaluate it on DESI DR2 BAO data combined with Pantheon+ and
cosmic chronometers, using both a binned analysis with full analytic covariance propagation and a non-parametric Gaussian Process reconstruction. We find that current data are compatible with a single,
redshift-independent sound-horizon scale; when comparing the different
estimators, we find hints of discrepancies between those based on SNIa and those relying on CC, although with a lack of statistical significance, which might hint to a manifestation of the Hubble tension or to the breaking of assumptions such as the distance duality relation.
Read the full abstract ▾
Optics
Divergence of Light Wave Amplitudes in an Interface Layer at Critical Conditions
Reinhard Eduard Sigel
The amplitudes of light modes in a homogeneous interface layer are investigated around the critical conditions (CC) in a total reflection geometry. CC occur when the normal wave vector vanishes; the resulting divergence upon variation of the angle of incidence is characterized by a critical exponent -0.5. Absorption replaces the divergence with a finite peak whose width and height are derived analytically. The high relevance of the amplification for Evanescent Wave Dynamic Light Scattering (EWDLS) is demonstrated using published experimental data. The relation to surface plasmon resonance (SPR) is briefly discussed. An outlook connects the amplitude divergence to a critical analysis of the Distorted Wave Born Approximation (DWBA) presented in a companion paper.
Read the full abstract ▾
Medical Physics · Cross-listed from eess.IV
Conditioning Deep Anatomical Prior Knowledge for Reconstruction of Multispectral Optoacoustic Tomography Images
Sarah Franceschin, Lukas Imanuel Scheel-Platz, Philipp Haim et al. (+3 more)
Accurately delineating tissues and reconstructing their chromophore compositions from Multispectral Optoacoustic
Tomography (MSOT) images is a key challenge in optoacoustic imaging. The difficulty arises because light fluence distributions within tissue intrinsically depend on spectral optical properties, making the inverse problem inherently ill-posed. Currently, there is a lack of studies leveraging a priori probabilistic anatomical knowledge to guide tissue
segmentation and infer chromophore composition. Moreover, most current studies address these two tasks sequentially, which can result in errors accumulating. through the process. To address these issues, we present Anatomical Priors for Reconstruction of Optoacoustic
Tomography (APRECOT), a method that leverages probabilistic models of anatomical structures and tissue properties, to enable simultaneous
segmentation of tissues and reconstruction of their bulk chromophore compositions. In this proof-of-concept using in-silico data, we show that incorporating probabilistic anatomical context strongly improves the accuracy of bulk chromophore concentration estimation compared to reference methods that do not use any anatomical context or use sequential strategies. This work represents an essential step towards an MSOT imaging mode that directly provides clinically relevant information, such as imaging tissue oxygenation dynamics or disease-related changes in tissue composition.
Read the full abstract ▾
All authors Sarah Franceschin, Lukas Imanuel Scheel-Platz, Philipp Haim, Guillaume Zahnd, Vasilis Ntziachristos, Dominik Jüstel
Astrophysics of Galaxies
Oxygen in the protostellar clump OMC-2 FIR4
Jorma Harju, Paola Caselli, Rolf Güsten et al. (+6 more)
Atomic oxygen (OI), OH, H2O, and CO are the main carriers of oxygen in dense interstellar gas and important coolants of shocks associated with protostellar
outflows. We determine the relative abundances of these species in the warm inner parts of the protostellar clump OMC-2 FIR4 in Orion A. The clump contains several young
stellar objects. The upGREAT receiver including the High Frequency Array (HFA, operating at 4.74 THz, 63 micron) onboard the Stratospheric Observatory for Far-Infrared Astronomy (SOFIA) was used to observe OMC-2 FIR4 in the lines of OI, OH, OD, HDO, and CO. Additional HDO lines were observed with the Atacama Pathfinder Experiment (APEX). Archival H2O and CO spectra observed by the Herschel satellite were included in the analysis. The observed lines were reasonably well reproduced by an expanding spherical shell model. The OI spectrum at 63 micron towards OMC-2 FIR4 is dominated by a broad line component, on top of which medium-wide and narrow line components can be discerned. The same components are present in the OH, H2O, and high-J CO spectra towards this source. We find that OI is more abundant than H2O in the shocked gas. In the broad line component, the following abundance ratios are derived: OI/H2O ~ 700, OI/OH ~ 300, OI/CO ~ 4. The high relative abundance of atomic oxygen there suggests an origin in dissociative J-shocks that are associated with strong ultraviolet radiation. The OI/CO ratio decreases below unity in the components with a smaller velocity dispersion, and these components also have higher abundances of H2O than the broad line component, although remaining below that of CO. The HDO/H2O ratio in the low-velocity components corresponds to the average ratio in the icy mantles of
dust grains, and the presence of water there could also be understood in terms of sublimation without invoking high-temperature chemistry.
Read the full abstract ▾
All authors Jorma Harju, Paola Caselli, Rolf Güsten, Helmut Wiesemeyer, Sandra Brünken, Marc Mertens, Olli Sipilä, Jürgen Stutzki, Friedrich Wyrowski
Physics Education
Students' Validation Criteria for AI-Generated Physics Solutions
Álvaro Suárez and Richard González
A physics solution can be clear without being valid. This distinction becomes important when students read AI-generated solutions that appear coherent but still require physical and mathematical checking. We examined how pre-service physics teachers in a calculus-based introductory electromagnetism course evaluated AI-generated solutions to a charged-rod electric-field problem after attempting the problem themselves. Although the AI-generated solutions analyzed were correct, no student accepted a response as valid after a first reading. Students who had solved the problem fully or in part could examine the responses using physical and mathematical criteria, while others withheld acceptance because they could not follow the mathematical development. These results suggest that, in physics instruction, AI-generated solutions should be treated less as answers to be accepted or rejected and more as worked-out responses that students learn to reconstruct, question, and test.
Read the full abstract ▾
Quantum Physics
Physically Motivated Ansatz for Open Fermionic Systems on Quantum Computer
Yi Liu, Xiaopeng Li, Zhen Liu et al. (+1 more)
Determining non-
equilibrium steady states (NESS) of open fermionic systems is a fundamental problem akin to finding ground states of closed systems. To address this, variational
quantum algorithms can be used to solve the Lindblad master equation, much like the Schrödinger equation, yet ansatz design for NESS remains challenging. Existing approaches rely mostly on hardware-efficient ansätze (HEA), which suffer from the barren plateau problem. Here, we introduce a physically motivated ansatz named NE-UCC. Numerical simulations demonstrate that NE-UCC reliably converges to the steady state even in strongly correlated regimes far from
equilibrium, reducing the infidelity by up to ten orders of magnitude compared to HEA. Furthermore, NE-UCC facilitates the exploration of excited eigenmodes with specific
symmetries.
Read the full abstract ▾
All authors Yi Liu, Xiaopeng Li, Zhen Liu, Zhenyu Li
Physics Education
AI as a Partner in Learning about, Doing, and Engaging with Science: Vigilance as the Key to Productive Augmentation
Marcus Kubsch
AI has become a partner in how people learn about, do, and engage with science, and the partnership takes three forms: a scientist works with a co-scientist whose output must be checked; a member of the public looks something up to decide whether a diet works or whether to fit
solar panels; and a student takes up an inquiry with AI in a science class. Across all three, one thing decides whether the partnership helps or harms: whether the human evaluates what the AI returns or takes it on trust. I argue that this evaluation – epistemic vigilance calibrated to how far a fallible source can be trusted – is, given adequate prior knowledge, the binding constraint on productive augmentation. You can hand the AI a great deal precisely because you stay vigilant; vigilance makes generative partnership safe, so it licenses augmentation rather than restricting it. Vigilance is already invoked in science education but under-specified for the AI case; I specify its components, the mechanism tying it to learning, and a way to measure it without soliciting the evaluation it is meant to detect. What is distinctive is that the machine's fluent, confident prose reads as trustworthy whether or not it is, so its surface works against the human evaluating it. The argument bears hardest on education: the integrated conceptual knowledge instruction aims to foster forms only under deep processing, and vigilance sets how deeply a claim is processed, so it is the precondition for learning with AI. The design factors the field reports matter through whether they engage the learner's evaluation; none works around it. Untested is vigilance as a measured disposition, above all where the AI is confidently wrong. Because it is unevenly distributed, integrating AI uniformly is likely to widen the gap between better- and less-prepared students. I close on how it might be built by fading support as the learner takes over.
Read the full abstract ▾
High Energy Astrophysical Phenomena
From Morphology to Variability: Radiative Cooling Effects on Horizon-Scale Polarization in Two-Temperature GRMHD Simulations
Jane SiNan Long, Akhil Uniyal, Mingyuan Zhang et al. (+4 more)
Polarization signatures provide a new window to investigate the effects of radiative cooling in the horizon-scale
accretion flows. Morphology and variability of polarization offer quantifiable diagnostics of how cooling modifies the polarised emission from two-temperature GRMHD simulations. We find that cooling enhances the effective Faraday depth, leading to stronger large-scale Faraday scrambling, particularly at higher
accretion rates. In contrast, depolarization associated with higher-order
photons is comparable between cooling and non-cooling models. Radiative cooling also increases the intrinsic asymmetry in both the ring structure and the polarization pattern. This effect is quantified by enhanced power in non-axisymmetric azimuthal modes ($\beta_m$, $m \neq 2$) relative to the dominant quadrupolar component $\beta_2$. The increased asymmetry is directly linked to stronger temporal variability of the polarization angle $\angle\beta_2$, including frequent sign reversals that are absent in non-cooling models. The radial profile of $\angle \beta_2$ further localizes the physical origin of these effects, distinguishing regions dominated by Faraday rotation from those influenced by
photon ring contributions, and providing a clear separation between cooling and non-cooling cases. Additional tests including a non-thermal electron population indicate that the polarization structure at 230 GHz is largely insensitive to the detailed form of the electron distribution functions. Our results demonstrate that horizon-scale polarization asymmetry, variability, and radial structure encode robust signatures of radiative cooling. These findings highlight the diagnostic power of time-resolved polarimetry and high-resolution imaging for constraining radiative processes in black hole
accretion flows with EHT-like observations.
Read the full abstract ▾
All authors Jane SiNan Long, Akhil Uniyal, Mingyuan Zhang, Yosuke Mizuno, Ziri Younsi, Christian M. Fromm, Kinwah Wu
Materials Science
Data-Driven Micromechanical Characterization and Mapping of Shale Rocks Using High Speed Nanoindentation
Shaziya Ahmed Banu, Xukai Zhang, Samah A. Mahgoub et al. (+4 more)
This study investigates the potential of high-speed nanoindentation in collaboration with data analytics and phase volume fractions to achieve micromechanical characterization of heterogeneous rocks. While micromechanical characterization can be performed using mechanical testing alone, integrating chemical analysis-such as elemental mapping techniques-provides essential phase identification. This enables more accurate interpretation of phase-specific mechanical properties. However, incorporating chemical analysis increases the complexity of the process. Hence, this study proposes data-driven micromechanical characterization and mapping of heterogeneous rocks based primarily on mechanical data and limited dependence on chemical analysis. In this study, Mancos shale rock is analyzed using high-speed nanoindentation to determine the mechanical properties at the microscale. Subsequently, a suite of unsupervised statistical learning techniques, such as Uniform
Manifold Approximation and Projection (UMAP) with k-means Clustering, Gaussian Mixture Model (GMM), Dirichlet Process Mixture Model (DPMM), and Density-Based Spatial Clustering of Applications with Noise (DBSCAN), are applied to the nanoindentation data. Additionally, an automated image processing and
segmentation technique was developed and tested. The results from each technique have been systematically compared against the conventional chemo-mechanical approach using two metrics: weighted error and spatial error. Based on the results, UMAP with k-means clustering is the most appropriate technique, while DBSCAN, DPMM, and image
segmentation techniques are more suitable as secondary approaches. This study demonstrates the capability of high-speed nanoindentation combined with machine learning techniques for micromechanical characterization with reduced analytical complexity and improved workflow efficiency.
Read the full abstract ▾
All authors Shaziya Ahmed Banu, Xukai Zhang, Samah A. Mahgoub, Christopher C. Walker, George M. Pharr, Arash Noshadravan, Sara Abedi
High Energy Astrophysical Phenomena
Detection and luminosity-dependent evolution of the high-energy hump in the Be/X-ray pulsar 1A 1118-61
Alexander Salganik, Sergey S. Tsygankov, Sergey V. Molkov et al. (+12 more)
Context. Accreting X-ray
pulsars exhibit strong luminosity-dependent changes in their broad-band spectra. At high luminosities, their spectra are usually described by a power-law continuum with a high-energy cutoff, whereas low-luminosity observations have revealed a two-hump spectral morphology. Aims. We aim to trace the luminosity-dependent spectral
evolution of the Be/X-ray
pulsar 1A 1118-61 and to constrain the luminosity range over which the high-energy hump becomes clearly distinguishable. Methods. We use dense SRG/ART-XC and Insight-HXMT monitoring, together with three broad-band NuSTAR observations of 1A 1118-61 obtained during its 2026 outburst, to trace the luminosity-dependent
evolution of the spectral shape. The ART-XC data follow the decay from a peak luminosity of $\simeq7\times10^{37}$ erg s$^{-1}$ to a low-luminosity plateau at $\simeq(3$-$8)\times10^{35}$ erg s$^{-1}$ in the 4-35 keV band, while the NuSTAR observations provide broad-band spectra during the bright phase, the decline, and the plateau. We describe the continuum with a phenomenological two-component Comptonization model. Results. As the source faded, the broad-band continuum developed a distinct high-energy hump, giving rise to a two-hump morphology with broad maxima near $\sim$10 keV and $\sim$30-40 keV. The ART-XC monitoring constrains the transition to this morphology to $L_{4-35}\simeq(0.8$-$1.8)\times10^{36}$ erg s$^{-1}$. We also find a break in the luminosity dependence of the flux ratio between the two continuum humps around $L_{4-35}\sim10^{37}$ erg s$^{-1}$. A cyclotron line at $\simeq55$ keV is detected in the high-energy hump, with no significant luminosity dependence of its centroid energy. We discuss this behavior in the context of resonant interactions in the magnetized
accretion flow.
Read the full abstract ▾
All authors Alexander Salganik, Sergey S. Tsygankov, Sergey V. Molkov, Hua Xiao, QingChang Zhao, Long Ji, Alexander A. Mushtukov, Igor Yu. Lapshov, Alexander A. Lutovinov, Alexey Yu. Tkachenko, Hua Feng, Shuang-Nan Zhang, Xiao-Bo Li, Shu Zhang, Juri Poutanen
Astrophysics of Galaxies
A HINSA view of cosmic-ray ionization in IC 348 and NGC 1333: evidence for a strong low-energy cosmic-ray disparity
Gan Luo, Marco Padovani, Daniele Galli et al. (+5 more)
The
cosmic-ray ionization rate (CRIR) is one of the fundamental parameters influencing the chemical and dynamical
evolution of molecular clouds. Although observations in recent years have revealed high CRIR values in massive
star-forming regions and in the vicinity of protostars, the sources and acceleration mechanisms of
cosmic rays remain uncertain. In this work, we present our new estimates of CRIR using the HI narrow self-absorption (HINSA) technique towards two nearby low-mass
star-forming clouds, IC 348 and NGC 1333. In both clouds, the CRIR decreases with increasing H$_2$ column density, but IC 348 exhibits values that are roughly an order of magnitude higher than those in NGC 1333. To interpret this contrast, we model the low-energy spectrum of CRs in a finite slab attenuation framework, using additional constraints from the high-energy CR spectrum inferred from
Fermi $\gamma$-ray observations. The best-fit spectra reproduce the observed CRIR profiles and the contrast between IC 348 and NGC 1333 suggests an order of magnitude difference in low-energy CR populations, likely originating from local acceleration sources beyond protostars (e.g.,
stellar-wind termination shocks), and partly from the same sources responsible for the GeV $\gamma$-ray excess. Although uncertainties in cloud structure and gas density may affect the absolute CRIR values, they do not erase the pronounced disparity between the two regions.
Read the full abstract ▾
All authors Gan Luo, Marco Padovani, Daniele Galli, Thomas G. Bisbas, Brandt A. L. Gaches, Di Li, Marko Krčo, Ningyu Tang
Statistical Mechanics
The Riviera model with egoistical settlers
P. L. Krapivsky
The Riviera model mimics a densifying settlement along the coastline. In the
lattice version, houses are built sequentially in empty sites with the constraint that every newly built house has at least one empty neighboring site. The distribution of clusters of adjacent houses does not obey a closed set of evolutionary equations, but the void-cluster-void distribution does. We compute the latter and extract the cluster distribution from it. In the jammed state, when all voids have length one, the cluster distribution takes a simple closed form and exhibits factorial decay with cluster size. For finite systems, we use a static approach that directly analyzes jammed states. If the coastline is a finite segment, we determine the statistics of the number of empty sites in the jammed state (the average, variance, and higher cumulants). We also study a continuum version in which houses are built along the line, subject to a minimum separation from at least one neighboring house.
Read the full abstract ▾
Exactly Solvable and Integrable Systems
Pole Dynamics, Linearization, and Perturbations of the Satsuma–Mimura Equation
Yan Lingjuan, Hu Xingbiao, Liu Yajie et al. (+1 more)
This paper investigates the pole dynamics and perturbation theory of algebraic
soliton solutions associated with the Satsuma–Mimura (SM) equation. First, we give a qualitative analysis of the pole system associated with algebraic
soliton solutions, thereby completing a point left open in \cite{Yan_2025}. We then examine three perturbations of the SM equation. The $u_x$ perturbation preserves exact linearizability and leads to an explicit shifted algebraic
soliton solution. The $u_{xx}$ perturbation can be reduced to the unperturbed SM equation by a scaling transformation, which yields the corresponding pole asymptotics and
soliton profile. For the genuinely nontrivial $Hu_{xx}$ perturbation, we derive the first-order perturbation equations and present a short-time numerical simulation based on an explicit Euler discretization. These results clarify how algebraic
solitons of the SM equation respond to different perturbative mechanisms.
Read the full abstract ▾
All authors Yan Lingjuan, Hu Xingbiao, Liu Yajie, Zhang Yingnan
Earth and Planetary Astrophysics
Deepak Bisht, Christiane Helling, David Gobrecht et al. (+6 more)
This study investigates the thermal stability and absorption of metal
oxide clusters in exoplanetary atmospheres. Utilizing our thermochemical data, we analyze eight distinct cluster families: magnesium
oxide (MgO), silicon monoxide (SiO), titanium monoxide (TiO), vanadium monoxide (VO), titanium dioxide (TiO$_2$), vanadium dioxide (VO$_2$), aluminum
oxide (Al$_2$O$_3$), and vanadium pentoxide (V$_2$O$_5$).
Equilibrium cluster populations as a function of gas temperature and pressure reveal distinct stability regimes. Under
solar elemental abundances, (TiO$_2$)$\rm\rm_N$ and (Al$_2$O$_3$)$\rm_N$ are favored at higher temperatures, while (MgO)$\rm_N$ and (SiO)$\rm_N$ dominate at lower temperatures. Computed absorption spectra exhibit strong size- and composition-dependent absorption features in the mid-infrared (8–50~$\mu$m), many of which fall within the wavelength range accessible to JWST/MIRI. We further coupled cluster thermodynamics with 3D general circulation model (GCM) outputs to investigate the cluster stability across the ultra-hot Jupiters (UHJs) WASP-121 b and WASP-18 b, the hot Jupiter (HJ) WASP-39 b, and the warm Jupiter (WJ) WASP-69 b. In WASP-121 b and WASP-18 b, extreme dayside temperatures suppress large-cluster stability, yielding atmospheres dominated by metal ions at low pressures and neutral metals at depth, with limited cluster survival on the nightside and morning terminator. In WASP-39 b, larger clusters are not thermochemically favoured despite the enhanced
metallicity; instead,
equilibrium chemistry stabilises smaller species, with only TiO showing a tendency toward stable larger cluster forms, likely due to its open d-orbitals. In contrast, WASP-69 b favors the formation of larger metal
oxide clusters across an extended pressure range, highlighting WJs as a favorable environment for metal
oxide cluster stability.
Read the full abstract ▾
All authors Deepak Bisht, Christiane Helling, David Gobrecht, Ludmila Carone, Helena Lecoq-Molinos, Peter Woitke, Markus Aichhorn, Jan Philip Sindel, Amit Reza
Statistical Mechanics
Extracting Boundary Conformal Data from Periodic Non-Hermitian Critical Chains
Yifan Liu, Haruki Shimizu, Dongchang Liu et al. (+1 more)
Boundary conformal field theory (BCFT) contains universal data that are usually accessed microscopically by imposing spatial boundaries on the
lattice. In non-Hermitian many-body systems, however, changing boundary conditions can qualitatively reorganize spectra and eigenstates, and their boundary criticality remains elusive. Here, we introduce a periodic-chain spectroscopy to extract universal boundary quantities, such as the Affleck-Ludwig $g$-factor, directly from non-Hermitian bulk-critical
quantum chains, avoiding the need to engineer microscopic open boundaries and circumventing subtle boundary effects in non-Hermitian systems. We illustrate our method with a $\mathcal{PT}$-symmetric Ising realization of the real nonunitary Yang-Lee CFT and reveal a universal negative excited-to-ground ratio, which has no counterpart in
unitary critical theories and provides a microscopic signature of nonunitarity. For the genuinely complex fixed points of the non-Hermitian five-state Potts chain, we extract intrinsically complex boundary coefficients, verify the exact Kramers-Wannier duality relation, and select the consistent analytic-continuation branch of the boundary states. Our results establish a route to nonunitary BCFT universal data using only knowledge of the bulk critical system, opening a window into non-Hermitian boundary criticality.
Read the full abstract ▾
All authors Yifan Liu, Haruki Shimizu, Dongchang Liu, Kohei Kawabata
Quantum Physics
Quantum Nonlocal Games on Graph Ensembles
Joshua Tucker, Chris Weeks, Peter Drmota et al. (+11 more)
Quantum entanglement is one of the most striking discoveries in all of science. This effect allows, for instance, two spatially separated
agents to coordinate their actions, without communication, to an extent that is both counter-intuitive, and provably impossible by any other physical means. A recently discovered example is that of mobile
agents (players) performing spatial coordination tasks such as rendezvous, where the
agents aim to meet on a network without communication. Until now, demonstrations of this advantage have relied on highly idealized conditions:
agents are assumed to have complete knowledge of the topography, and experiments have been restricted to simulations using data generated by
qubits within a single
quantum processor. Here we address both limitations by developing a theory for graph ensembles that capture topographical uncertainty and by experimentally demonstrating the advantage in rendezvous scenarios between physically separated ion-trap systems with access to remote
entanglement. Moreover, we simulate a broader set of problems on superconducting hardware. Surprisingly, when players are given the ability to gather more local information the
quantum advantage increases – a feat impossible by classical means. Our findings establish a concrete route toward practical
quantum advantages in motion coordination problems. More broadly, they point to a new way of using portable
quantum devices to enhance collective decision-making in uncertain environments.
Read the full abstract ▾
All authors Joshua Tucker, Chris Weeks, Peter Drmota, Ellis M. Ainley, Ayush Agrawal, Adam R. Martinez, Erin Malinowski, Jacob A. Blackmore, David P. Nadlinger, Gabriel Araneda, David M. Lucas, Carlos A. Perez-Delgado, Paul Strange, Jorge Quintanilla
Solar and Stellar Astrophysics
KRONOS II: Solar-like Umbra and Penumbra Properties on the Young Sun V1298~Tau
Matthew M. Murphy, Adina D. Feinstein, Meir E. Schochet et al. (+14 more)
Transiting
exoplanets provide a unique laboratory for studying
stellar surface heterogeneities via starspot or facular occultations. When observed at multiple wavelengths, this configuration enables spectroscopic characterization of spot thermal contrasts, distributions, and morphology. In this work, we leverage JWST NIRISS/SOSS transit observations of the 20–30~Myr
planets V1298~Tau~bcd to study the surface properties of their
solar analog host
star V1298~Tau. We identify 14 starspot crossing events across two visits. We derive $0.8-2.8\mu$m starspot contrast spectra and demonstrate the contrasts can only be explained when accounting for the umbral and penumbral components of the starspots, robust to which
stellar model grid is assumed. The spot temperatures are broadly consistent between visits, suggesting that V1298~Tau ($T_\mathrm{phot}=4866\pm33$\,K) has starspots with $T_{\mathrm{umbra}}$ = 3300–3600\,K umbrae and $T_{\mathrm{penumbra}}$ = 4400–4600\,K penumbrae, and are $\sim$25–30% umbrae by area. The differences between these spot components and the
stellar photosphere are consistent with sunspots. Additionally, the relation between the spot contrast and the ratio of umbral to penumbral area is similar to that of the Sun. Combining these JWST observations with long baseline multi-band photometry from the Las Cumbres Observatory, we also estimated the global unocculted spot distribution, revealing at least 5 additional large unocculted active regions. Altogether, these measurements suggest that while the total spot coverage evolves in time, the relative temperatures of surface heterogeneities on Sun-like
stars may be consistent throughout their lifetimes. Furthermore, these results demonstrate that JWST
exoplanet transit observations can be useful for starspot substructure characterization.
Read the full abstract ▾
All authors Matthew M. Murphy, Adina D. Feinstein, Meir E. Schochet, Benjamin V. Rackham, Luis Welbanks, Darryl Z. Seligman, Girish M. Duvvuri, Eva-Maria Ahrer, John H. Livingston, Saugata Barat, Jean-Michel Désert, Rafael Luque, Catriona Murray, Matthew C. Nixon, Sydney Petz, Michael Radica, Hinna Shivkumar
High Energy Physics (Phenomenology)
QCD-like theories at next-to-next-to-leading order with $N_F=2$ non-degenerate fermions
Johan Bijnens and Daniil Krichevskiy
QCD-like theories with $N_F=2$
fermion flavours in real and pseudoreal representations are studied within
Chiral Perturbation Theory. For the pseudoreal
symmetry-breaking pattern $SU(4)/Sp(4)$, the reduced NLO Lagrangian is derived. The NLO and NNLO corrections to the pion masses, decay constants, and
vacuum condensates are calculated for non-degenerate
fermion masses, extending previous results obtained for degenerate masses and for the non-degenerate case at NLO. Using the available spectroscopic and scattering
lattice data for the $Sp(N_c=4)$ gauge theory with two
fermion flavours, fits of the NLO low-energy constants are performed at NNLO precision. It is found that higher-order corrections are important for reproducing
lattice observables and have a significant impact on the phenomenology of strongly interacting pionic dark matter, particularly in the regime of big $M_\pi/F_\pi$.
Read the full abstract ▾
High Energy Physics (Experiment)
Neutral kaon mass measurement with the CMD-3 detector at VEPP-2000
E.P. Solodov, N.A. Petrov, R.R. Akhmetshin et al. (+52 more)
Using more than 600 thousand $K_{S}^{0}\to\pi^{+}\pi^{-}$ decays from the $e^{+}e^{-}\to\phi(1020)\to K_{S}^{0}K_{L}^{0}$ reaction, the neutral kaon mass has been measured with the CMD-3 detector at the VEPP-2000
collider. Using the beam energies control by the back-scattering
laser light
photons, and a calibration to the world average $\phi$-
meson mass, the neutral kaon mass is determind to be m($K^0$) = 497.587 $\pm$ 0.004(stat.) $\pm$ 0.008(syst.) $\pm$ 0.009(calibr.) \mevcc, where the first uncertainty is statistical, the second is systematic, and the third is the uncertainty from the energy calibration.
Read the full abstract ▾
All authors E.P. Solodov, N.A. Petrov, R.R. Akhmetshin, A.N. Amirkhanov, A.V. Anisenkov, V.M. Aulchenko, N.S. Bashtovoy, D.E. Berkaev, A.E. Bondar, A.V. Bragin, D.A. Epifanov, L.B. Epshteyn, A.L. Erofeev, G.V. Fedotovich, A.O. Gorkovenko, A.A. Grebenuk, S.S. Gribanov, D.N. Grigoriev, F.V. Ignatov, D.R. Ivanov, V.L. Ivanov, S.V. Karpov, V.F. Kazanin, I.A. Koop, A.A. Korobov, A.N. Kozyrev, P.P. Krokovny, A.S. Kuzmin, I.B. Logashenko, P.A. Lukin, K.Yu. Mikhailov, I.V. Obraztsov, A.V. Otboev, Yu.N. Pestov, E.A. Perevedentsev, A.S. Popov, Yu.A. Rogovsky, A.A. Ruban, N.M. Ryskulov, A.E. Ryzhenenkov, A.V. Semenov, A.I. Senchenko, Yu.M. Shatunov, V.E. Shebalin, D.N. Shemyakin, B.A. Shwartz, D.B. Shwartz, M.V. Timoshenko, V.M. Titov, A.A. Talyshev, S.S. Tolmachev, A.I. Vorobiov, I.M. Zemlyansky, D.S. Zhadan, Yu.V. Yudin
Earth and Planetary Astrophysics
The 3D Architecture of a pair of 6:1 Resonant Brown Dwarfs around the Naked-eye star $\nu$ Ophiuchi
Tianshenhong Sang, Guang-Yao Xiao, Ying-Yi Cao et al. (+8 more)
We present a revisiting study of the brown
dwarf pair orbiting the naked-eye ($V=3.3$) K-
giant $\nu$~Ophiuchi, located only 44\,pc from our
Solar system. By jointly analysing archival radial-velocity measurements together with astrometric data from Hipparcos and the
Gaia second and third data releases, we determine the three-dimensional architecture of the system and robustly constrain the masses of both companions. We find brown
dwarf masses of $m_{\mathrm{b}} = 24.2^{+6.4}_{-2.8}\,M_{\mathrm{J}}$ and $m_{\mathrm{c}} = 26.8^{+4.3}_{-2.9}\,M_{\mathrm{J}}$. The mathematical constraint, derived from the posterior distribution of the mutual inclination based on MCMC samples, yields a mutual inclination of $\psi_{\mathrm{bc}}=46^{+27}_{-24}\!\,^{\circ}$, while direct calculations based on the maximum a posteriori and posterior median orbital parameters yield values of $\sim$$10^{\circ}$ and $\sim$$20^{\circ}$, respectively. Resonance analysis indicates that the two companions can still be trapped in a 6:1 mean-motion resonance in the maximum a posteriori configuration. To place an upper limit for the mutual inclination, dynamical stability analysis over a 1~Myr timescale further constrains it to be no larger than $\sim$$15^{\circ}$. Systems hosting brown
dwarf pairs are rare, yet they provide important constraints on theories of planetary formation and dynamical
evolution. Current detections suggest that brown
dwarf pairs preferentially reside at large separations from their host
stars and are more common in less mature systems. This supports a
star-like formation pathway via gravitational instability in disk.
Read the full abstract ▾
All authors Tianshenhong Sang, Guang-Yao Xiao, Ying-Yi Cao, Huan-Yu Teng, Yu-Juan Liu, Wei Wang, Fan Liu, Fei Zhao, Meng Zhai, Fabo Feng, Shang-Fei Liu
Physics Education
Defining a physics person: Tensions in the identity development of undergraduate women in physics
Laura M. Akesson, Jessica L. Rosenberg, Nancy Holincheck et al. (+1 more)
This qualitative study explores how undergraduate women define what it means to be a physics person alongside how they describe their own physics identity. Our team analyzed 120 survey responses (97%, or 116 of the 120 respondents, identified as women or non-binary) to understand what factors are associated with an individual's physics identity. Those surveyed were attendees of Conferences for Undergraduate Women in Physics, who attended 88 unique institutions in 30 states. Our participants' conceptions of what it means to be a physics person fell into two themes: (1) people who are skilled academically and in research and (2) those who have an interest in physics ranging from an enjoyable interest to a life-devoting passion for the subject. When asked to explain their own physics identities, students responded through a personal and social lens more frequently than through an academic lens. Our analysis revealed three tensions in the development of undergraduate women's physics identity: (1) the tension between identifying entirely as a physics person and having other identities that are important to who they are, (2) the tension between the need for belonging in the physics community and their view of themselves as a physics person, and (3) the tension between their expectations of a physics person and their beliefs about their own abilities or interest.
Read the full abstract ▾
All authors Laura M. Akesson, Jessica L. Rosenberg, Nancy Holincheck, Benjamin W. Dreyfus
Fluid Dynamics · Cross-listed from cs.LG
A Validated LBM Dataset and Pipeline for Surrogate Modeling of Turbulent 3D Obstructed Channel Flows
Lukas Schröder, Shubham Kavane and Harald Köstler
Evaluating neural operators for 3D turbulent flow requires validated
datasets with physical
benchmarks. We present a reproducible pipeline generating training data for 3D channel flows around generated geometries at Re=1,000-10,000. Our
lattice Boltzmann solver with cumulant collision operators is rigorously verified against experimental measurements (Strouhal number, drag coefficients, turbulent fluctuations) with comprehensive grid convergence studies at resolution 1024x512x512. Building upon an established framework, this validated pipeline enables standardized surrogate model comparison. We outline planned systematic evaluation of
Fourier Neural Operator and U-Net variants on
forecasting, super-resolution, and error correction tasks, using physics-informed metrics to assess turbulent energy cascade representation. Future work will compare computational efficiency between numerical solvers and neural surrogates, exploring practical application. We seek community feedback on our validation approach, planned
benchmark methodology, and evaluation priorities for neural operators in turbulent flows.
Read the full abstract ▾
Quantum Physics
Charging Quantum Batteries with Chiral Squeezing
Borhan Ahmadi, André H. A. Malavazi, Janine Splettstoesser et al. (+2 more)
We propose a
quantum-battery charger based on a driven bosonic Kitaev chain (BKC), where
chiral squeezing converts passive input fluctuations into ordered, non-passive battery states. While a coherent input pulse exhibits phase-sensitive
chiral transport, the charging dynamics is dominated by bidirectionally propagating fluctuations that are amplified and squeezed into orthogonal quadratures at opposite chain ends. In contrast to conventional phase-preserving amplifiers, our scheme stores largely extractable energy and achieves a work-like signal-to-noise ratio (SNR) near unity, even in the presence of thermal noise and moderate
symmetry-preserving disorder.
Read the full abstract ▾
All authors Borhan Ahmadi, André H. A. Malavazi, Janine Splettstoesser, Paweł Horodecki, Lei Du
Accelerator Physics
Impedance of multilayer cylindrical structures with a material-filled beam region
Erik Kvikne, Elias Métral and Erik Adli
Beam-coupling impedances in material media are relevant for ionization-cooling channels of a future
muon collider, where the beam propagates in matter rather than
vacuum. We extend the cylindrical field-matching formalism for multilayer structures to the case of a material-filled beam region surrounded by external layers with arbitrary electromagnetic properties. Relative to the
vacuum formulation, the usual factor $1/\gamma^2$ is replaced by the material-dependent factor $F=1/\varepsilon_1-\mu_1\beta^2$, and the radial propagation constant is modified accordingly. Analytical expressions are obtained for the monopolar longitudinal and dipolar transverse impedances, with the surrounding structure encoded through reflection coefficients determined by field matching. The formalism reduces to the known
vacuum and perfectly conducting limits in the appropriate cases. Representative calculations are presented for absorber-relevant configurations, illustrating the dependence on the material properties of both the beam region and the surrounding layers. In particular, a finite beam-region conductivity can generate a real impedance component and reverse the sign of the imaginary space-charge impedance, while sufficiently high permittivity can give rise to resonant structures associated with oscillatory radial fields. The effect of finite-conductivity surroundings is also examined, showing the approach towards the perfectly conducting limit as the external conductivity is increased. The applicability of the infinite-length approximation is also discussed by comparison with finite-length mode-matching results.
Read the full abstract ▾