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Friday 31 July

Space Physics

Shrinking the Haystack: One-Class Machine Learning Detection of Magnetosheath Current Sheets in MMS Burst Data

Deep Ghuge, Daniel J. Gershman, Vadim Uritsky et al. (+1 more)

We present a morphology-first framework for narrowing the search for magnetic-reconnection candidates in Magnetospheric Multiscale (MMS) burst-mode data. The target is the small, short, and frequently electron-only reconnecting current sheets that occur in turbulent magnetosheath plasma. The pipeline operates in two stages. A local frame-quality gate based on minimum-variance analysis first retains only windows whose current-sheet coordinates are well defined. A one-class Deep Support Vector Data Description neural network then scores those windows against a library of 3,000 physically calibrated synthetic current sheets generated by Monte Carlo from a single published reference event. Acceptance into the surrogate library is governed by the second-order structure function $S_2(\tau)$: a candidate is admitted only if its multi-scale fingerprint tracks that of the seed event inside a tolerance band, together with a small number of shape-based checks. This $S_2(\tau)$-anchored construction defines the in-class distribution directly from a well-understood reference event and sidesteps the absence of a curated negative class in turbulent magnetosheath data. Applied to 15 magnetosheath turbulence intervals from the literature (1.58 h of burst-mode coverage), the framework compresses 22,775 sliding windows to 270 candidate detections (a 98.8% reduction). Manual visual screening identifies 93 of these as candidate reconnection events and a further 118 as sheet-like, retaining 78% of the queue for follow-up; the candidate-reconnection pool extends well beyond the 22 detections that overlap the published reconnection-event catalog used here as a sanity check. The framework is intended as the data-reduction stage of a broader reconnection-search workflow, offered here as an initial proof of concept before extending the one-class design to additional feature channels.
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All authors Deep Ghuge, Daniel J. Gershman, Vadim Uritsky, Julia E. Stawarz

Lattice Field Theory

Parton distribution functions from lattice QCD

Martha Constantinou and Krzysztof Cichy

Parton distribution functions (PDFs) provide one of the most direct ways to describe the partonic structure of hadrons in QCD. They encode nonperturbative information about quarks, antiquarks, and gluons as functions of the partonic momentum fraction $x$, and they connect this microscopic structure to experimentally measurable high-energy scattering processes through QCD factorization. This makes PDFs interesting to pursue with lattice QCD, which provides a first-principles formulation of the strong interaction. The challenge is that PDFs are defined through light-cone correlations, while lattice QCD is formulated in Euclidean spacetime. This chapter introduces the theoretical foundations and current status of lattice-QCD calculations of PDFs, with emphasis on modern approaches based on spatially nonlocal matrix elements. We first review the light-cone definitions of quark and gluon PDFs, their Mellin moments, and the connection to QCD factorization. We then explain how large-momentum effective theory, short-distance factorization, and the short-distance operator product expansion make it possible to relate Euclidean lattice observables to light-cone partonic structure. Particular attention is given to the elements that have improved over the last five years: renormalization of Wilson-line operators, perturbative matching, finite-momentum and finite-distance effects, reconstruction of the $x$ dependence, and systematic uncertainties. We summarize selected lattice results for proton quark PDFs, pion and kaon PDFs, gluon PDFs, and twist-3 distributions, highlighting both recent progress and remaining challenges. As will be demonstrated, lattice QCD is moving from proof-of-principle calculations toward systematically improvable determinations that can complement experimental data and global QCD analyses in mapping the partonic structure of hadrons.
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Instrumentation and Methods for Astrophysics

Directional Anisotropic Sensitivity Curves for Pulsar Timing Arrays

Daniel J. Oliver, Jeffrey S. Hazboun, Martine Maggi et al. (+2 more)

After two decades of observations, pulsar timing array collaborations have reported strong evidence for a stochastic gravitational wave background, most likely sourced by an inspiraling population of supermassive black hole binaries. Because that population is finite, anisotropy in the background is inevitable, producing hotspots on the sky that track the loudest binaries. Building on the Fisher formalism for anisotropic backgrounds, we recast the directional Fisher information as effective sensitivity curves on the sky, distinguishing the radiometer and full-Fisher estimators, along with a sky-weighted curve that reduces the anisotropic sky to a single spectrum and recovers the standard isotropic curve in the isotropic limit. We implement five sky-decomposition bases: pixel, spherical harmonic, square-root spherical harmonic, radiometer, and principal-map. We demonstrate the framework on an IPTA-like pulsar timing array: characterizing the angular response, analyzing the Fisher structure, recovering injected anisotropic hotspots, and forecasting future-array sensitivity. The framework is released as an extension to the sensitivity software package hasasia.
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All authors Daniel J. Oliver, Jeffrey S. Hazboun, Martine Maggi, Jeremy G. Baier, Kyle E. Gourlie

Adaptation and Self-Organizing Systems · Cross-listed from eess.SY

Dynamical principles of habituation across substrates and scales

Matthew Smart, Stanislav Y. Shvartsman and Martin Mönnigmann

Habituation is a basic form of learning in which a system's response to repeated stimulation progressively diminishes but eventually recovers when the stimulus is withheld. Long studied in animals, it has increasingly been observed in unicellular organisms and non-living devices such as electronic circuits and neuromorphic materials, suggesting underlying dynamical principles that recur across domains. This review asks what those principles are: given qualitative constraints imposed by habituation on a system's response, what is the minimal dynamical structure that satisfies them? We formalize the classical hallmarks of habituation as behavioral constraints on input–output behavior, show that linear time-invariant systems are structurally incompatible with these constraints, and construct nonlinear motifs—linear fading-memory dynamics composed with static nonlinearities—that exhibit the hallmarks across diverse settings. We relate these motifs to models of specific biological systems and to physical and algorithmic realizations, from analog circuits to transient computation in machine learning.
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Astrophysics of Galaxies

Stellar mergers and chemical element mixing: implications for the metamorphic stellar evolution in AGN disks

Yanlong Shi, Xiaoshan Huang, Douglas N. C. Lin et al. (+1 more)

Chemical mixing during stellar mergers can significantly influence the subsequent evolution of the merger remnant. We perform a suite of three-dimensional hydrodynamical simulations of stellar mergers, each evolved for $\sim100$ stellar dynamical times until the remnant reaches a quasi-hydrostatic equilibrium. The simulations incorporate subgrid-scale diffusion models to capture the turbulent mixing of chemical elements. Starting with an idealized polytropic equation of state (EOS), we first identify the dominant mixing mechanisms and investigate how the merger outcome depends on the mass ratio, relative velocity, impact parameter, and stellar structure. We then extend our simulations to the context of stars embedded in active galactic nucleus (AGN) disks, using a realistic, composition-dependent EOS and AGN stellar models generated with the stellar evolution code MESA. We find that mergers with both younger metamorphic stars and H-rich accreting AGN stars can substantially rejuvenate old metamorphic stars through efficient core mixing after thermal relaxation. The merger remnants are nitrogen-enriched, with ${\rm N/O}\sim1$–3 and ${\rm N/C}\gtrsim5$, comparable to the abundances observed in the nebula surrounding SN 1987A. During subsequent stellar evolution, the remnants may converge onto the main sequence of isolated metamorphic AGN stars once they reach accretion–wind equilibrium. They may also deposit a significant amount of chemically enriched material into the AGN disk. This work provides a physical framework for connecting hydrodynamical stellar mergers with the long-term evolution of AGN stars and their observational and chemical signatures.
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All authors Yanlong Shi, Xiaoshan Huang, Douglas N. C. Lin, Norman Murray

Atmospheric and Oceanic Physics

From Flight Logs to Atmospheric Science: Paragliders as Convection Sensors for Identifying Thermal Predictors

César Hernández-Aguayo, Matthieu Cristelli and Michael Benzaquen

Atmospheric thermal convection drives boundary-layer dynamics and vertical exchange of heat, moisture, and momentum, yet fundamental questions about thermal structure remain open due to limited in situ observational coverage. We introduce a novel high-resolution observational dataset for atmospheric convection based on paragliding flight logs collected over metropolitan France during 2017-2024. Paragliders probe thermal updrafts by circling within them while carrying GPS variometers that record position and altitude; each climbing segment samples the vertical velocity field within a thermal column. Aggregated across 1.47 million climbing segments from 110,730 flights, this dataset provides unprecedented spatial coverage and temporal resolution. To demonstrate the value of this observational resource, we extract three physically distinct observables from climbing segments and characterize their dependence on terrain, season, time of day, cloud state, and soil moisture. Coupling the paragliding observations with global atmospheric reanalysis data (ERA5, 0.25 degrees hourly) through a regression framework against 118 physically interpretable predictors, we identify leading atmospheric predictors of these observables. The empirical relationship between ceiling height and temperature-dew point depression matches the theoretical lifting condensation level scaling with striking precision supporting our methodology. Boundary-layer height emerges as the leading independent predictor of both ceiling height and thermal strength across all terrains and seasons, while vertical-velocity variability is controlled by surface heat-flux and wind variables. Taken together, our results highlight the utility of crowdsourced flight-log data for investigating atmospheric convection.
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General Relativity and Quantum Cosmology

Optical Landscapes and High-Energy Collisions in Hairy Horndeski Gravity

Filipe Cattete Alves and Rodrigo Maier

We investigate the null geodesic structure, photon sphere dynamics, and high-energy particle collisions within a class of static, spherically symmetric hairy Horndeski black holes. Characterized by an invariant metric root at $r = 2M$ and a scalar hair parameter $Q$, the spacetime maps onto four distinct geometric domains dictated by the surface gravity $\kappa|_{2M}$. We derive exact analytical expressions for the photon sphere radius $r_{\text{ph}}$ and its dynamic stability criterion, showing that external circular null orbits remain dynamically unstable across non-extremal regimes. Crucially, we prove that a stable photon sphere arises exclusively in the extremal configuration ($Q = -2M$), where it coincides precisely with the degenerate horizon ($r = 2M$). We argue that this horizon-bound stable photon orbit acts as an infinitely redshifted bound state for light and ultra-relativistic particles. Finally, we analyze the Bañados-Silk-West (BSW) effect for infalling timelike test particles, demonstrating that the center-of-mass energy $E_{\text{cm}}$ for critical collisions diverges as $E_{\text{cm}} \propto (r - r_h)^{-1/2}$ strictly at the extremal threshold $Q = -2M$.
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Fluid Dynamics · Cross-listed from math.AP

Delayed Dissipation for Two-Dimensional Vortex Sheets

Victor Armegioiu

We quantify viscous energy loss for two-dimensional Delort vortex sheets. Let $u^\nu$ be Leray-Hopf solutions on $\mathbb{T}^2$ with uniformly bounded kinetic energy and total vorticity variation, and write $\omega_0^\nu=\mu_0^\nu+f_0^\nu$, where $\mu_0^\nu\geq0$ and $f_0^\nu$ is bounded in $L^p$, $p>1$. For every fixed $0<\delta<T$, $\nu\int_\delta^T\|\omega^\nu(t)\|_2^2\,\mathrm{d}t\lesssim_{\delta,T}\frac{1}{|\log\nu|}$. This improves the $O(|\log\nu|^{-1/2})$ bound of De Rosa and Marcotullio under the same assumptions and thereby disproves their Conjecture 1.6 (arXiv:2602.15670, v1). The proof uses a sharp $L^2$-$H^1$-$H^{-1}$ interpolation inequality for nonnegative densities, retaining the total interaction energy of the positive vorticity rather than only its largest local mass. The bound also remains effective when the observation time grows with the Reynolds number. If the initial velocities are relatively compact in $L^2$, the loss still vanishes whenever $\log T_\nu=o(|\log\nu|)$; in particular, any prescribed energy loss must wait at least until $\nu^{-a}$ for some $a>0$. Previous estimates covered only $T_\nu=o(\exp(|\log\nu|^\kappa))$, $\kappa<1/2$, so this gives a polynomial lower bound on the energetic lifetime of the inviscid vortex-sheet model. If instead $f_0^\nu$ is bounded in $L(\log L)^\alpha$, the rate is $O(|\log\nu|^{-q_\alpha})$, $q_\alpha=\min\{2\alpha,1\}$, and the loss vanishes when $\log T_\nu=o(|\log\nu|^{q_\alpha})$. On $\mathbb{R}^2$, exact radial solutions attain these exponents for $0<\alpha\leq1/2$. At the endpoint, a bounded-energy $L^p$ family attains the rate $1/|\log\nu|$, while every fixed radial datum dissipates $o(1/|\log\nu|)$ and can lose a fixed amount of energy only on the diffusive scale $1/\nu$.
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Optics

Controlled generation of high-harmonic spatiotemporal optical vortices

Titouan Gadeyne, Vartika Vishnoi and Thierry Ruchon

Spatiotemporal optical vortex (STOV) pulses are puzzling states of light, which see their transverse orbital angular momentum being debated in spite of possessing a topological charge. Thus far studied at conventional optical wavelengths, we herein demonstrate their upconversion to extreme ultraviolet (XUV) frequencies via high-harmonic generation (HHG). Circularly-symmetric infrared STOV pulses of topological charges $\ell=\pm1$ and $\pm2$ from a bespoke pulse shaper are focused in argon to drive harmonics, each order $q$ forming a spatiospectral ring in the far-field. Dependence of their radii on $q$ and $\ell$ indicates XUV vortices of charge ${\ell}_{q} = q \times \ell$, and sensitivity of these modes to the focus position further establishes control over their production. The availability of XUV STOVs unlocks investigations and applications of their elusive angular momentum in the context of photoionization and other ultrafast spectroscopies.
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Superconductivity

Analytical Charge Density Profile of Vortex Core in Weak-Coupling Superconductor

Chi-Ken Lu

Self-consistent Bogoliubov-de Gennes calculations have long shown that solving the Poisson equation inside a superconducting vortex turns a one-signed charge depletion into a modulation that alternates in sign with period $\pi/k_F$. We give an elementary account of that result. Taking the Caroli-de Gennes-Matricon bound states in a step-like gap, we show that the normalization of the bound-state spinor is nearly independent of angular momentum, which collapses the mode sum into closed form. Inside the core the vortex winding removes one Bessel channel from a completeness sum, so the density vanishes on the vortex line and carries Friedel-like oscillations of wavevector $2k_F$; outside it the sum gives a $1/r$ envelope decaying over a coherence length, with a residual ripple. The bound-state charge does not integrate to zero, so neutrality obliges the extended states to compensate it exactly. That compensation is complete at long wavelength but fails at the diameter of the Fermi circle, and what survives is a sign-alternating $2k_F$ modulation reduced only by $4k_F^2/(4k_F^2+k_{TF}^2)$, a factor lying between one-half and three-quarters for any metal. The oscillation is therefore not a delicate effect but a consequence of neutrality and the inefficiency of screening at large momentum transfer: in the screened total the smooth terms cancel and only the ripple is left.
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Quantum Physics

Dissipation in Periodically Driven Quantum Systems: Partial Secularization and Thermodynamic Consistency

Luísa T. Tude, Carlos Ortega-Taberner, Roberta Zambrini et al. (+1 more)

Periodically driven open quantum systems are central to quantum thermodynamics and quantum control. These systems are typically described using Floquet-Born-Markov master equations, derived with the use of a full secular approximation, and whose thermodynamic implications are often overlooked. In this context, we show that such a strong secular approximation may lead to unphysical predictions for steady state energy currents. We then demonstrate that a coarse-grained formulation of the master equation can regularize these issues while yielding completely positive dynamics and consistent energy currents. The coarse-graining time has a clear physical interpretation, as it defines the temporal resolution at which a Markovian master equation can describe the evolution of the periodically driven system. We show the consistency and validity of our approach by comparing to an exact non-Markovian simulation in paradigmatic examples: a driven two-level system and a three-level maser coupled to hot and cold thermal reservoirs. Our work provides a practical framework for correctly applying the secular approximation in periodically driven-dissipative systems and for assessing the accuracy of master equations of the GKSL form.
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All authors Luísa T. Tude, Carlos Ortega-Taberner, Roberta Zambrini, Gonzalo Manzano

Quantum Physics

Marked vertex search on disordered graphs with Rosenzweig-Porter phases

Sabyasachi Chakraborty, Tilen Cadez, Sonjoy Majumder et al. (+1 more)

Quantum marked vertex search algorithms are known to outperform their classical counterparts, yet their behavior in the presence of disorder remains largely unexplored. Here, we address this gap by studying marked vertex search on disordered random graphs. To introduce disorder, we implement the Rosenzweig-Porter (RP) model, a random matrix ensemble with tunable ergodic, non-ergodic extended, and localized phases, on Erdős-Rényi (ER) graphs. This produces a doubly random system where ER graph connectivity randomizes which interactions exist, while RP disorder controls their strength and `on-site' potentials, providing a two-parameter framework to study quantum dynamics on disordered networks. First, we show that the characteristic Wigner-Dyson-to-Poisson spectral crossover of the RP ensemble survives under graph constraints across the sparse-to-dense range, and we derive an analytical estimate for the finite-size localization boundary that shifts systematically with the graph edge probability $p$, consistent with a resonant-hybridization argument. Thereafter, using this disordered graph ensemble, we study the marked vertex search problem and find that search performance tracks the underlying quantum phase directly. Counterintuitively, the ergodic phase, despite supporting fast transport, yields lower success probability than the localized phase, which achieves high success probability at the cost of significantly longer search times. These results establish a direct and quantitative link between random matrix disorder on graphs and the performance of continuous-time quantum walk search, and suggest that disorder, rather than being merely an obstacle, can be exploited as a tunable parameter in quantum search protocols.
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All authors Sabyasachi Chakraborty, Tilen Cadez, Sonjoy Majumder, Rohit Kishan Ray

Instrumentation and Methods for Astrophysics

Calibration of MEMS DM actuator gains using a Zernike wavefront sensor on the HiCAT testbed and implications for Habitable Worlds Observatory operations

Sarah Steiger, Raphaël Pourcelot, Rémi Soummer et al. (+4 more)

Deformable mirrors (DMs) are a key component of coronagraph instruments performing adaptive optics on the ground, and for future space observatories such as HWO and Roman CGI. Here, they will be used as part of the wavefront sensing and control system to "dig a dark zone” - remove residual stellar light to create a high-contrast region in the focal plane where faint companions can be detected. To reach the deep contrasts needed to directly image cool or reflected light planets (<1e-8) accurate calibration of the DM actuator gain is essential as picometer differences between the expected and realized DM surface can significantly degrade dark zone (DZ) digging efficiency. This increases the overheads needed to achieve a DZ and critically places more stringent requirements on observatory stability. Furthermore, DM gain varies with actuator stroke, necessitating rapid, in situ gain map recalculations to maintain DZ digging efficiency over time. Zernike wavefront sensors (ZWFS) are well-suited for this task as they efficiently provide picometer-level sensitivity and will likely already be included on board as part of a low order wavefront sensor for HWO. Here we present results from the HiCAT testbed at STScI where we calibrated gain maps for our Boston Micromachines 952-actuator micro electromechanical (MEMS) DMs using both a Fizeau interferometer and a ZWFS to compare performance. With the ZWFS we compute a gain map using both local linear fits around a given DM solution, and present a formalism for deriving more complex quadratic solutions which are more computationally intensive, but accurate over most of the dynamic range of each actuator. We then use these techniques to calibrate the DMs on the HiCAT testbed and show increased DZ digging efficiency with the new gain map and better contrast performance moving from 14 to 16 bit control electronics as enabled by these calibrations.
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All authors Sarah Steiger, Raphaël Pourcelot, Rémi Soummer, Emiel H. Por, Laurent Pueyo, Iva Laginja, Nathan Scott

High Energy Physics (Phenomenology)

Large-Field Vacuum Decay in General Multi-Scalar Theories

Giorgio Busoni, Florian Goertz, Navneet Krishnan et al. (+1 more)

Many theories beyond the standard model exhibit multiple scalar particles. Such multi-scalar theories can in principle host lower-energy vacua, and thus predict that our universe has a finite lifetime due to false vacuum decay. This scenario cannot be ruled out a priori as even the standard model's electroweak vacuum has been shown to be metastable; however, for theoretical consistency, we still require that the model does not predict a lifetime much smaller than the age of the universe. The calculation of these tunneling rates at leading order for multi-scalar theories typically includes numerical approaches, or approximations which are frequently not analytically controlled. In this article we show that, in the large-field regime, a one-dimensional radial bounce always produces the exact dominant contribution to the leading order tunneling rate, with corrections being exponentially suppressed. This allows us to write simple analytical expressions to calculate the tunneling rate in multi-scalar theories, in terms of an effective quartic coupling $\lambda_\text{eff}$. For theories with biquadratic scalar potentials, we also derive straightforward analytical expressions for $\lambda_\text{eff}$ in terms of the original theory's couplings. Finally, we provide example applications of our results to study the vacuum stability of the 2HDM+a model and the 3-3-1 model.
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All authors Giorgio Busoni, Florian Goertz, Navneet Krishnan, Rickson Wielian

Computational Physics · Cross-listed from cs.LG

A Physics-Chemistry-Informed Neural Network (PCINN) for Real-Time Spatial-ALD Coverage Prediction and Reliable Kinetics Inversion

Ning Hu, Chang Liu, Yunlei Jiang et al. (+1 more)

Spatial atomic layer deposition (SALD) is a leading atmospheric-pressure, high-throughput route to industrial ALD, but design and control are limited by the cost of predicting surface coverage: high-fidelity CFD is far too slow for operating-window scans, while analytic models miss transport modulation such as the gas curtain. We present a physics-chemistry-informed neural network (PCINN), a hybrid surrogate with CFD-level accuracy at real-time speed: a query returns coverage in about 7 ms, roughly 5x10^4 times faster than a CFD solve, reaching a test R^2_log = 0.998 (leave-one-out R^2_raw = 0.974) from only 30 training cases spanning four orders of magnitude in coverage. The architecture is not a black box: a small network learns only the operating-condition to near-wall concentration closure, while the known surface kinetics is a hard-coded, trainable chemistry layer integrated along the substrate trajectory. This single-scalar bottleneck keeps it accurate under sparse data, interpretable and invertible. We add a full identifiability analysis (Fisher information, profile likelihood). The adsorption energy E_ads and desorption rate k_des are robustly identifiable; k_ads is not separately identifiable at a single temperature (only k_ads*c_wall is). Across four temperatures the prefactor nu and E_ads bind along a weakly identifiable degeneracy valley of slope 0.065 eV/decade, derived analytically as k_B T_eff ln(10) and turned into a reliability diagnostic: a seven-chemistry mismatch matrix shows it is invariant under any single-Arrhenius mismatch and shifts only when a second thermally activated process appears, so a slope departure flags unmodelled site heterogeneity. Data come from simulation with known ground truth inverted by the same kinetic form, so the study verifies pipeline self-consistency and the identifiability boundary, not real parameters.
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All authors Ning Hu, Chang Liu, Yunlei Jiang, Yuan Dong

Mesoscale and Nanoscale Physics

Ion Flow under an Applied Electric Field in Semiconducting and Metallic Carbon Nanotubes

J. B. Sokoloff

Measurements made by Li, et. al., showed that the flow rates of potassium ions through 11nm long, subnanometer diameter, metallic and semiconducting carbon nanotubes under an applied electric field are almost the same. In contrast, measurements of the electrical conductivity of potassium chloride solution through 100 long metallic and semiconducting carbon nanotubes with diameters between 2.6-5.4nm by Cui, et. al., show that the ionic conductivity in the semiconducting nanotubes is larger than that of the metallic nanotubes. Possible theoretical origins of these differences are explored in this article.
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Strongly Correlated Electrons

Chiral Magnon Mixing by Symmetry-Breaking in Collinear Ferrimagnets

Dhurba R. Jaishi, Tyler J. Slade, S. X. M. Riberolles et al. (+8 more)

Magnons in ferromagnets possess spin angular momentum defined by right-handed precession of the moment around the magnetization direction. In antiferromagnets with no net magnetization, left-and right-handed magnons are degenerate in the absence of an applied field. Ferrimagnets possess uncompensated magnetic sublattices, which should natively possess right-and left-handed magnons where their energy is split by the internal molecular field. Here, we show that RMn6Sn6 (R = Tb, Er) ferrimagnets possess right and left-handed magnon bands that cross at finite momentum (k) within the basal plane, defining modes with opposite dynamical chirality. Depending on the symmetry of the ferrimagnetic order, which may be manipulated by varying the rare-earth magnetic anisotropy or with applied field, the band crossing may remain a nodal line or may be gapped. The gapped modes contain hybridized chiral excitations whose chirality becomes k-dependent.
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All authors Dhurba R. Jaishi, Tyler J. Slade, S. X. M. Riberolles, Bing Li, Tianxiong Han, D. M. Pajerowski, D. L. Abernathy, Barry Winn, Melissa Graves-Brook, B. G. Ueland, R. J. McQueeney

High Energy Physics (Theory)

Infrared Problem in Quantum Electrodynamics

Igor Frolov and Albert Schwarz

It is well known that the inclusive cross section in QED is infrared finite. In the standard diagram techniques this result follows from cancellation of infrared divergences. We suggest a new approach that should lead to IR -safe computational technique for QED with massive fermions.
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Fluid Dynamics

Multiscale passive scalar turbulence in a compressed subspace via tensor trains

Stefano Pisoni, Egor Tiunov and Chiara Calascibetta

Capturing the multiscale statistics of turbulence in compressed form remains a central challenge for reduced-order modeling. We introduce a hybrid Tensor Train (TT) approach for a highly intermittent passive scalar. The hybrid TT matches Galerkin, wavelet, and standard TT decompositions for the structure functions while improving the representation of intermittent, non-Gaussian fluctuations. These results open a route toward evolving the linear dynamics of passive scalars directly in compressed tensor form, with potential applications to quantum algorithms for fluid transport.
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Instrumentation and Methods for Astrophysics

WST instrument Exposure Time Calculator: full simulation of multi-mode spectrograph performance from source to detector

Matteo Ferro, Matteo Genoni, Henri M. J. Boffin et al. (+13 more)

We present a comprehensive Exposure Time Calculator (ETC) developed for the Wide-field Spectroscopic Telescope (WST) concept. The WST, currently in its conceptual phase, is designed as a next-generation large spectroscopic survey facility featuring three complementary observing modes: an Integral Field Spectrograph (IFS) covering 370-930 nm at R of about 4800; a high-resolution Multi-Object Spectrograph (MOS-HR) with four bands at R of about 40000; and a low-resolution Multi-Object Spectrograph (MOS-LR) with four channels at R of about 3800-4900. The ETC simulates the complete photon-propagation path from astronomical source to detector, incorporating wavelength-dependent system throughput (telescope transmission, instrumental optics, detector quantum efficiency), accurate sky background via ESO SkyCalc integration, and a comprehensive noise treatment (photon noise, sky background, read-out noise, dark current). The computational core is implemented as the "pyetc_wst" Python library built on the MPDAF framework, supporting multiple target spectral energy distributions (stellar templates, blackbody, power-law, emission lines, and user-uploaded spectra with arbitrary redshift) and spatial morphologies (point sources and Sersic extended profiles). Four operational modes enable flexible exposure-time optimization. Full spectral outputs include wavelength-dependent signal-to-noise ratio (SNR), source and sky photon counts, noise decomposition by component, and simulated extracted spectra. An interactive web interface, together with a REST API and a command-line tool, complete the user experience and enable batch survey-design workflows.
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All authors Matteo Ferro, Matteo Genoni, Henri M. J. Boffin, Jose Schiappacasse-Ulloa, Sofia Randich, Roland Bacon, Vincenzo Mainieri, Alessio Mucciarelli, Carmela Lardo, Michele Moresco, Cristian Vignali, Margherita Talia, Andrea Scaudo, Marco Landoni, Roelof S. de Jong, Olga Bellido-Tirado

Instrumentation and Methods for Astrophysics

An upgraded frequency-selectable laser source (FLS) calibrator for CMB bandpass characterization

Lauren J. Saunders, Sara M. Simon, Shreya Sutariya et al. (+4 more)

One of the biggest challenges for Cosmic Microwave Background (CMB) experiments comes from the uncertainty in instrument bandpass calibration. Uncertainties in bandpass can limit foreground removal and spectral fitting, which are critical for inflationary and galaxy cluster measurements. CMB experiments currently use Fourier Transform Spectrometers (FTSes) to measure instrument bandpasses. However, FTS systems are currently systematics-limited, so significant improvements in bandpass measurements require novel calibrators. To this end, we developed a Frequency-selectable Laser Source (FLS) calibrator, which uses a laser with adjustable frequency coupled to a system that allows for laser power attenuation. Following initial testing with the first FLS prototype, we developed an upgraded version of the calibrator with improved performance. We present the upgrades to the FLS calibrator, the characterization of the upgraded calibrator and new laser source, and plans for testing with microwave instruments in the field.
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All authors Lauren J. Saunders, Sara M. Simon, Shreya Sutariya, Elisa Russier, Sanah Bhimani, Erin Healy, Jeffrey McMahon

Nuclear Experiment

Hadron Spectroscopy: Experimental Overview

Volker Crede

One of the most fascinating phenomena in nuclear and particle physics is the formation of light hadrons – strongly interacting particles – out of massless gluons and almost massless quarks. These particles exhibit rich excitation spectra due to their complex quark-gluon structures. Short-lived pairs of virtual quarks and antiquarks are continually formed and annihilated inside hadrons. Every physics student probably knows that the proton consists of three quarks. This statement is misleading, though. For example, the proton only shows a constant excess of three quarks versus antiquarks from the outside, and these three quarks are not even well defined. Understanding hadrons goes well beyond explaining their properties in terms of three quarks for baryons and a quark-antiquark pair for mesons. Much like atomic spectroscopy revealed the structure of atoms through discrete energy levels, hadron spectroscopy seeks the mapping of the spectrum of hadronic states and to use that information to better understand the underlying theory of the strong force – Quantum Chromodynamics (QCD). Over the past few decades, hadron spectroscopy has entered an exciting new era with the discovery of many exotic hadrons that do not fit neatly into the traditional quark model classification of ordinary baryons and mesons. Many of the discoveries come from the heavy-flavor sector. As experimental techniques and computational methods continue to advance, hadron spectroscopy will remain a vital tool for probing the deepest layers of matter and understanding the fundamental structure of the universe.
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Nuclear Experiment

Collision energy and system size dependence of $p_{\mathrm{T}}$-differential radial flow fluctuations $v_{0}(p_{\mathrm{T}})$ at RHIC

Zaining Wang

We report the first RHIC measurements of $v_{0}(p_\mathrm{T})$ in Au+Au collisions at $\sqrt{s_\mathrm{NN}}=7.7$–$200$ GeV and O+O collisions at $\sqrt{s_\mathrm{NN}}=200$ GeV. The integral fluctuation $v_0$ follows a common $N_{\rm ch}$ dependence in large and small systems, suggesting that the fluctuation magnitude is predominantly controlled by event-by-event fluctuations of the initial transverse size. The normalized response $v_0(p_\mathrm{T})/v_0$ factorizes across centralities and systems, revealing a universal hydrodynamic response $\kappa_0(p_\mathrm{T})/\kappa_0$ largely independent of the fluctuation amplitude. Identified-hadron mass ordering and viscous model comparisons demonstrate sensitivity to bulk viscosity ($\zeta/s$). These results establish $v_0(p_\mathrm{T})$ as a probe of the radial hydrodynamic response, collectivity across large and small collision systems, and QGP transport properties.
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Quantum Physics

Phase transitions in quantum-circuit compilation

Andrea De Girolamo, Davide Rattacaso, Simone Notarnicola et al. (+2 more)

Quantum-circuit compilation aims at finding an optimized realization of a target circuit under given constraints, e.g., the minimization of hardware-induced errors and the unitary-equivalence of the circuit. We connect the compilation process with the thermodynamics of a many-body spin system: circuit infidelity plays the role of the energy function and low-temperature states correspond to compiled circuits. In the paradigmatic case where crosstalk between parallel gates is present, we find a phase transition between a disordered phase and an antiferromagnetic brick-wall phase, compatible with the Ising universality class. At larger crosstalk, we observe a $\mathbb{Z}_3$-ordered regime, suggesting that increasingly serial compiled circuits are associated with emergent $\mathbb{Z}_n$-ordered phases. When the unitary-equivalence constraint is removed, these phases disappear, showing that the equivalence between circuits underlies the emergent criticality and constitutes a source of complexity in quantum-circuit compilation and, more generally, in equivalence-constrained optimization. Finally, we observe that the Kolmogorov complexity of the circuit enhances the emergence of ordered phases.
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All authors Andrea De Girolamo, Davide Rattacaso, Simone Notarnicola, Ilaria Siloi, Simone Montangero

High Energy Physics (Theory)

Minimal Massive Gravity Coupled to Higher Spins

Franz Ciceri, Nihat Sadik Deger, Bastien Duboeuf et al. (+1 more)

Among three-dimensional massive gravities, Minimal Massive Gravity (MMG) is distinguished by a parameter regime in which the AdS bulk theory and the dual conformal field theory can be simultaneously unitary. We couple MMG to a finite tower of higher-spins by promoting the fields of its first-order formulation to $\mathfrak{sl}(N)$-valued ones. We also present an extended formulation involving a group-valued Stückelberg scalar, which realizes the higher-spin translations broken by the massive deformation. We then construct AdS$_2\times$S$^1$ solutions carrying higher-spin hair specific to the massive theory. Finally, we analyse the mass spectrum of the higher-spin modes around AdS$_3$.
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All authors Franz Ciceri, Nihat Sadik Deger, Bastien Duboeuf, Henning Samtleben

Nuclear Experiment

Modification of $\Upsilon$ production in $p$O and OO collisions at LHCb

LHCb collaboration: R. Aaij, M. Abdelfatah, A.S.W. Abdelmotteleb et al. (+1187 more)

The production rates of $\mathit{\Upsilon}(2S)$ and $\mathit{\Upsilon}(3S)$ mesons relative to that of the $\mathit{\Upsilon}(1S)$ state are measured in $pp$, $p$O, and OO collisions by the LHCb collaboration. The ratios measured in $pp$ data are consistent with previous LHCb measurements at different center-of-mass energies. Only slight relative suppression of the $\mathit{\Upsilon}(2S)$ and $\mathit{\Upsilon}(3S)$ states is found in $p$O collisions, while in OO collisions the $\mathit{\Upsilon}(2S)$ is suppressed by a factor of $\sim2$, with evidence for suppression of the $\mathit{\Upsilon}(3S)$. The significant suppression in OO data, compared to the small effect in $p$O data, shows the emergence of additional suppression mechanisms in the relatively small OO collision system. Models incorporating quark-gluon plasma formation in OO collisions successfully describe the data. Implications for the interplay between cold nuclear matter effects and color screening in a deconfined quark-gluon plasma are discussed.
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All authors LHCb collaboration: R. Aaij, M. Abdelfatah, A.S.W. Abdelmotteleb, C. Abellan Beteta, F. Abudinén, T. Ackernley, A.A. Adefisoye, B. Adeva, M. Adinolfi, P. Adlarson, C. Agapopoulou, C.A. Aidala, S. Akar, K. Akiba, H. Al Saleh, P. Albicocco, J. Albrecht, R. Aleksiejunas, F. Alessio, P. Alvarez Cartelle, S. Amato, J.L. Amey, Y. Amhis, Z. Amos, L. An, L. Anderlini, P. Andreola, M. Andreotti, S. Andres Estrada, A. Anelli, D. Ao, C. Arata, F. Archilli, Z. Areg, M. Argenton, S. Arguedas Cuendis, L. Arnone, M. Artuso, E. Aslanides, R. Ataíde Da Silva, M. Atzeni, B. Audurier, J.A. Authier, D. Bacher, I. Bachiller Perea, S. Bachmann, M. Bachmayer, J.J. Back, M. Bai, Z.B. Bai, V. Balagura, A. Balboni, W. Baldini, Z. Baldwin, L. Balzani, H. Bao, J. Baptista de Souza Leite, C. Barbero Pretel, M. Barbetti, I.R. Barbosa, W. Barker, R.J. Barlow, M. Barnyakov, S. Baron, S. Barsuk, W. Barter, J. Bartz, S. Bashir, B. Batsukh, P.B. Battista, A. Bavarchee, A. Bay, A. Beck, M. Becker, F. Bedeschi, I.B. Bediaga, N.A. Behling, S. Belin, A. Bellavista, I. Belyaev, G. Bencivenni, E. Ben-Haim, J.L.M. Berkey, R. Bernet, A. Bertolin, L. Bertsch, F. Betti, J. Bex, O. Bezshyyko, S. Bhattacharya, M.S. Bieker, N.V. Biesuz, A. Biolchini, M. Birch, F.C.R. Bishop, A. Bitadze, A. Bizzeti, T. Blake, F. Blanc, J.E. Blank, S. Blusk, J.A. Boelhauve, O. Boente Garcia, T. Boettcher, A. Bohare, C. Bolognani, R.B. Bonacci, A. Bordelius, F. Borgato, S. Borghi, M. Borsato, J.T. Borsuk, E. Bottalico, S.A. Bouchiba, M. Bovill, T.J.V. Bowcock, A. Boyer, C. Bozzi, J.D. Brandenburg, A. Brea Rodriguez, N. Breer, C. Breitfeld, J. Brodzicka, J. Brown, E. Buchanan, M. Burgos Marcos, C. Burr, E. Butera, C. Buti, J.S. Butter, J. Buytaert, W. Byczynski, S. Cadeddu, H. Cai, Y. Cai, Y. Cai, A. Caillet, R. Calabrese, L. Calefice, M. Calvi, M. Calvo Gomez, P. Camargo Magalhaes, J.I. Cambon Bouzas, P. Campana, A. Campomagnani, A.C. Campos, A.F. Campoverde Quezada, Y. Cao, S. Capelli, M. Caporale, L. Capriotti, R. Caravaca-Mora, A. Carbone, L. Carcedo Salgado, R. Cardinale, A. Cardini, P. Carniti, L. Carus, R. Caspary, G. Casse, M. Cattaneo, G. Cavallero, V. Cavallini, S. Celani, I. Celestino, S. Cesare, A.J. Chadwick, M. Charles, Ph. Charpentier, E. Chatzianagnostou, R. Cheaib, M. Chefdeville, C. Chen, J. Chen, S. Chen, Z. Chen, A. Chen Hu, M. Cherif, S. Chernyshenko, X. Chiotopoulos, G. Chizhik, V. Chobanova, A. Christakakis, M. Chrzaszcz, Y. Chu, V. Chulikov, P. Ciambrone, X. Cid Vidal, P. Cifra, P.E.L. Clarke, M. Clemencic, H.V. Cliff, J. Closier, C. Cocha Toapaxi, V. Coco, A. Codovini, C. Codovini, J. Cogan, E. Cogneras, L. Cojocariu, S. Collaviti, P. Collins, T. Colombo, M. Colonna, A. Comerma-Montells, L. Congedo, J. Connaughton, A. Contu, N. Cooke, A. Corallo, G. Cordova, C. Coronel, I. Corredoira, A. Correia, G. Corti, G.C. Costantino, C. Cotirlan, J. Cottee Meldrum, B. Couturier, D.C. Craik, N. Crepet, M. Cruz Torres, M. Cubero Campos, E. Curras Rivera, R. Currie, C.L. Da Silva, X. Dai, J. Dalseno, C. D'Ambrosio, G. Darze, A. Davidson, O. De Aguiar Francisco, C. De Angelis, F. De Benedetti, J. de Boer, K. De Bruyn, S. De Capua, M. De Cian, U. De Freitas Carneiro Da Graca, F. De Gregorio, E. De Lucia, J.M. De Miranda, L. De Paula, A. De Robertis, E. De Santis, M. De Serio, P. De Simone, F. De Vellis, J.A. de Vries, F. Debernardis, D. Decamp, S. Dekkers, L. Del Buono, B. Delaney, B. Demaire-Lepape, J. Deng, O. Deschamps, F. Dettori, B. Dey, P. Di Nezza, S. Ding, Y. Ding, L. Dittmann, J.F. Diverchy, A.D. Docheva, A. Doheny, C. Dong, F. Dordei, J. Dorta Moreno, A.C. dos Reis, J. Dos Santos Oliveira, A.D. Dowling, L. Dreyfus, W. Duan, P. Duda, L. Dufour, V. Duk, P. Durante, M.M. Duras, J.M. Durham, O.D. Durmus, K. Duwe, A. Dziurda, S. Easo, E. Eckstein, U. Egede, S. Eisenhardt, E. Ejopu, L. Eklund, M. Elashri, D. Elizondo Blanco, J. Ellbracht, S. Ely, A. Ene, T. Evans, F. Fabiano, S. Faghih, L.N. Falcao, B. Fang, R. Fantechi, L. Fantini, M. Faria, K. Farmer, F. Fassin, D. Fazzini, L. Felkowski, C. Feng, M. Feng, A. Fernandez Casani, M. Fernandez Gomez, B. Fernandez Rodino, J. Fernandez-John, A.D. Fernez, F. Ferrari, F. Ferreira Rodrigues, R.A. Fini, R. Fiorenza, M. Fiorini, M. Firlej, D.S. Fitzgerald, C. Fitzpatrick, T. Fiutowski, F. Fleuret, A. Fomin, M. Fontana, M. Fontes Vaz, L.A. Foreman, R. Forty, D. Foulds-Holt, V. Franco Lima, M. Franco Sevilla, M. Frank, E. Franzoso, G. Frau, C. Frei, D.A. Friday, J. Fu, Y. Fu, Q. Führing, T. Fulghesu, G. Galati, M.D. Galati, A. Gallas Torreira, D. Galli, S. Gambetta, M. Gandelman, P. Gandini, B. Ganie, H. Gao, R. Gao, T.Q. Gao, Y. Gao, Y. Gao, Y. Gao, L.M. Garcia Martin, P. Garcia Moreno, J. García Pardiñas, P. Gardner, L. Garrido, C. Gaspar, A. Gavrikov, J. George, E. Gersabeck, M. Gersabeck, T. Gershon, S. Ghizzo, Z. Ghorbanimoghaddam, F.I. Giasemis, V. Gibson, H.K. Giemza, A.L. Gilman, M. Giovannetti, A. Gioventù, L. Girardey, M.A. Giza, F.C. Glaser, V.V. Gligorov, C. Göbel, L. Golinka-Bezshyyko, E. Golobardes, A. Golutvin, S. Gomez Fernandez, A.G. Gomez Mongui, W. Gomulka, F. Goncalves Abrantes, I. Gonçales Vaz, M. Goncerz, G. Gong, S. Gong, J.A. Gooding, C. Gotti, E. Govorkova, J.P. Grabowski, L.A. Granado Cardoso, R. Grande Quartieri, E. Graugés, E. Graverini, L. Grazette, G. Graziani, A.T. Grecu, N.A. Grieser, L. Grillo, C. Gu, M. Guarise, L. Guerry, A.-K. Guseinov, Y. Guz, T. Gys, K. Habermann, T. Hadavizadeh, C. Hadjivasiliou, G. Haefeli, C. Haen, S. Haken, G. Hallett, P.M. Hamilton, Q. Han, S. Han, X. Han, S. Hansmann-Menzemer, N. Harnew, T.J. Harris, L. Hartman, M. Hartmann, S. Hashmi, J. He, N. Heatley, A. Hedes, F. Hemmer, C. Henderson, R. Henderson, R.D.L. Henderson, A.M. Hennequin, K. Hennessy, A. Henrot, J. Herd, P. Herrero Gascon, J. Heuel, A. Heyn, A. Hicheur, G. Hijano Mendizabal, J. Horswill, R. Hou, Y. Hou, D.C. Houston, N. Howarth, W. Hu, X. Hu, W. Hulsbergen, R.J. Hunter, D. Hutchcroft, M. Idzik, P. Ilten, A. Iohner, S. Jacevicius, H. Jage, S.J. Jaimes Elles, S. Jakobsen, T. Jakoubek, E. Jans, A. Jawahery, C. Jayaweera, A. Jelavic, V. Jevtic, Z. Jia, E. Jiang, X. Jiang, Y. Jiang, Y.J. Jiang, E. Jimenez Moya, N. Jindal, M. John, A. John Rubesh Rajan, D. Johnson, C.R. Jones, S. Joshi, B. Jost, J. Juan Castella, N. Jurik, I. Juszczak, K. Kalecinska, D. Kaminaris, S. Kandybei, M. Kane, Y. Kang, C. Kar, M. Karacson, A. Kauniskangas, J.W. Kautz, M.K. Kazanecki, F. Keizer, M. Kenzie, T. Ketel, B. Khanji, S. Kholodenko, V. Kholoimov, G. Khreich, F. Kiraz, T. Kirn, V.S. Kirsebom, N. Kleijne, A. Kleimenova, D. Klekots, K. Klimaszewski, M.R. Kmiec, T. Knospe, R. Kolb, S. Koliiev, L. Kolk, A. Konoplyannikov, P. Kopciewicz, P. Koppenburg, A. Korchin, I. Kostiuk, O. Kot, S. Kotriakhova, E. Kowalczyk, O. Kravcov, M. Kreps, W. Krupa, W. Krzemien, O. Kshyvanskyi, S. Kubis, M. Kucharczyk, A. Kupsc, A. Kurzina, V. Kushnir, B. Kutsenko, J. Kvapil, I. Kyryllin, D. Lacarrere, P. Laguarta Gonzalez, A. Lai, A. Lampis, D. Lancierini, C. Landesa Gomez, G. Lanfranchi, C. Langenbruch, T. Latham, F. Lazzari, C. Lazzeroni, R. Le Gac, H. Lee, R. Lefèvre, M. Lehuraux, E. Lemos Cid, O. Leroy, T. Lesiak, E.D. Lesser, B. Leverington, A. Li, C. Li, C. Li, H. Li, J. Li, K. Li, L. Li, L. Li, P. Li, P.-R. Li, Q. Li, T. Li, T. Li, W. Li, Y. Li, Y. Li, Y. Li, Z. Li, Z. Lian, Q. Liang, X. Liang, Z. Liang, S. Libralon, A. Lightbody, J. Lin, S. Lin, T. Lin, R. Lindner, H. Linton, R. Litvinov, D. Liu, F.L. Liu, G. Liu, K. Liu, S. Liu, W. Liu, X. Liu, Y. Liu, Y. Liu, Y.L. Liu, G. Loachamin Ordonez, I. Lobo, A. Lobo Salvia, A. Loi, T. Long, F.C.L. Lopes, J.H. Lopes, A. Lopez Huertas, C. Lopez Iribarnegaray, Q. Lu, C. Lucarelli, D. Lucchesi, M. Lucio Martinez, Y. Luo, A. Lupato, M. Lupberger, E. Luppi, K. Lynch, J. Lyu, S. Lyu, X.-R. Lyu, H. Ma, S. Maccolini, F. Machefert, F. Maciuc, B. Mack, I. Mackay, L.M. Mackey, L.R. Madhan Mohan, M.J. Madurai, D. Magdalinski, J.J. Malczewski, S. Malde, L. Malentacca, G. Manca, C. Mancuso, R. Manera Escalero, A. Mangalasseri, F.M. Manganella, R. Mangrulkar, D. Manuzzi, S. Mao, D. Marangotto, J.F. Marchand, R. Marchevski, U. Marconi, L. Mareso, E. Mariani, S. Mariani, C. Marin Benito, J. Marks, A.M. Marshall, L. Martel, G. Martelli, G. Martellotti, L. Martinazzoli, M. Martinelli, C. Martinez, A. Martinez Armas, D. Martinez Gomez, D. Martinez Santos, F. Martinez Vidal, A. Martorell i Granollers, A. Massafferri, R. Matev, A. Mathad, C. Matteuzzi, K.R. Mattioli, L. Matzner, A. Mauri, E. Maurice, J. Mauricio, P. Mayencourt, J. Mazorra de Cos, M. Mazurek, D. Mazzanti Tarancon, M. McCann, N.T. McHugh, A. McNab, R. McNulty, B. Meadows, S.E.R. Medaer, D. Melnychuk, D. Mendoza Granada, P. Menendez Valdes Perez, F.M. Meng, M. Merk, A. Merli, L. Meyer Garcia, D. Miao, H. Miao, S. Mico, M. Mikhasenko, D.A. Milanes, A. Minotti, E. Minucci, B. Mitreska, D.S. Mitzel, R. Mocanu, A. Modak, L. Moeser, R.D. Moise, E.F. Molina Cardenas, T. Mombächer, M. Monk, T. Monnard, S. Monteil, A. Morcillo Gomez, G. Morello, M.J. Morello, M.P. Morgenthaler, A. Moro, J. Moron, W. Morren, A.B. Morris, A.G. Morris, R. Mountain, Z. Mu, N. Muangkod, E. Muhammad, F. Muheim, M. Mulder, K. Müller, F. Muñoz-Rojas, V. Mytrochenko, P. Naik, T. Nakada, R. Nandakumar, G. Napoletano, I. Nasteva, M. Needham, N. Neri, S. Neubert, N. Neufeld, J. Nicolini, D. Nicotra, E.M. Niel, L. Nisi, Q. Niu, B.K. Njoki, P. Nogarolli, P. Nogga, J. Nombela Royo, C. Normand, A. Novo Cal, J. Novoa Fernandez, G. Nowak, H.N. Nur, A. Oblakowska-Mucha, T. Oeser, O. Okhrimenko, R. Oldeman, F. Oliva, E. Olivart Pino, M. Olocco, R.H. O'Neil, J.S. Ordonez Soto, D. Osthues, J.M. Otalora Goicochea, P. Owen, A. Oyanguren, O. Ozcelik, F. Paciolla, A. Padee, K.O. Padeken, B. Pagare, T. Pajero, A. Palano, L. Palini, L. Palombini, M. Palutan, C. Pan, X. Pan, S. Panebianco, S. Paniskaki, L. Paolucci, A. Papanestis, M. Pappagallo, L.L. Pappalardo, C. Pappenheimer, C. Parkes, D. Parmar, G. Passaleva, D. Passaro, A. Pastore, M. Patel, J. Patoc, C. Patrignani, A. Paul, C.J. Pawley, A. Pellegrino, J. Peng, X. Peng, M. Pepe Altarelli, S. Perazzini, H. Pereira Da Costa, M. Pereira Martinez, A. Pereiro Castro, C. Perez, A. Perez Casas, P. Perret, A. Perrevoort, A. Perro, M.J. Peters, A. Petkovic, K. Petridis, A. Petrolini, S. Pezzulo, J.P. Pfaller, H. Pham, L. Pica, M. Piccini, L. Piccolo, B. Pietrzyk, R.N. Pilato, D. Pinci, F. Pisani, M. Pizzichemi, V.M. Placinta, M. Plo Casasus, T. Poeschl, F. Polci, M. Poli Lener, A. Poluektov, I. Polyakov, E. Polycarpo, S. Ponce, D. Popov, K. Popp, K. Prasanth, C. Prouve, D. Provenzano, V. Pugatch, A. Puicercus Gomez, G. Punzi, J.R. Pybus, Q. Qian, W. Qian, N. Qin, R. Quagliani, R.I. Rabadan Trejo, B. Rachwal, R. Racz, J.H. Rademacker, M. Rama, M. Ramírez García, V. Ramos De Oliveira, M. Ramos Pernas, G. Ramsey, M.S. Rangel, G. Raven, M. Rebollo De Miguel, F. Redi, J. Reich, F. Reiss, Z. Ren, P.K. Resmi, M. Ribalda Galvez, R. Ribatti, G. Ricart, D. Riccardi, S. Ricciardi, K. Richardson, M. Richardson-Slipper, F. Riehn, K. Rinnert, P. Robbe, G. Robertson, E. Rodrigues, A. Rodriguez Alvarez, E. Rodriguez Fernandez, J.A. Rodriguez Lopez, E. Rodriguez Rodriguez, J. Roensch, A. Rogovskiy, D.L. Rolf, P. Roloff, A. Romano, V. Romanovskiy, A. Romero Vidal, G. Romolini, F. Ronchetti, T. Rong, W. Rose, M. Rotondo, M.S. Rudolph, G. Ruggiero, M. Ruiz Diaz, J. Ruiz Vidal, J. Ruz Armendariz, J.J. Saavedra-Arias, J.J. Saborido Silva, D. Sahoo, N. Sahoo, B. Saitta, M. Salomoni, I. Sanderswood, R. Santacesaria, C. Santamarina Rios, M. Santimaria, L. Santoro, E. Santovetti, A. Saputi, A. Sarnatskiy, G. Sarpis, M. Sarpis, C. Satriano, A. Satta, M. Saur, H. Sazak, F. Sborzacchi, A. Scarabotto, S. Schael, S. Scherl, M. Schiller, H. Schindler, M. Schmelling, B. Schmidt, N. Schmidt, S. Schmitt, H. Schmitz, O. Schneider, A. Schopper, N. Schulte, H. Schumacher, M.H. Schune, G. Schwering, B. Sciascia, A. Sciuccati, G. Scriven, I. Segal, S. Sellam, M. Senghi Soares, A. Sergi, N. Serra, L. Sestini, B. Sevilla Sanjuan, Y. Shang, D.M. Shangase, R.S. Sharma, L. Shchutska, T. Shears, S. Shelton, J. Shen, Z. Shen, S. Sheng, B. Shi, J. Shi, Q. Shi, W.S. Shi, E. Shmanin, R. Silva Coutinho, G. Simi, S. Simone, M. Singha, I. Siral, N. Skidmore, T. Skwarnicki, M.W. Slater, E. Smith, M. Smith, L. Soares Lavra, M.D. Sokoloff, F.J.P. Soler, A. Solomin, K. Solovieva, N.S. Sommerfeld, R. Song, Y. Song, Y. Song, Y.S. Song, F.L. Souza De Almeida, G. Souza De Castro, B. Souza De Paula, K.M. Sowa, E. Spadaro Norella, E. Spedicato, J.G. Speer, P. Spradlin, F. Stagni, M. Stahl, S. Stahl, S. Stanislaus, M. Stefaniak, O. Steinkamp, F. Suljik, J. Sun, L. Sun, M. Sun, D. Sundfeld, P. Svihra, V. Svintozelskyi, J. Swallow, K. Swientek, F. Swystun, A. Szabelski, T. Szumlak, Y. Tan, Y. Tang, Y.T. Tang, M.D. Tat, J.A. Teijeiro Jimenez, F. Terzuoli, F. Teubert, E. Thomas, D.J.D. Thompson, A.R. Thomson-Strong, R. Thornton, H. Tilquin, V. Tisserand, S. T'Jampens, M. Tobin, T.T. Todorov, L. Tomassetti, G. Tonani, X. Tong, T. Tork, L. Torlai, L. Toscano, D.Y. Tou, C. Trippl, G. Tuci, N. Tuning, L.H. Uecker, A. Ukleja, A. Upadhyay, B. Urbach, A. Usachov, U. Uwer, V. Vagnoni, A. Vaitkevicius, A. Valassi, V. Valcarce Cadenas, G. Valenti, N. Valls Canudas, J. van Eldik, H. Van Hecke, E. van Herwijnen, C.B. Van Hulse, R. Van Laak, M. van Veghel, P. Varrella, R. Vazquez Gomez, P. Vazquez Regueiro, C. Vázquez Sierra, S. Vecchi, J. Velilla Serna, J.J. Velthuis, M. Veltri, A. Venkateswaran, M. Verdoglia, M. Vesterinen, W. Vetens, D. Vico Benet, P. Vidrier Villalba, M. Vieites Diaz, X. Vilasis-Cardona, E. Vilella Figueras, A. Villa, P. Vincent, B. Vivacqua, F.C. Volle, D. vom Bruch, K. Vos, C. Vrahas, J. Wagner, J. Walsh, N. Walter, E.J. Walton, G. Wan, A. Wang, B. Wang, C. Wang, C. Wang, C. Wang, G. Wang, H. Wang, J. Wang, J. Wang, J. Wang, J. Wang, M. Wang, N.W. Wang, X. Wang, X. Wang, X. Wang, X.W. Wang, Y. Wang, Y. Wang, Y. Wang, Y.H. Wang, Z. Wang, Z. Wang, J.A. Ward, A. Wasili, M. Waterlaat, N.K. Watson, D. Websdale, Y. Wei, Z. Weida, J. Wendel, B.D.C. Westhenry, A.S. White, C. White, M. Whitehead, E. Whiter, A.R. Wiederhold, D. Wiedner, M.A. Wiegertjes, C. Wild, G. Wilkinson, M.K. Wilkinson, M. Williams, M.J. Williams, M.R.J. Williams, R. Williams, S. Williams, Z. Williams, F.F. Wilson, M. Winn, W. Wislicki, M. Witek, L. Witola, T. Wolf, E. Wood, G. Wormser, S.A. Wotton, H. Wu, J. Wu, T. Wu, X. Wu, Y. Wu, Z. Wu, K. Wyllie, S. Xian, Z. Xiang, Y. Xie, T.X. Xing, A. Xu, L. Xu, M. Xu, R. Xu, Z. Xu, Z. Xu, Z. Xu, Z. Xu, S. Yadav, K. Yang, X. Yang, Y. Yang, Y. Yang, Z. Yang, Z. Yang, H. Yeung, H. Yin, X. Yin, C.Y. Yu, J. Yu, K. Yu, X. Yuan, Y Yuan, S. Zalambani, J.A. Zamora Saa, F. Zangari, M. Zavertyaev, M. Zdybal, F. Zenesini, C. Zeng, M. Zeng, S.H Zeng, C. Zhang, C. Zhang, D. Zhang, J. Zhang, L. Zhang, Q.Z. Zhang, R. Zhang, S. Zhang, S.L. Zhang, Y. Zhang, Z. Zhang, J. Zhao, M. Zhao, Y. Zhao, A. Zhelezov, S.Z. Zheng, X.Z. Zheng, Y. Zheng, T. Zhou, X. Zhou, V. Zhovkovska, L.Z. Zhu, X. Zhu, X. Zhu, Y. Zhu, V. Zhukov, J. Zhuo, T. Zies, D. Zuliani, X. Zuo

Materials Science

Configuration averaging of X-ray absorption spectra of disordered systems within the augmented-space full multiple-scattering formalism

Maurizio Benfatto

We present a formulation of the full multiple-scattering theory of X-ray absorption spectroscopy (XAS) for disordered systems based on the augmented-space method of Mookerjee. Both substitutional (chemical) and thermal (vibrational) disorder are cast, on the same footing, as exact matrix elements of a non-random operator acting on an enlarged Hilbert space. The configuration-averaged scattering-path operator is thereby obtained by inverting a non-random secular matrix, with no expansion in scattering paths, without recourse to the single-site approximation and without any assumption on the shape of the disorder distribution. This is what the quantitative analysis of the near-edge region requires: XANES lies where the multiple-scattering series does not converge, so that a treatment of disorder tied to a path expansion is unavailable there. The inversion is carried out by a continued-fraction (Lanczos) recursion, which accesses the required matrix element without constructing the full configuration basis or diagonalising the augmented operator. The operator Debye-Waller factor of the harmonic theory is recovered as the Gaussian special case, and anharmonic disorder is included with no additional machinery, through the moments of a non-Gaussian displacement distribution. Where the series does converge, the construction also settles a question of principle: for statistically independent site variables, replacing each t-matrix by its configuration average is exact only for scattering paths in which every site occurs once, and for paths that revisit a site we obtain the exact second-order correction.
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Disordered Systems and Neural Networks

Neural Quantum States for Nuclear Magnetic Resonance Spectroscopy

Bharadwaj Chowdary Mummaneni and Bo Xing

Predicting a nuclear magnetic resonance (NMR) spectrum from first principles requires propagating a quantum state of dimension $2^N$ for $N$ coupled spins, which becomes intractable beyond larger $N$. We benchmark Neural Quantum States (NQS), a class of variational quantum states expressed as an artificial neural network, as an alternative representation for this problem. Using two propagation methods, the Time-Dependent Variational Principle (TDVP) and projected time-dependent Variational Monte Carlo (p-tVMC), we compute the $^1$H spectra of four ($2 \to 5$ spins) experimentally parameterized molecules. TDVP reproduces all line positions and intensities with average spectral mean squared errors of $<10^{-3}$; p-tVMC reproduces the same features, with accuracy determined by its per-step optimization parameters. One dominant obstacle to larger systems is the steep growth of the number of integration steps with spectral bandwidth, which can be removed by propagating in the interaction frame of the chemical-shifted Hamiltonian. Retaining the same accuracy, this reduces the number of integration steps roughly eightfold for the 3-spin system and by at least an order of magnitude for the 4- and 5-spin systems, and it enables a 14-spin molecule (sucrose) to be accurately propagated via Monte Carlo sampling.
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Nuclear Theory

Nuclear $\gamma$-Ray Cascades as Markov Processes

A. Psaltis

A framework for computing $\gamma$-ray feeding probabilities in nuclear decay schemes based on absorbing Markov chains is presented. In this approach, excited nuclear states are treated as transient states and long-lived levels as absorbing states, allowing feeding fractions to be obtained exactly from the transition matrix. Experimental uncertainties are propagated via Monte Carlo sampling from Dirichlet distributions, which naturally maintains the physical constraint of unit normalization for branching-ratio vectors. This framework is applied to the key $E_r= 92$ keV resonance in the $^{25}$Mg(p,$\gamma$)$^{26}$Al reaction ($E_x = 6398$ keV), which governs the production of $^{26}$Al in hydrogen-burning environments. Combining multiple experimental datasets within a Hierarchical Bayesian framework, a ground-state feeding probability of $f_0 = 0.68 \pm 0.06~(1\sigma) \pm 0.13~(2\sigma)$ is found, and for the first time the dominant $\gamma$-decay transitions contributing to its uncertainty are identified. The formalism reproduces traditional cascade calculations while providing analytic sensitivity information and a transparent uncertainty decomposition. This approach offers a general and computationally efficient tool for propagating nuclear-structure uncertainties to astrophysical reaction rates and can be readily extended to other nuclei.
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Solar and Stellar Astrophysics

On Bimodality in the Eccentricity Distribution of Galactic Double Neutron Stars

Aldana Grichener, Paul Disberg, Ryosuke Hirai et al. (+1 more)

The detection of Galactic double neutron stars (DNSs) through pulsar timing offers a unique opportunity to probe massive stellar and binary evolution. The current observed DNS population shows a scarcity of systems at intermediate eccentricities, although the present sample does not provide statistically significant evidence for an underlying bimodal distribution. We explore whether such a feature can arise naturally from DNS formation physics and serve as a prediction for future observations. We propose that this possible bimodality can result from a non-monotonic relationship between progenitor mass and neutron star (NS) mass, provided that the second-born NS receives a sufficiently small natal kick. We illustrate this scenario using the population synthesis code COMPAS, and find that our DNS population model produces an intermediate-eccentricity deficit broadly similar to that suggested by current observations and can reproduce the observed orbital period–eccentricity distribution relatively well. We also show that most measured second-born NS masses fall within the ranges predicted by our model at the corresponding DNS orbital eccentricities, providing a complementary observational diagnostic that is less sensitive to uncertainties in the preceding binary evolution. Our results therefore predict that an eccentricity bimodality should become more apparent as the Galactic DNS sample grows.
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All authors Aldana Grichener, Paul Disberg, Ryosuke Hirai, Ilya Mandel