Cosmology and Nongalactic Astrophysics
JWST lensed quasar dark matter survey V: Hints of self-interacting dark matter from 29 quadruply imaged quasars
D. Gilman, A. M. Nierenberg, J. Gurian et al. (+21 more)
Theories of self-interacting dark matter (SIDM) predict the eventual core collapse of dark matter
halos, a process that transforms these structures into extremely efficient gravitational lenses. We present a population-level inference on the abundance of core collapsed
halos and subhalos in the mass range $10^6 - 10^{10.7} M_{\odot}$ using 29 quadruply imaged
quasars, drawing on the collective
lensing signal of many low-mass perturbers. Our structure formation model predicts the abundance of collapsed (sub)
halos as a function of
halo mass and
redshift. We quantify how our results are affected by systematic uncertainties, including the abundance of globular clusters (GCs) and subhalos, and the internal structure of deeply collapsed
halos. Our data exhibits a strong preference for core collapsed
halos in the lens model, with Bayes factors disfavoring CDM relative to SIDM ranging from 8:1 to 24:1, depending on the assumed SIDM subhalo abundance and the internal structure of collapsed
halos. Explaining our data without core collapse requires both a GC abundance well above expectations and more subhalos than predicted by $N$-body simulations. These results pose a challenge to the CDM paradigm. We present a particle physics interpretation of these results in a companion paper.
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All authors D. Gilman, A. M. Nierenberg, J. Gurian, H. Paugnat, C. Gannon, M. N. Martinez, T. Treu, K. N. Abazajian, T. Anguita, V. N. Bennert, A. J. Benson, S. Birrer, S. G. Djorgovski, S. F. Hoenig, R. E. Keeley, A. Kusenko, M. Millon, T. Morishita, L. A. Moustakas, P. Mozumdar, D. Paris, W. Sheu, D. Sluse, K. C. Wong
Quantum Physics
One-dimensional quantum Gibbs states in constant circuit depth
Saúl Pilatowsky-Cameo, Georgios Styliaris, Ainesh Bakshi et al. (+1 more)
We prove that the Gibbs state of any
spin chain can be exactly decomposed into a mixture of product states over contiguous blocks of
qubits with bounded length, at any constant temperature. As a consequence, any such Gibbs state can be prepared by local
unitary circuits of constant depth, with efficient classical preprocessing. We place strong limits on the spatial structure of thermal
entanglement: both the
entanglement depth and
entanglement width (measures of multiparticle
entanglement) are bounded by constants, while the localizable
entanglement (the bipartite
entanglement that can be generated with the aid of local measurements and classical communication) vanishes exactly beyond a constant threshold distance. Our result also has implications for
quantum thermalization: for any translation-invariant
spin-chain
Hamiltonian with nondegenerate spectral gaps, typical low-complexity pure states drawn from a maximally entropic ensemble at any constant effective temperature become locally indistinguishable from the Gibbs state upon
unitary evolution. Additionally, we obtain an analogous decomposition for fermionic systems: the Gibbs state of any 1D local fermionic
Hamiltonian is exactly a mixture of constant-depth local fermionic
circuits acting on Gaussian states.
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All authors Saúl Pilatowsky-Cameo, Georgios Styliaris, Ainesh Bakshi, Daniel Malz
High Energy Physics (Phenomenology)
Resummation of Next-to-Leading Non-Global Logarithms in Higgs Production
Thomas Becher, Rebecca von Kuk, Xinyu Qin et al. (+1 more)
We analyze
Higgs production at the LHC with a jet veto at central rapidities and present the first next-to-leading logarithmic resummation of non-global logarithms for this process. The resummation combines one-loop hard and soft matching functions with two-loop anomalous dimensions in the large-$N_c$ limit. To perform the resummation we numerically solve renormalization group equations via the parton-shower framework MARZILI. After matching to fixed order, we perform a detailed study of different sources of uncertainties. We find that the hard matching corrections dominate by far and are substantially larger than in Drell-Yan production. Together with earlier results for Drell-Yan, these are the first resummations of subleading non-global logarithms in
hadron-
collider cross sections, and they provide a
benchmark for logarithmically accurate parton showers.
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All authors Thomas Becher, Rebecca von Kuk, Xinyu Qin, Nicolas Schalch
General Relativity and Quantum Cosmology
Black Hole Quasinormal Mode Resonances and Reconnections in Coupled Systems
Leah Jenks, Hayato Motohashi, Kazufumi Takahashi et al. (+2 more)
Black hole quasinormal modes (QNMs) provide a window into the underlying structure of black holes and the environments in which they arise. QNMs have particularly rich dynamics in coupled systems beyond general relativity, in which they are known to undergo avoided crossings, resonant excitation, and mode reconnections. Recent work has shown that reconnecting QNM trajectories can trace out a distinctive double spiral structure in the complex frequency plane. In this work, we study this phenomenology in a concrete model of perturbed dynamical Chern-Simons (dCS) theory, as well as in a minimal toy model. In the former, we characterize the exceptional points, avoided crossings and reconnections for several values of the perturbation parameters, and find that the limiting frequency of the double spiral endpoints is independent of the perturbation strength. We compute the excitation factors and find that they follow the scaling characteristic of a resonance between the scalar and gravitational modes. To determine whether these phenomena depend on the specific features of dCS, we construct a toy model of coupled degrees of freedom with square potential barriers, and find that we can reproduce the avoided crossings and reconnections, indicating that these phenomena can occur more generally in coupled systems and are highly sensitive to the system parameters.
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All authors Leah Jenks, Hayato Motohashi, Kazufumi Takahashi, Takuya Takahashi, Emanuele Berti
Astrophysics of Galaxies
The 1.6 $\mu\mathrm{m}$ $\rm{H^{-}}$ bump as a diagnostic of TP-AGB contributions and recent quenching. I. Insights from stellar population models
Pengjun Lu, Song Huang, Shiying Lu et al. (+3 more)
The 1.6 $\mu\mathrm{m}$ $\rm{H^{-}}$ bump arises from a minimum in the opacity of the negative hydrogen ion in cool
stellar atmospheres. Although it is recognized as a common feature in
galaxy spectra, its potential for studying
stellar populations and recent quenching remains little explored. Its enhancement at intermediate ages is strong in some
stellar population models with substantial thermally pulsing asymptotic
giant branch (TP-AGB) contributions but weak or absent in others. This variation makes the feature both a potential age diagnostic and a source of model uncertainty. We use models based on the X-shooter Spectral Library (XSL) and Flexible
Stellar Population Synthesis (FSPS) to examine what drives this behavior and what it can reveal about quenching. Controlled FSPS experiments show that the $\rm{H^{-}}$ bump depends on both the amount of TP-AGB light and the
stellar template used to represent it. The adopted XSL and TP-AGB-on FSPS models predict a transient enhancement following rapid quenching, with a different age response from optical spectral features. Combining these diagnostics can therefore provide additional information about recent quenching, although the interpretation depends on the population model and
star-formation history. An illustrative comparison with existing JWST spectra shows that models including TP-AGB contributions can describe the observed $\rm{H^{-}}$ region reasonably well. These results motivate further use of the $\rm{H^{-}}$ bump to test TP-AGB prescriptions and investigate quenching with current and forthcoming observations.
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All authors Pengjun Lu, Song Huang, Shiying Lu, Meng Gu, Li Shen, Cheng Li
High Energy Physics (Phenomenology)
Constraining dark matter using 20-year INTEGRAL/IBIS observations II: Sub-GeV dark matter
Jordan Koechler and Pedro De la Torre Luque
We present new constraints on sub-GeV dark matter (DM) annihilation and decay using twenty years of diffuse hard X-ray observations from the INTEGRAL/IBIS
telescope. By performing a joint analysis of the spectral and morphological information contained in the IBIS
dataset, we simultaneously fit
Galactic longitudinal profiles and energy spectra, exploiting their complementary signatures to disentangle potential DM signals from the dominant astrophysical backgrounds. We use physically motivated background models combining inverse-Compton (IC) emission from
Galactic cosmic-ray electrons with thermal emission from unresolved accreting white
dwarfs, and consistently include the secondary IC emission generated by DM-induced electron and positron populations propagated through the
Galaxy. We conservatively derive 95% upper limits on the annihilation cross section $\langle\sigma v\rangle$ and decay half-life $\tau$ for the $e^+e^-$, $\mu^+\mu^-$, and $\pi^+\pi^-$ final states across the mass range 1 MeV to 5 GeV. Our constraints are in the range $10^{-28}$ cm$^3$/s $\lesssim \langle\sigma v\rangle \lesssim 10^{-26}$ cm$^3$/s for annihilation and $\tau \gtrsim 10^{25}$ s for decay at DM masses of a few MeV, improving upon existing X-ray limits by up to two orders of magnitude over much of the mass range. Our bounds are translated into constraints on the kinetic mixing parameter $\epsilon$ of a dark
photon and the scalar-
Higgs mixing angle $\sin\theta$, and compared with existing indirect, direct and accelerator limits available, providing a comprehensive picture of the allowed parameter space for light portal DM.
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Earth and Planetary Astrophysics
GameDev: GPU-accelerated model for dust evolution
Jiaqing Bi
Grain growth and fragmentation through
dust collisions in protoplanetary disks are strongly coupled with
dust dynamics. This is because the spatial and velocity distributions of
dust set the collision rates and outcomes, while
dust grain sizes set the aerodynamic coupling with gas. However, existing
dust evolution codes often rely on prescribed
dust velocities and are mostly restricted to one or two spatial dimensions. In this work, we present GameDev, a
dust evolution model accelerated by graphics processing units (GPUs) that couples independently evolved three-dimensional
dust dynamics with Monte Carlo collisional
evolution of
dust. In GameDev, we model
dust as Lagrangian representative particles in a prescribed gas disk. We integrate particle trajectories with the staggered semi-analytic method, which remains accurate for both tightly and weakly coupled
dust grains. We estimate collision rates from each particle's nearest neighbors rather than on a grid, preventing physically close particles from being excluded from collision sampling because they lie across a grid boundary. Most importantly, we sample collision events against neighborhoods that remain frozen over adaptive intervals, enabling massive parallelization across particles. These implementations make GameDev an accurate and efficient tool for studying
dust evolution in protoplanetary disks. GameDev supports both NVIDIA CUDA and AMD ROCm platforms, provides a smaller-scale standalone Eulerian
dust fluid model, and is publicly available on GitHub.
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Instrumentation and Methods for Astrophysics
SIFARI: Self-Supervised Interferometric Fitting for Astronomical Radio Imaging
Shunyuan Mao, Andrea Isella, Paris Perdikaris et al. (+2 more)
Radio-interferometric images are reconstructed from sparsely sampled visibilities, and CLEAN-based imaging can struggle with spatial filtering, complex morphologies, and uncertainty quantification. Alternative methods that fit visibilities directly can address some of these limitations but often require manual choices of image priors and model hyperparameters. We present SIFARI (Self-Supervised Interferometric Fitting for Astronomical
Radio Imaging), a self-supervised neural network workflow that represents sky brightness as a continuous function of position and fits measured visibilities without an external image training set or explicit spatial regularizer. An empirical rule sets the
Fourier feature scale from the visibilities before training, controlling how readily the network fits fine structure. Sampling network weights with
Stochastic Weight Averaging-Gaussian (SWAG) gives approximate brightness uncertainty estimates, which we combine with a thermal-noise floor to construct spatially resolved signal-to-noise maps. In synthetic ALMA tests, SIFARI yields an effective point-source response about eight times narrower than the natural-weighting CLEAN restoring beam and recovers more extended flux than CLEAN when short baselines are missing. It also achieves higher image fidelity than the restored CLEAN images in all three morphology
benchmarks. Applied to ALMA observations of PDS 70, SIFARI recovers the bright outer ring together with faint compact emission in the central cavity. For long-baseline-only WISPIT 2 data, SIFARI supplies a sky model for phase self-calibration where the CLEAN model is inadequate. The restored, self-calibrated SIFARI image has approximately 30% lower RMS noise than the CLEAN image made from the original visibilities without self-calibration.
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All authors Shunyuan Mao, Andrea Isella, Paris Perdikaris, Li-Ta Lo, Hui Li
Cosmology and Nongalactic Astrophysics
Current and Future Constraints on the Primordial Power Spectrum
Zachary Cheslog, Emily Finson, Amanda MacInnis et al. (+4 more)
The
primordial scalar power spectrum provides a powerful window onto early-universe physics, including a broad class of inflationary scenarios. These models often predict a characteristic scalar spectral index $(n_s)$, nonzero running $(\alpha_s)$, or more general deviations from a pure power-law form. We find that freeing the number of light relic species $(N_{\rm eff})$ and the sum of the
neutrino masses $(\sum m_\nu)$ broadens the $n_s$ error contours enough that key early-Universe models are no longer excluded. In particular, while both Starobinsky inflation and the Bi-thermal Big Bang model are ruled out at about the 95% confidence level in the six-parameter $\Lambda$CDM model, we find that in the nine-parameter $\Lambda{\rm CDM} + \alpha_s + N_{\rm eff} + \sum m_\nu$ model, CMB data from Planck, ACT, and SPT (CMB-PAS) combined with DESI DR2 give $n_s = 0.9758 \pm 0.0064$ and $\alpha_s = 0.0080 \pm 0.0064$, consistent with both models. Future CMB facilities will sharply improve constraints on $n_s$, $\alpha_s$, and, more generally, the binned
primordial power spectrum $\mathcal{P}(k)$. For example, CMB-PAS constrains $e^{-2\tau}\mathcal{P}(k = 0.2\,{\rm Mpc}^{-1})$ to 0.5%, while SO-like and CMB-HD-like surveys would tighten this to 0.1%; CMB-HD would also extend this measurement to smaller, previously unprobed scales, constraining $e^{-2\tau}\mathcal{P}(k = 30\,{\rm Mpc}^{-1})$ to within a factor of ten. We release our forecast code and update the public CMB-HD likelihood and Fisher codes to support CLASS in addition to CAMB.
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All authors Zachary Cheslog, Emily Finson, Amanda MacInnis, Neelima Sehgal, Niayesh Afshordi, Simran K. Nerval, Renée Hložek
High Energy Physics (Theory)
Type IIB supergravity solutions for polarized IKKT
Eric D'Hoker, Michael Gutperle and Christoph F. Uhlemann
The general local solutions to complexified Type IIB supergravity which are invariant under the complex Lie superalgebra $F(4)$, and which were derived and classified in arXiv:2508.14959, are supplemented here by the construction of their flux potentials and field strengths. We then focus on the Type IIB$^\star$ real form of complex Type IIB supergravity, where we obtain solutions with spacetime metric of the warped product form $dS_{1,5}\times S^2\times\Sigma$. We systematically derive boundary and regularity conditions under which the $dS_{1,5}\times S^2\times\Sigma$ solutions can be analytically continued to regular $S^6\times S^2\times\Sigma$ solutions in Euclidean Type IIB supergravity. Using these results, we construct explicit global solutions. These solutions include explicit realizations of recent proposals for a
holographic description of the polarized IKKT model, and we clarify the charges carried by these solutions. We also obtain novel solutions in the same regularity class with different brane charges.
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General Relativity and Quantum Cosmology
Low Frequency Gravitational Wave Detection with Gravito-Magnetism
Reza Ebadi and Surjeet Rajendran
The detection of gravitational waves in the low-frequency band (10 nHz to 1 micro-Hz) using inner
solar system proof masses is severely limited by Newtonian
gravity gradient noise (GGN) sourced by the asteroid belt. In this paper, we propose a novel detection concept that exploits the relativistic nature of gravitational waves to break the degeneracy between the signal and the asteroid GGN background. The non-relativistic motion of asteroids dominantly sources gravito-electric fields, with velocity suppressed gravito-
magnetic components. Relativistic gravitational waves produce gravito-electric and gravito-
magnetic components of equal magnitude. We propose detecting the gravito-
magnetic component of low frequency gravitational waves using the Lorentz acceleration of test bodies. The measurement of this Lorentz acceleration is metrologically possible due to the fact that expected astrophysical sources of low frequency gravitational waves have considerably higher characteristic strains than the strains typically expected at higher frequencies. We show that this measurement allows for unambiguous extraction of the gravitational wave signal from the
gravity gradient noise in a three satellite constellation. The gravito-
magnetic measurement still requires a proof mass that is well isolated from non-gravitational noise. We propose the use of atom interferometers to serve as such a pristine inertial reference.
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High Energy Physics (Theory)
Allowable complex saddles with real charges in the gravitational index
Fabio Billiato and Gianmarco Esposto
We present a new supersymmetric, non-extremal complexification of asymptotically $\mathrm{AdS}$ black holes, characterized by real charges and multiple complex horizons. We investigate whether these solutions define admissible supersymmetric saddles of the gravitational path integral by applying the Kontsevich-Segal-Witten (KSW) criterion, and compare the resulting gravitational constraints with the convergence conditions of the dual superconformal index. For most of the cases studied, the KSW criterion in the asymptotic region agrees with the index convergence, while the full bulk condition is more stringent and excludes saddles whose chemical potentials lie within the index-convergence domain.
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Strongly Correlated Electrons
Advancing Fuzzy-Sphere CFTs: $\mathrm{SO}(3)$-Rotation-Resolving Exact Diagonalization, 3D Ising Heavy Primaries, and Quasi-Hole-Space Projection
Zheng Zhou and Yin-Chen He
Fuzzy-sphere regularization has recently emerged as a powerful framework for studying three-dimensional conformal field theories (CFTs). In this work, we exploit
symmetry and
Hilbert-space structures to substantially advance this framework. We develop an exact-diagonalization
algorithm that resolves the full $\mathrm{SO}(3)$ rotational
symmetry, reducing computational costs by factors of several hundred. For the three-dimensional Ising CFT, we identify around 100 primary operators, including a large number of previously unknown heavy scalar primaries up to scaling dimension $\Delta\approx16.5$. We also resolve the tension between previous fuzzy-sphere and bootstrap results regarding the parity-odd scalar primary. Furthermore, we identify a branch of scalar primaries associated with $\phi^n$ operators in the $\phi^4$ Lagrangian description, beginning with the identity, $\sigma$, $\epsilon$, $\epsilon'$, and $\sigma'$. Their wave functions exhibit a semi-classical structure closely related to states invariant under area-preserving diffeomorphisms of the sphere. Finally, we show that critical points involving fractional
quantum Hall states can be studied within a substantially reduced
Hilbert space spanned by quasi-hole states of the corresponding model
quantum Hall wave functions like the Laughlin state. This suggests a general strategy for exploring CFTs intertwined with topologically ordered phases.
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Solar and Stellar Astrophysics
Discovery of over a thousand variable stars in Terzan 5 and Liller 1 with JWST
Kevin B. Burdge, Ilaria Caiazzo, Malina M. Desai et al. (+18 more)
The Bulge Fossil Fragments Terzan 5 and Liller 1 host some of the densest
stellar environments in the
Galaxy, yet their variable
star populations have remained largely unexplored due to crowding and heavy obscuration. Here, we identify 1,315 variable sources in these two systems in what is to our knowledge the first JWST time-series variability census of a globular cluster-like object. By differencing consecutive non-destructive reads within each NIRCam integration, we transform sample-up-the-ramp imaging into an infrared movie sampled every 21 seconds. More than a century of observations has cataloged 5,604 variables, the majority of them pulsating
stars, across 151
Galactic globular clusters. Our census alone amounts to 23 percent of that total and contains more photometrically variable binaries than had previously been cataloged in all globular clusters combined. The field of Liller 1, with zero previously known variables, now hosts 915, nearly double the count in the runner-up $\omega$ Centauri. We detect dramatic infrared variability from the Rapid Burster, revealing the counterpart sought since 1976 (see Desai et al. 2026), and blindly recover a signal coincident with the prototype redback
pulsar PSR J1748-2446A at its
radio-timed orbital period, identifying the first optical or infrared counterpart to any of Terzan 5's
pulsars. More broadly, we present a technique that recovers group-level time-series photometry from JWST observations, enabling time-domain studies with an observatory whose field of view is naturally matched to the
Galaxy's densest
stellar systems.
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All authors Kevin B. Burdge, Ilaria Caiazzo, Malina M. Desai, Cristina Pallanca, Vera L. Berger, Kaley Brauer, Matteo Correnti, Paul Draghis, Kareem El-Badry, Francesco R. Ferraro, Denis González-Caniulef, Kyle Kremer, Barbara Lanzoni, Dongzi Li, Jessica R. Lu, Geoffrey Mo, Mason Ng, Roger W. Romani, Kaitlyn Shin, Daniel R. Weisz, Giorgia Zullo
High Energy Physics (Theory)
Solver Agent: an Agentic AI Framework for Theoretical Physics Computations Applied to F-theory Uplifts of O3-planes and S-folds
Eliott Morgensztern, Cesar Fierro Cota and Alessandro Mininno
We introduce Solver
Agent, an AI framework based on large
language models for calculations and proofs in mathematics and theoretical physics. The solution process is tracked through a persistent ledger that records assumptions, derivations, and computations. A central
agent delegates tasks to specialized sub-
agents, while independent
agents verify both intermediate steps and the final result. This setup improves the traceability, reproducibility, and verification of computer-assisted calculations. Applying Solver
Agent, we study global F-theory uplifts of Type IIB orientifolds and their S-fold generalizations. We establish sufficient conditions for Weierstrass models over projective threefolds with terminal $\mathbb{Z}_k$ quotient singularities ($k\in\{2,3,4,6\}$) to give $\mathbb{Q}$-factorial projective elliptically fibered Calabi-Yau fourfolds with isolated Gorenstein terminal quotient singularities. These geometries realize O3-planes and S-folds, where local D3-brane probes of the latter yield four-dimensional $\mathcal{N}=3$ superconformal field theories. Using stringy invariants, we derive fixed-point contributions to Hodge data and Euler characteristics, and show that these Euler corrections determine the localized D3-brane charges required for tadpole cancellation. We illustrate these results using toric hypersurface constructions, where a single three-dimensional polytope determines both the Type IIB Calabi-Yau threefold and the F-theory base; here, the orientifold double cover naturally forms a bisection of an alternative genus-one-fibered uplift with discrete $\mathbb{Z}_2$ gauge
symmetry. Finally, we provide methods for toric computations and four-form flux analysis in four-dimensional $\mathcal{N}=1$ compactifications with non-abelian gauge sectors.
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Cosmology and Nongalactic Astrophysics
LIMFAST. V. Probing Reionization with the Synergy Between 21 cm and Photometric Galaxy Surveys
Guochao Sun, Adam Lidz, Tzu-Ching Chang et al. (+4 more)
Cross-correlating the 21\,cm signal from intergalactic neutral hydrogen with the
galaxy distribution is a powerful probe of the Epoch of Reionization and the physical mechanisms driving it. While upcoming surveys with the SKA-Low
radio telescope and the Roman Space
Telescope offer ideal synergies for this measurement, foreground mitigation of 21\,cm data requires exquisite
redshift precision of
galaxies, effectively excluding the rich photometrically selected samples of Lyman-break
galaxies (LBGs) with typical
redshift uncertainties $\sigma_z \gtrsim 0.1$. We overcome this challenge using a squared statistic of the foreground-cleaned 21\,cm signal. Squaring the filtered 21\,cm signal couples surviving high $k_\parallel$ modes into low $k_\parallel$ fluctuations accessible to photometric LBG surveys. This higher-order cross-correlation statistic remains measurable even when direct cross-correlations are strongly suppressed. Applying Fisher
matrix analysis to this LBG–21\,cm$^2$ cross-correlation signal simulated by the LIMFAST code over $6 \lesssim z \lesssim 10$, we investigate the prospects for constraining EoR physics combining SKA-Low 21\,cm measurements and Roman photometric
galaxy samples. For an overlapping survey area covering 10\,deg$^2$, we find that the LBG–21\,cm$^2$ cross-correlation is detectable at high significance across much of the EoR through 1000\,hours of SKA-Low integration with 15\,MHz bandwidth and a Roman photometric
galaxy sample from the High-Latitude Wide-Area Survey (HLWAS) reaching $m_\mathrm{AB,lim}=27$ and photo-$z$ uncertainties of $\sigma_z \sim 0.1$–0.3. The characteristic sign
evolution of the large-scale cross-power spectrum—driven primarily, though not exclusively, by the evolving neutral fraction—provides strong constraints on the physical parameters governing the ionization and thermal history of the IGM.
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All authors Guochao Sun, Adam Lidz, Tzu-Ching Chang, Claude-André Faucher-Giguère, Steven R. Furlanetto, Aritra Kundu, Jordan Mirocha
High Energy Astrophysical Phenomena
Discovery of the Infrared Counterpart of the Rapid Burster with JWST
Malina M. Desai, Kevin B. Burdge, Cristina Pallanca et al. (+8 more)
The Rapid Burster (MXB 1730$-$335) is the only known
neutron star to produce both Type I and Type II X-ray bursts, making it a key system for understanding
accretion physics onto
neutron stars. It resides in Liller 1, a dense, metal-rich
stellar system whose crowded core and $\sim$11 magnitudes of visual extinction have concealed the Rapid Burster's optical/infrared (OIR) counterpart for nearly five decades. Here, we present infrared observations of Liller 1 obtained with JWST/NIRCam that, for the first time, reveal the unambiguous OIR counterpart to the Rapid Burster. Caught in an X-ray active state, the counterpart exhibits dramatic infrared variability, fading by $\sim$ 2.5 magnitudes in JWST's F200W band (1.755$-$2.227 $\mu$m) with strong fluctuations on minute timescales. These observations provide an infrared anchor for the Rapid Burster and open the way for future spectroscopy and simultaneous IR and X-ray monitoring to constrain the donor's spectral type and the system's
accretion physics.
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All authors Malina M. Desai, Kevin B. Burdge, Cristina Pallanca, Saul Rappaport, Francesco R. Ferraro, Barbara Lanzoni, Mason Ng, Paul Draghis, Emma T. Chickles, Ilaria Caiazzo, Deepto Chakrabarty
Atmospheric and Oceanic Physics
A neural network-based Universal Thermal Climate Index for reliable global thermal-stress classification across extreme weather
Bikem Pastine, Milan Klöwer, Tianning Tang et al. (+2 more)
Extreme temperatures are the leading cause of
climate-related mortality world-wide.
Climate-health research and operational weather
forecasting require accurate estimates of human thermal stress. The Universal Thermal
Climate Index (UTCI) is among the most sophisticated and widely used feels-like temperature metrics. However, its ubiquitous
polynomial approximation does not generalize well to extreme weather conditions. Here, we introduce Neural-UTCI, a neural network that calculates UTCI with substantially higher accuracy across global conditions at a lower computational cost for operational use. Neural-UTCI reduces the
polynomial approximation RMSE from 2.78{\deg}C to 0.36 {\deg}C, an 87% improvement, and lowers thermal stress misclassification rates from 5.3% to 1.7%, with consistent performance across resampling experiments. These differences affect thermal exposure metrics. For example, during the 2003 European heatwave summer in Rome, Italy, the number of very strong heat stress days increases from 15 to 35 days when using Neural-UTCI compared to operational products like ERA5-HEAT. Simultaneously, Neural-UTCI reliably classifies extreme cold stress conditions, allowing continuous global application. By improving UTCI accuracy, Neural-UTCI can strengthen
climate-health risk assessments and public weather warning systems, especially as global warming increases the incidence of extreme events.
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All authors Bikem Pastine, Milan Klöwer, Tianning Tang, Sarah Wilson Kemsley, Louise Slater
Astrophysics of Galaxies
GA-NIFS view of LAP1: Assembly of Pop~III stellar clusters during EoR
J. Scholtz, R. Maiolino, S. Carniani et al. (+28 more)
Lensed and Pristine 1 (LAP1) is one of the most promising candidates for the detection of so-called Pop~III
stars at $z\sim6.6$. In this work, we present new high-spectral-resolution ($R \sim 2700$) \jwst NIRSpec-IFS observations of the system along with a detailed re-analysis of all archival \jwst and VLT/MUSE data. We confirm the very low
metallicity of the system, with $12+\log(\text{O/H})=6.5\text{--}6.8$ (1–2% Z$_{\odot}$), and its low
stellar mass, with $M_{*}= 10^{3\text{--}4}$ \Msun, based on the non-detection in \jwst/NIRCam filter stacks and the \Hbeta luminosity. The high-resolution IFS data allow us to constrain the upper limits on the dynamical masses ($\log_{10}(M_{*}/M_{\odot})$) of the A and B components to $<6.6\text{--}7.6$ and $<5.6\text{--}6.6$, respectively. Based on the
metallicity and the high equivalent width of \Halpha (EW $>1200$\,Å), we estimate the possible range of the LAP1
stellar population ages to be $2\text{--}5$~Myr, consistent with the first burst of
star formation in a pristine environment. Based on the size ($<10$~pc) and mass of the system, we discuss the nature of LAP1 as representing the formation of the first
stellar clusters in a larger undetected
galaxy, similar to other low-
metallicity Pop~III candidates in the literature.
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All authors J. Scholtz, R. Maiolino, S. Carniani, E. Vanzella, R. J. Terlevich, H. Übler, M. Perna, S. Arribas, E. Bertola, P. Bergamini, T. Böker, A. Bolamperti, A. Bunker, S. Charlot, M. Curti, F. D'Eugenio, C. Grillo, L. R. Ivey, X. Ji, G. C. Jones, M. Meneghetti, M. M. Messa, R. Pascalau, B. Rodríguez Del Pino, P. Rosati, E. Rusta, S. Salvadori, E. Terlevich, G. Venturi, S. Zamora, A. Zanella
Astrophysics of Galaxies
Massive Population III Galaxies Near a GN-z11 Analog: The Role of the Baryon-Dark Matter Streaming Velocity
Eli Visbal, Greg L. Bryan and Ryan Hazlett
Recently the James Webb Space
Telescope (JWST) detected Hebe, a Population III (Pop III) candidate located ${\sim}3$ kpc in projection from the massive $z=10.6$
galaxy GN-z11. This raises the question of whether Pop III
star formation is expected in the vicinity of massive high-
redshift galaxies or whether it would be prevented by early metal enrichment. We address this with a semi-analytic model of Pop III and metal-enriched
star formation applied to a zoom-in N-body simulation of a highly overdense region surrounding a GN-z11 analog. The zoom-in region resolves the minihalos where the first
stars form. We find that Pop III and metal-enriched
star formation both occur earlier, and with a higher
star formation rate density, than in a typical mean-density environment. The majority of Pop III
star formation in minihalos ends by $z\sim15$; however, we identify a distinct population of late-forming Pop III
galaxies that form near the central
galaxy. These systems have their
star formation delayed due to ionizing feedback from the central GN-z11 analog and experience a Lyman-Werner (LW) intensity of ${\sim}10$ - $100~J_{21}$, potentially leading to massive Pop III starbursts similar to Hebe. Interestingly, the abundance of these Pop III
galaxies depends strongly on the
baryon-dark matter streaming velocity, $v_{\rm bc}$, because a higher streaming velocity allows
halos to remain chemically pristine for longer. None of these late-forming Pop III sources occur for $v_{\rm bc}=0$, while many form at high $v_{\rm bc}$. Averaging over the expected distribution of streaming velocities, we predict that of order four GN-z11-like
galaxies would need to be surveyed at $z\sim11$ to expect to find one such source. We also note these environments may provide a natural formation site for heavy black hole seeds.
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Disordered Systems and Neural Networks
Discrete Scale Invariance of Ising Mesons
Denis V. Vasilyev and Abbas Ali Saberi
Discrete scale invariance often arises from resonant few-body or singular scale-invariant dynamics. We show that it can instead emerge in the internal motion of a composite excitation in an ordered
quantum magnet. In the marginal $1/r^4$ transverse-field Ising chain, long-range bonds generate an asymptotic inverse-square attraction between dressed domain walls, with strength fixed by the spontaneous magnetization. The dressed two-kink threshold
curvature sets the relative kinetic scale. Together, these independently accessible quantities determine the scale-anomaly exponent and hence the
meson hierarchy. In the supercritical regime, the same exponent governs
geometric binding-energy and size ratios, logarithmic level accumulation, and log-periodic threshold scattering. Full-
spin exact diagonalization and a fourth-order weak-field
Hamiltonian support the coupled energy–size scaling in the finite window between core and ring effects. This provides a microscopic many-body realization of
quantum limit-cycle physics, with its universal scaling fixed by
magnetic order and kink mobility.
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Astrophysics of Galaxies
Photoelectron and electron microscopy investigation of laboratory grown Mg-silicate space dust analogues
Steffen Friis Holleufer, Mie Andersen, Frederik Granzow Doktor et al. (+9 more)
The atomic structure at the surface of interstellar silicate
dust particles likely plays a key role in a variety of chemical processes occurring in
star- and
planet-forming regions of the interstellar medium (ISM). Here, we use the photoelectric effect to characterize, in situ, the local chemical structure of Mg-silicate nanoparticulate films, and ex situ electron microscopy to trace changes to morphology resulting from different starting compositions. Nanoparticulate films are prepared via co-deposition of Si, Mg and O atoms on a graphitic substrate under ultra-high
vacuum (UHV) and are characterised with X-ray photoelectron spectroscopy and near edge X-ray absorption fine structure measurements. Analysis, supported by density functional theory calculations, shows that adjusting the Mg-to-Si ratio from 3.5 to 1.8 changes particle composition from a mixture of MgO and Mg-silicate towards predominantly Mg-silicate. Annealing in UHV also pushes the composition towards Mg-silicate, however, non-stoichiometric chemical motifs are always observed, presenting a distribution of potentially catalytically active sites. Electron microscopy images show composition-dependent film morphologies that restructure differently upon thermal annealing. The Mg-silicate nanoparticulate films presented here are characterised as a 2D version of ISM analogue
dust particles prepared via
laser ablation and are therefore a more readily suitable model for surface science investigations into the catalytic properties of interstellar Mg-silicate
dust.
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All authors Steffen Friis Holleufer, Mie Andersen, Frederik Granzow Doktor, Lars Eric Borchert, Martin Wibrand Larsen, Duncan S. Sutherland, Zheshen Li, Alexei Preobrajenski, Jeppe Vang Lauritsen, Cornelia Jäger, Liv Hornekær, Andrew Cassidy
Cellular Automata and Lattice Gases · Cross-listed from cs.FL
Finite-ring obstructions for quadratic binary radius-two cellular automata
Houqiao Fu
We study one-dimensional binary cellular automata with a five-slot radius-two local rule of exact algebraic-normal-form degree two, acting on periodic rings of length n. We prove that every such rule is non-injective whenever 4 | n and n >= 8. The proof begins with the four-
cell collapse, where the two extreme formal slots coincide. A structural classification of the resulting four-variable maps separates the 65,472 exactly quadratic rules into 63,456 rules with an immediate ring-four collision and 2,016 exceptional lifts. The latter split into layers of sizes 480 and 1,536. Their remaining finite obligations are represented by 136 parameter-region constructions and 768 per-lift records, respectively. Each certificate supplies differentiating closed walks of lengths 8 and 12 with a common pair-graph base vertex. Concatenation then gives lengths 8a + 12b, which are exactly the multiples of four from eight onward. The load-bearing finite certificate core therefore contains 904 = 136 + 768 independently replayable objects checked by standalone, non-searching programs. The complete checker CLIs additionally reconstruct expected populations and execute coverage, complement, and regression/guard checks; 904 is not a count of total checker operations. Periodic extension also yields full-shift non-injectivity; that consequence is used here only as a corollary.
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Fluid Dynamics
A Tensorial Extension of Fractional Dissipation at Inertial Scales
José I. H. López
We formulate a scale dependent tensorial extension of a fractional dissipation operator motivated by a macroscopic Navier Stokes correspondence. The starting point is a fractional model in which the order of dissipation decreases continuously from the
Laplacian value toward the Kolmogorov value as a local Reynolds number increases. At the critical value of the local Reynolds number, the model reduces to an isotropic operator. We then ask whether the same macroscopic description can be continued into a regime in which velocity fields have Onsager, critical or subcritical regularity without introducing an unrelated closure or an additional isotropic dissipation scale. In addition, we extend the original AFNS free, energy, construction by one nonnegative concentration order parameter c. The new term is quadratic in c and linearly coupled to the defect beta function, so that minimization leaves the original AFNS free energy exactly unchanged when the concentration branch is inactive. The resulting three regime mosaic is regular, inertial, and concentrated/anomalous. The construction uses the coarse-grained stress and its critical normalization. The normalized anisotropy tensor provides the lowest order objective tensorial information available at the critical scale, while the scale derivative of the Duchon Robert energy defect, supplies a scalar measure of departure from the Onsager threshold. We propose the minimal constitutive deformation of the critical operator: in Weyl quantization, the isotropic fractional symbol is dressed by this exponential tensorial factor, giving a pseudodifferential operator that reduces to the scalar critical operator. The exponential parametrization guarantees positive
eigenvalues and unit determinant for symmetric traceless, so the deformation redistributes dissipation among directions without introducing a new isotropic amplitude.
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General Relativity and Quantum Cosmology
Operational Meaning of the Cosmological Evolution of Dimensional Quantities: A Generalized Cosmological Time Framework for Cross-Epoch Comparisons
Seokcheon Lee
The numerical value of a dimensional constant depends on the adopted units, so its isolated temporal variation is not by itself a unit-invariant observable. We reconsider this issue in Robertson–Walker spacetime, whose homogeneous and isotropic geometry admits temporal reparametrization freedom along the fundamental congruence. Generalized Cosmological Time retains a common cosmological time parameter T_G and defines the temporal-rate factor N_G = d tau/d T_G, with the proper-time representation as the unit-rate member. In this formulation, the temporal-rate relation is embedded in the standard hypersurface-orthogonal RW congruence structure, while coordinate lapse freedom is kept distinct from the retained temporal parameter and from the phenomenological meVSL assignment. In meVSL, N_G(a) = a^(b/4), with the same b governing correlated cross-epoch scalings of dimensional quantities. Cosmological time dilation provides the explicit timing application: Delta tau_o = (1+z) Delta tau_e, while the same null-linked intervals in T_G satisfy Delta T_G,o/Delta T_G,e = (1+z) N_G,e/N_G,o. If the intrinsic timescale used to compare sources across
redshift is defined in T_G, the present normalization N_G,o = 1 gives (1+z)^(1-b/4); if defined in proper time, the usual (1+z) law is recovered. Observational tests of the correlated meVSL scalings require complete model predictions rather than constraints on isolated dimensional quantities.
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Instrumentation and Methods for Astrophysics
Reconstructing Implicit Scientific Knowledge: Evaluating LLM Agents through End-to-End Reproduction of Astronomy
Yuehui Wang, Xinyu Qi, Guirong Xue et al. (+4 more)
The integration of large
language models (LLMs) into scientific workflows is accelerating, yet their ability to reconstruct the
reasoning underlying published research remains unexplored. Papers specify explicit procedures while leaving many methodological dependencies-data selection, calibration corrections, priors, and domain assumptions-implicit. This ambiguity complicates the evaluation of LLM-based
agents, since a failure to reproduce a result may reflect either limitations of the
agent or underspecification in the source. We present a framework that evaluates
agents through end-to-end reproduction, separating execution from verification and computational failure from methodological ambiguity. We apply it to fourteen astronomy studies: a case study from The Astrophysical Journal and thirteen papers published in Nature. Eleven of the thirteen contained an ambiguity preventing a uniquely specified reproduction path. In a controlled case study, twelve predefined paths, a 3x2x2 sensitivity analysis over sample definition, sky masking, and parallax zero-point treatment-gave estimates from 2.16 to 3.53 kpc for the same quantity, with only one recovering the published value (about 2.70 kpc). The published value was never used as an optimization target, selection criterion, or stopping condition; the matching path was found only after all twelve had run. Crucially, the decisive information (a +0.02 mas parallax zero-point correction) was already in the paper, but the
agents did not recognize its causal relevance until the analysis made the effect visible. Matching a published outcome therefore does not validate reconstruction of the underlying
reasoning, and the bottleneck is as often a failure to connect relevant information as to retrieve it. End-to-end reproduction thus serves both as a test of reproducibility and as a framework for evaluating implicit scientific knowledge in AI systems.
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All authors Yuehui Wang, Xinyu Qi, Guirong Xue, Cheng Wang, Yangbin Xie, Xiaoyu Tang, Cong Sun
General Relativity and Quantum Cosmology
From Density to Mass: A New Parametrized Framework for Dark Matter Environment Around Black Holes
Rajes Ghosh, Nicholas Speeney, Avijit Chowdhury et al. (+3 more)
Astrophysical black holes (BHs) are not isolated
vacuum objects but are expected to reside within complex environments, such as dark matter (DM)
halos and baryonic distributions. Such environments can modify the spacetime geometry surrounding the BH and leave observable imprints on gravitational-wave (GW) signals, including shifts in the quasinormal mode (QNM) spectrum,
tidal Love numbers (TLNs), and the inspiral dynamics of extreme-mass-ratio inspirals (EMRIs). We develop a general framework for describing DM-dressed BH spacetimes by parameterizing the geometry directly in terms of the enclosed mass function, rather than the traditional density-based profile. This mass-based formulation is naturally connected to the total gravitational field, accommodates several common
halo profiles as limiting cases, and incorporates basic physical consistency requirements such as regularity, causality, and appropriate asymptotic behavior. Within this framework, we investigate the environmental imprints on QNMs, TLNs, and GW fluxes from EMRIs. We find a complementary sensitivity to the
halo structure: QNMs predominantly probe the inner regions of the environment, whereas static TLNs are more sensitive to its outer structure. EMRI fluxes, in contrast, probe the matter distribution through its influence on the orbital motion and GW propagation. Our results establish the enclosed-mass formulation as a flexible and physically controlled framework for connecting astrophysical environment models with precision GW observables.
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All authors Rajes Ghosh, Nicholas Speeney, Avijit Chowdhury, Chiranjeeb Singha, Miguel A. S. Pinto, Emanuele Berti
Cosmology and Nongalactic Astrophysics
Can Fingers of God be Resummed?
Shi-Fan Chen and Alejandro Aviles
Fingers of God (FoGs), Doppler shifts due to the small-scale virial motions of
galaxies, are one of the most significant challenges for analytic models of
galaxy clustering in
redshift surveys. In the effective field theory approach, the characteristic scale of these shifts introduces a new, large length scale, limiting the reach of the theory. This has motivated many phenomenological models of FoGs in the literature where their effect is approximated by a single damping function of the line-of-sight wavenumber $\lambda=k\mu$, effectively resumming powers of $\lambda$ due to single-point contractions of small-scale velocities. The goal of this work is to investigate whether such a resummation can be rigorously constructed. We show that common damping models can be understood as the mean-field limit of the single-particle characteristic function (SPCF) of FoG velocities, but that the environmental dependence of the SPCF generates equally large corrections that break the simple damping form. We develop the long-wavelength theory of the SPCF, showing that it admits an expansion in anisotropic bias operators closely related to those derived for selection effects, but with $\lambda$-dependent coefficients satisfying selection rules. We estimate these coefficients using the
halo model for DESI-like
galaxies, showing that they make significant contributions at the level of the 2- and 3-point functions of
galaxies. To answer the titular question: potentially, but at the cost of significantly expanding the operator basis and promoting free coefficients to free functions.
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Cosmology and Nongalactic Astrophysics
Gauge Backreaction in Standard Model Warm Inflation
Rafid H. Dejrah and Anish Ghoshal
Standard-Model warm inflation (SMWI) makes QCD the microscopic origin of inflationary dissipation, so the real-time response of the gauge
plasma enters the cosmological prediction. We show that a slowly relaxing gauge-helicity response cannot, in general, be absorbed into an effective friction coefficient and must instead remain dynamical. We therefore evolve the
quark axial densities and a matched hard-helicity mode, with QCD sphalerons and an effective $2\leftrightarrow3$ channel generating both charge transfer and correlated
stochastic sources in the full perturbation covariance system. The resulting backreaction is substantial but mainly indirect: gauge-helicity screening can reduce the warm dissipation ratio by an order-one fraction on the strong branch, while the $2\leftrightarrow3$ channel contributes only $0.2\%-0.7\%$ of the zero-density sphaleron friction directly, shifting the amplitude-normalized trajectory in both $n_s$ and $r_{\rm vac}$. The relevant trajectories, however, lack a parametrically broad hard-soft hierarchy and extend beyond strict linear response. The predictions should therefore be understood within the stated local Gaussian transport closure; a parameter-free Standard-Model (SM) result requires finite-affinity real-time $SU(3)$ drift, susceptibility, and noise kernels.
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High Energy Physics (Phenomenology)
Covariant Contrastive Learning for Uncertainty-Aware Anomaly Detection
Shelley Tong, Philip Harris and Gaia Grosso
Machine-learning-based anomaly detection (AD) offers a promising, model-agnostic alternative to traditional LHC analyses, allowing to search for many signals at once. Recent advances in representation learning motivate the use of neural
embeddings to map high-dimensional physics observables into low-dimensional latent spaces better suited to statistical inference. However, the propagation of systematic uncertainty in embedded spaces remains poorly understood, severely limiting the application of these methods to real LHC analyses. We address this gap with a machine learning strategy that uses a likelihood-based regularization to improve the structure of embedded spaces. Building on previous work using supervised contrastive learning for physics-aware
embeddings, our approach trains them jointly with a downstream parameterized classification task that incorporates continuous uncertainties as nuisance parameters. This method returns a latent space that covaries predictably with systematic shifts, and a model of such distortions that can be exploited in the downstream statistical test for anomaly detection. Using simulated CMS Level-1 trigger data, we show that our method successfully models continuous uncertainties in a 4D latent space with a linear parametric downstream classifier, improving both the interpretability and robustness of the statistical anomaly detection task. This framework offers a general way to study and control systematic uncertainties in latent spaces, opening the way to a new scalable statistical analysis workflow for anomaly detection at the LHC, and other high energy physics experiments.
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