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Monday 15 June

Astrophysics of Galaxies

Hector Galaxy Survey: Optical IFU and Chandra Reveal a Low-Luminosity AGN Behind Extended LINER Emission

Kyuseok Oh, Gabriella Quattropani, Pratyush Kumar Das et al. (+25 more)

We present evidence that the Hector Galaxy Survey galaxy C901005481609968 ($z_{\rm cl}=0.0553$), which exhibits spatially extended LINER-like emission in optical integral-field spectroscopy (IFS), hosts a low-luminosity active galactic nucleus (LLAGN) that contributes substantially to its ionization budget. Although the galaxy is not selected as an AGN by mid-infrared AGN color criteria, archival Chandra data reveal a compact nuclear X-ray source with $\log L_{\rm X}\approx41.46$ erg/s, supporting the presence of an LLAGN. Spatially resolved emission-line diagnostics show LINER-like line ratios across most spaxels with $\mathrm{S/N} \geq 3$, while spatially resolved $\tau$ maps ($\tau \equiv Q_{\rm pAGB}/Q_{\rm req}$) indicate a widespread photon deficit ($\log\tau<0$ over most of the mapped region), even under the most optimistic pAGB normalizations, the nuclear region remains at $\tau < 1$. Line-ratio–kinematic tests find no evidence for shock-dominated excitation as the primary driver of the extended emission, although a localized or sub-dominant shock contribution cannot be ruled out with the present data. We use this galaxy as a pilot case because the combination of Hector IFS and an independent nuclear X-ray constraint provides a stringent validation of the spatially resolved photon-budget framework. Our results indicate that evolved stellar populations alone cannot account for the observed emission, that an additional nuclear ionizing source is required at least in the inner region, and that a weak LLAGN likely contributes to the ionizing budget, particularly in the inner region. Our results demonstrate that extended LINER-like emission can conceal a substantial LLAGN contribution even when traditional optical and infrared AGN indicators are weak, and that spatially resolved photon-budget tests combined with X-ray constraints can effectively reveal such hidden activity.
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All authors Kyuseok Oh, Gabriella Quattropani, Pratyush Kumar Das, Minje Beom, Joon Hyeop Lee, Oğuzhan Çak{\i}r, Andrei Ristea, Hyunjin Jeong, Jiwon Chung, Michael J. Koss, Scott M. Croom, Mina Pak, Matt S. Owers, Sarah M. Sweet, Jong Chul Lee, Julia J. Bryant, Sree Oh, Jesse van de Sande, Peixin Zhu, Stefania Barsanti, Madusha L. P. Gunawardhana, Sujeeporn Tuntipong, Robert Content, Jon Lawrence, Ayoan Salim Sadman, Will Saunders, Barnaby Norris, Gurashish Singh Bhatia

High Energy Physics (Theory)

Supersymmetric geometry in non-supersymmetric effective field theory

Nathaniel Craig, Andrew Fee and Yu-Tse Lee

We develop a geometric framework for non-supersymmetric effective gauge theories based on their nonlinear supersymmetrizations. We construct supersymmetric embeddings for most operators up to dimension six from constrained chiral and vector superfields, and formulate vector bundles using the superfields to systematically organize the operators under field redefinitions in the gauge sector. This formalism manifests a complex geometry underlying gauge operators and accommodates redefinitions across different spins.
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Earth and Planetary Astrophysics

Angular Momentum Transport in Protoplanetary Disks

Xue-Ning Bai

We review our current understanding on the physical processes that govern angular momentum transport and evolution of protoplanetary disks. Extremely rich in physics, these processes are intimately connected to disk gas dynamics, with profound implications for planet formation. We organize them into a three-level hierarchical framework: (1) The coupling of gas with magnetic fields and radiation sets the microphysical foundation for understanding protoplanetary disk dynamics. Key ingredients include non-ideal magnetohydrodynamic effects (requiring ionization chemistry), along with heating and cooling processes. The disk can be divided into three radial sectors governed by distinct microphysics. (2) Protoplanetary disks host diverse gas dynamical processes, including hydrodynamic, magnetic and gravitational instabilities, along with thermally and magnetically-driven disk winds. Many of these individual processes are reasonably well understood, while others still require detailed investigation. (3) Protoplanetary disks are highly complex ecosystems where multiple processes interact. It is recognized that the bulk disk exhibits weak turbulence, with magnetically-driven wind likely serving as the primary transport mechanism. However, our knowledge remains highly limited regarding the disk's innermost region, early stages, long-term evolution, and environmental effects.
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High Energy Physics (Theory)

Extended Supergravity Needs String Scale Cut-off

Ashoke Sen

Many string compactifications down to four non-compact space-time dimensions with N=8, N=6 and N=4 supersymmetry have BPS black holes carrying pure D-brane charges and preserving four supersymmetries. The string coupling does not flow in these backgrounds and can be set to any arbitrary value. Therefore the supersymmetric index of these black holes must be independent of the string coupling. On the other hand, explicit computation of one loop correction to the index from gravitational path integral is sensitive to the choice of ultraviolet cut-off. We show that if the cut-off scale is chosen to be the string scale in accordance with the rules of string theory, then the dependence of the index on the string coupling disappears in accordance with the expectation from supersymmetry. Similar results are obtained for type II string theories compactified on Calabi-Yau manifolds with zero Euler number. For non-zero Euler number we encounter a puzzle that we discuss but do not fully resolve.
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Nuclear Theory

Quantum Resources and Wigner Symmetry in Nucleon-Nucleon Scattering from Effective Field Theory

Ian Low, Thomas R. Richardson and Sokratis Trifinopoulos

We study quantum resources in the spin degrees of freedom, such as entanglement, stabilizer magic, and non-local magic, in low-energy nucleon-nucleon scattering through next-to-leading order in pionless effective field theory. Treating each nucleon spin as a qubit, we calculate the corresponding resource-generating powers of the scattering operator at generic center-of-mass momentum and scattering angle $\Theta$. The analysis retains $S$- and $P$-wave channels generated by two-derivative contact interactions. When the microscopic physics exhibits Wigner's $SU(4)$ spin-flavor symmetry, the neutron-proton amplitude becomes proportional to the spin-space identity operator and therefore generates no new resources after scattering, extending an observation previously made for leading-order $S$-wave scattering. The same-nucleon channel remains resource-generating because constraints from identical particles project out part of the Hilbert space. These results show how enhanced symmetries, partial-wave structure, and resource generation are intertwined in low-energy two-body scattering.
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High Energy Physics (Theory)

When Renormalisation Remembers: UV/IR Mixing as an Entanglement Bridge

Steven Abel

Renormalisation is traditionally understood to be a Wilsonian memoryless process in which ultraviolet (UV) degrees of freedom gradually decouple, leaving an autonomous infrared (IR) description. However this need not be the case: in UV/IR mixed theories correlations between widely separated scales can persist. In this work I recast UV/IR mixing as a Hilbert-space phenomenon, realised as correlations across renormalisation scales. This formulation is implemented using the Born-Reciprocal Tensor Network (BRTN), a new configuration of tensor network that is globally symmetric under phase-space reciprocity. On this network I prepare the vacuum and reproduce the expected radiative corrections. The resulting renormalisation geometry exhibits memory, with a bridge linking reciprocal representations of IR physics, whose cross-bridge entanglement provides a precise criterion for the viability of an effective description. I analyse when this criterion is met, and show that there is a large-volume limit, with the fundamental scale held fixed, in which the obstruction to a local description scales away: Wilsonian behaviour is restored and renormalisation forgets. The BRTN therefore provides a concrete and calculable platform for UV/IR mixing.
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Astrophysics of Galaxies

MEGA and SMILES Find Fewer Dusty Galaxies than Expected at Cosmic Noon

Bren E. Backhaus, Allison Kirkpatrick, Kurt Hamblin et al. (+10 more)

We present infrared (IR) luminsosity functions (LFs) and resulting star formation rate densities using the JWST Mid-infrared Instrument (MIRI) observations from the MIRI EGS Galaxy and AGN (MEGA) survey and Systematic MIRI Legacy Extragalactic Survey (SMILES). JWST allows us to perform a robust analysis on the faint end of the IR LF beyond the local universe. We directly measure the 7.7$\mu$m polycyclic aromatic hydrocarbon (PAH) feature using either F1000W, F1500W, or F2100W photometry. This results in a sample of 634 galaxies across the two surveys covering an area of 105 arcmin$^2$ ($\sim$70 in the EGS and $\sim35$ in the GOODS-S/HUDF fields) and spanning $0.2<z<2$. We convert the 7.7$\mu$m PAH luminosity to total IR luminosity, resulting in LFs that are two orders of magnitude fainter than previous studies. In contrast to previous extrapolations based on shallower observations, we find a strong flattening in the faint end of the LF with an average slope of $\alpha\sim0.147$. This indicates that less luminous galaxies do not have as much dust obscured star formation as predicted. We measure the star formation rate density (SFRD) by integrating our new IR LFs and find a slightly lower SFRD in all redshift bins than previous studies made with ALMA, Herschel, and Spitzer. We also measure the contribution to the SFRD as a function of luminosity and confirm that LIRGs and ULIRGs remain the dominant contributors to the dust-obscured star formation at $z\sim1-2$.
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All authors Bren E. Backhaus, Allison Kirkpatrick, Kurt Hamblin, Kaila Ronayne, Micaela B. Bagley, Steven L. Finkelstein, Dale D. Kocevski, Jeyhan S. Kartaltepe, Anton M. Koekemoer, Erini Lambrides, Casey Papovich, Gregory Troiani, Guang Yang

Instrumentation and Methods for Astrophysics

OpenGadget3 GPU solver tests

A. Ragagnin, G. S. Karademir, F. Groth et al. (+6 more)

We present an in-depth evaluation of the scalability and accuracy of the GPU porting of the N-body code for hydrodynamic cosmological simulations \og. While technical details of our GPU porting were presented in Ragagnin et al. (2020), in this work we focus on assessing the accuracy of the ported modules: the short range gravity integrator, the different components of the hydrodynamic solver, and the conjugate gradient solver for thermal conduction. We ran several tests that gradually increase the number of physical modules included: a gravity-only cosmological simulation; a hydrodynamical shock tube test; a non-radiative zoom-in simulation of a galaxy cluster in a cosmological box; and a full-physics zoom-in simulation of a galaxy in a cosmological box. Comparing the results obtained with the GPU implementation to those from the classical CPU version, we find excellent agreement across all tests, with small differences on very small scales. For the individual physical modules, we find a GPU chip-to-chip speedup ranging from $\approx3-5$. For more complex cosmological and hydrodynamical setups, where a large number of physical processes and overheads contribute to the total workload, the observed total chip-to-chip speedup (with the same number of nodes and CPUs per node) is $\approx2-3$. We ran our tests on four different supercomputers: Leonardo Booster (CINECA), MareNostrum-V (BSC), SuperMUC-NG2 (LRZ), and the CIP cluster of the Faculty of Physics at the Ludwig-Maximilians-Universität (LMU).
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All authors A. Ragagnin, G. S. Karademir, F. Groth, K. Dolag, L. M. Böss, T. Castro, N. Hariharan, M. Aiello, L. Tornatore

Astrophysics of Galaxies

Decoupled Kinematics and Excitation in the Compton-thick AGN NGC 6552: Spatially Resolved KOOLS-IFU Observations

Kyuseok Oh, Yoshihiro Ueda, Kanta Fujiwara et al. (+7 more)

Hard X-ray selected Compton-thick AGNs provide a relatively obscuration-resistant census of accretion, but optical line diagnostics can be strongly shaped by extinction and geometry. Spatially resolved integral-field spectroscopy can mitigate these effects and provides direct constraints on outflow kinematics and ionization state on kiloparsec scales. We present KOOLS-IFU optical integral-field spectroscopy of NGC 6552 obtained on the 3.8 m Seimei Telescope. Using spatially resolved emission-line ratios and non-parametric [O III]5007 kinematics over the central ~2 kpc, we test whether ionized-gas kinematics are locally coupled to excitation. The [O III]5007 width W80 is broadly elevated across the inner region (~530-830 km/s) and declines monotonically with projected galactocentric distance, consistent with a centrally concentrated outflow that decelerates at larger radii. Despite this clear kinematic structure, neither W80 nor the velocity asymmetry parameter dv shows a statistically significant correlation with [O III]5007/Hbeta. Order-of-magnitude outflow energetics yield Edot_K/L_bol ~ 0.01%-0.28% (for assumed n_e = 50-1000 cm^-3), consistent with [O III]-based estimates tracing only the ionized phase of a multi-phase outflow. We conclude that in NGC 6552 both the total line broadening traced by W80 and dv are consistent with being governed primarily by spatial dynamical structure and line-of-sight superposition of multiple kinematic components, with no statistically significant coupling to excitation-driven processes detected at our sensitivity level. A positive W80-[O III]5007/Hbeta coupling does emerge in the small subset of bins for which the two-component fit is most strongly favored statistically, which deeper observations will be needed to confirm.
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All authors Kyuseok Oh, Yoshihiro Ueda, Kanta Fujiwara, Keisuke Isogai, Satoshi Yamada, Keito Shimoda, Yoshiki Toba, Kazuya Matsubayashi, Shoji Ogawa, Yuya Nakatani

Earth and Planetary Astrophysics

The Effect of Adiabatic Index on Radius Evolution and the Mass Loss

Arick Collander and Eve J. Lee

Models that track the size evolution of exoplanets often assume a prescribed initial thermal state or a single adiabatic index to describe the planetary interior structure, the latter of which is taken to be $\gamma \sim1.4$ which is likely appropriate for evolved planets ($\gtrsim$1 Gyr). Extrapolating this high $\gamma$ to earlier ages (down to $\sim$million years old) is problematic since, according to thermodynamics, the adiabatic index of young planets is $\sim$1.2, which is low enough to drastically change how interior mass is distributed. We quantify the effect of varying the adiabatic index from 1.2 to 1.4 on the expected radius of the exoplanet over time. We find that envelopes of larger adiabatic indices start puffier with all else equal and undergo faster radius contraction with accelerated mass loss. Assumption of high $\gamma$ can therefore overestimate the effect of mass loss in shaping the exoplanetary population, especially when young planets are considered. We highlight the need for a more careful consideration of the initial thermal condition of planets in evolutionary models to properly interpret the radii measurements of exoplanets.
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Cosmology and Nongalactic Astrophysics

Hawai`i Supernova Flows: Bulk Flow Measurements using SNe Ia in the Optical and NIR

Aaron Do, Kaisey S. Mandel, Benjamin J. Shappee et al. (+9 more)

The present day peculiar velocity-field was sourced by primordial density fluctuations and sculpted over the lifespan of the Universe. Cosmological models such as $\Lambda$CDM make predictions for various statistical properties of peculiar velocities. Bulk flow, the average velocity within a given volume, has an expectation value of $\vec{0}$ due to isotropy, and a variance directly tied to the Hubble constant, the growth-rate of structure, and the matter power spectrum. In this paper, we use the redshifts and optical and near-infrared distance estimates to Type Ia Supernovae (SNe Ia) within subsets of the Hawai`i Supernova Flows dataset to infer the bulk flow within $z \lesssim 0.1$. The inferred speeds vary between ~100 to 400 km/s but are all consistent with the predictions of $\Lambda$CDM. As a secondary focus, we discuss the systematic uncertainty introduced by the discrete choice of methodology using two bulk flow estimators, two types of SN Ia distance estimators, and data covering two distinct regimes in wavelength space.
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All authors Aaron Do, Kaisey S. Mandel, Benjamin J. Shappee, R. Brent Tully, John L. Tonry, David Rubin, David O. Jones, Mitchell Dixon, Thomas de Jaeger, Dan Scolnic, Erik R. Peterson, Christopher R. Burns

Astrophysics of Galaxies

Chemical enrichment of the Perseus cluster core seen by XRISM/Resolve

XRISM Collaboration: Marc Audard, Hisamitsu Awaki, Ralf Ballhausen et al. (+142 more)

The intracluster medium (ICM) is rich in chemical elements, produced by core-collapse (SNcc) and Type Ia supernovae (SNIa) over the last $\sim$12 Gyr. Whereas cluster outskirts are uniformly enriched with Fe at $\sim$0.3 solar - strongly suggesting that the gas had been pre-enriched during or before the assembly of galaxies into clusters, the Fe abundance is known to centrally increase in the core of relaxed clusters. The origin of these central Fe peaks however, as well as the apparent presence of mysterious drops previously reported in the very centre of a number of systems, remain to be clarified. In this paper, we address these two questions by measuring the spatial distribution of Fe and its relative Si/Fe, S/Fe, Ar/Fe, Ca/Fe, Cr/Fe, Mn/Fe, and Ni/Fe ratios in the X-ray bright, nearby Perseus cluster. We take advantage of the unprecedented spectral resolution ($\sim$5 eV) offered by the Resolve microcalorimeter on board XRISM, which observed four distinct pointings of Perseus out to $\sim$250 kpc ($\sim$0.2$r_{500}$) during its Performance Verification phase. Although the presence of an X-ray bright AGN challenges a precise quantification of absolute abundances in the very core, our baseline analysis rules out a strong drop with $>$2$\sigma$ confidence, at variance with previous CCD measurements. In addition, we find a remarkable spatial uniformity of X/Fe ratios, supporting the idea of negligible late SNIa enrichment from the brightest cluster galaxy NGC 1275. We also compare the overall chemical composition of the Perseus ICM with SNcc and SNIa nucleosynthesis yield models, finding that the co-existence of two separate SNIa enrichment channels is not needed to reproduce the ICM ratios satisfactorily.
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All authors XRISM Collaboration: Marc Audard, Hisamitsu Awaki, Ralf Ballhausen, Aya Bamba, Ehud Behar, Rozenn Boissay-Malaquin, Laura Brenneman, Gregory V. Brown, Lia Corrales, Elisa Costantini, Renata Cumbee, Maria Diaz Trigo, Chris Done, Tadayasu Dotani, Ken Ebisawa, Megan E. Eckart, Dominique Eckert, Satoshi Eguchi, Teruaki Enoto, Yuichiro Ezoe, Adam Foster, Ryuichi Fujimoto, Yutaka Fujita, Yasushi Fukazawa, Kotaro Fukushima, Akihiro Furuzawa, Luigi Gallo, Javier A. García, Liyi Gu, Matteo Guainazzi, Kouichi Hagino, Kenji Hamaguchi, Isamu Hatsukade, Katsuhiro Hayashi, Takayuki Hayashi, Natalie Hell, Edmund Hodges-Kluck, Ann Hornschemeier, Yuto Ichinohe, Daiki Ishi, Manabu Ishida, Kumi Ishikawa, Yoshitaka Ishisaki, Jelle Kaastra, Timothy Kallman, Erin Kara, Satoru Katsuda, Yoshiaki Kanemaru, Richard Kelley, Caroline Kilbourne, Shunji Kitamoto, Shogo Kobayashi, Takayoshi Kohmura, Aya Kubota, Maurice Leutenegger, Michael Loewenstein, Yoshitomo Maeda, Maxim Markevitch, Hironori Matsumoto, Kyoko Matsushita, Dan McCammon, Brian McNamara, François Mernier, Eric D. Miller, Jon M. Miller, Ikuyuki Mitsuishi, Misaki Mizumoto, Tsunefumi Mizuno, Koji Mori, Koji Mukai, Hiroshi Murakami, Richard Mushotzky, Hiroshi Nakajima, Kazuhiro Nakazawa, Jan-Uwe Ness, Kumiko Nobukawa, Masayoshi Nobukawa, Hirofumi Noda, Hirokazu Odaka, Shoji Ogawa, Anna Ogorzałek, Takashi Okajima, Naomi Ota, Stephane Paltani, Robert Petre, Paul Plucinsky, Frederick S. Porter, Katja Pottschmidt, Kosuke Sato, Toshiki Sato, Makoto Sawada, Hiromi Seta, Megumi Shidatsu, Aurora Simionescu, Randall Smith, Hiromasa Suzuki, Andrew Szymkowiak, Hiromitsu Takahashi, Mai Takeo, Toru Tamagawa, Keisuke Tamura, Takaaki Tanaka, Atsushi Tanimoto, Makoto Tashiro, Yukikatsu Terada, Yuichi Terashima, Yohko Tsuboi, Masahiro Tsujimoto, Hiroshi Tsunemi, Takeshi Tsuru, Ayşegül Tümer, Hiroyuki Uchida, Nagomi Uchida, Yuusuke Uchida, Hideki Uchiyama, Shutaro Ueda, Yoshihiro Ueda, Shinichiro Uno, Jacco Vink, Shin Watanabe, Brian J. Williams, Satoshi Yamada, Shinya Yamada, Hiroya Yamaguchi, Kazutaka Yamaoka, Noriko Yamasaki, Makoto Yamauchi, Shigeo Yamauchi, Tahir Yaqoob, Tomokage Yoneyama, Tessei Yoshida, Mihoko Yukita, Irina Zhuravleva, Elena Bellomi, Ian Drury, Annie Heinrich, Julie Hlavacek-Larrondo, Julian Meunier, Konstantinos Migkas, Lior Shefler, Phillip C. Stancil, Nhut Truong, Benjamin Vigneron, Congyao Zhang, John ZuHone

Quantum Physics

Projected logical ensembles in surface codes via the random-matrix theory of quantum dots

Mircea Bejan, Jan Behrends, Max McGinley et al. (+1 more)

Measurements underpin active quantum error correction (QEC) and have been recognized as a source of novel measurement-induced many-body phenomena. Here, we study the statistical properties of post-measurement logical states arising in QEC on topological codes subject to deterministic transversal unitary gates. Upon syndrome extraction followed by maximum-likelihood decoding, a Born-weighted ensemble arises which we dub the "projected logical ensemble" (PLE). Focusing on surface codes subject to uniform single-qubit Pauli-$X$ rotations, we characterize the measurement-induced randomness of the PLE. To this end, we show that for a code with a single logical qubit, the PLE is isomorphic to an ensemble of scattering matrices describing mesoscopic quantum dots obtained from a 2D Majorana network model with suitable boundary conditions. We uncover regimes where these quantum dots are chaotic such that their scattering matrices are well-described by random matrix theory. In these regimes, the PLE approaches a universal ensemble that is maximally random up to symmetry and decoder-induced constraints. The symmetry constraints, set by stabilizer and logical operator weights, realize Altland-Zirnbauer classes D or DIII, which we both illustrate. Our results establish a fundamental connection between emergent universality concepts in mesoscopic physics, quantum many-body systems, and QEC.
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All authors Mircea Bejan, Jan Behrends, Max McGinley, Benjamin Béri

High Energy Physics (Theory)

Planck mass gravitinos in Einstein-Maxwell backgrounds

Artur Krawczyk, Krzysztof A. Meissner, Hermann Nicolai et al. (+1 more)

Charged massive spin-3/2 fields have long been regarded as problematic, because their coupling to electromagnetism generically leads to loss of hyperbolicity, acausal propagation and loss of unitarity. At the same time, fractionally charged supermassive gravitinos play a central role in a recent proposal of two of the present authors, where they are the only fermionic degrees of freedom beyond the Standard Model and provide novel dark matter candidates. We address this apparent tension by revisiting the result of Deser and Waldron, who showed that the inclusion of gravity can compensate the electromagnetic source of the inconsistency. For a minimally coupled Rarita-Schwinger field in an Einstein-Maxwell background, consistency requires a lower bound on the mass in terms of the charge and the cosmological constant. What is usually a severe obstruction to low-energy charged spin-3/2 phenomenology becomes an independent indication that such particles must lie close to the Planck scale, as argued by two of the present authors on other grounds. We rederive the inequality from the solvability of the Rarita-Schwinger constraints and from the characteristic determinant, emphasizing how the Einstein-Maxwell stress tensor compensates the purely electromagnetic pathology. We then reformulate the system using a Stückelberg spinor, showing that the helicity-1/2 sector reproduces the same condition. This formulation is also essential for obtaining a renormalizable propagator. We discuss this propagator and the corresponding ghost system.
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All authors Artur Krawczyk, Krzysztof A. Meissner, Hermann Nicolai, Bartłomiej Sikorski

High Energy Physics (Phenomenology)

$|V_{cb}|$ determinations from $\bar{B} \to D^{(*)} \ell \bar\nu$ decays within the SM and beyond

Wen-Sheng Fang, Syuhei Iguro, Xin-Qiang Li et al. (+3 more)

We investigate the $|V_{cb}|$ determinations from exclusive semi-leptonic $\bar{B} \to D^{(*)}\ell\bar\nu$ decays, together with comprehensive Bayesian fit analyses of the $\bar{B} \to D^{(*)}$ transition form-factors, by taking into account recent updates of experimental distribution data and theoretical evaluations. Several commonly adopted form-factor parameterizations, including BSZ, BGL and HQET, have been considered under different fit scenarios. We compare the fitted values and study how the $|V_{cb}|$ determinations depend on the form-factor parameterizations and on the treatment of the experimental inputs. Following the fit setup adopted by the PDG, we find that the BSZ, BGL, and HQET results are mutually consistent at specific truncation orders of the form-factor parameterizations. Our representative determinations are $|V_{cb}|=(39.3\pm0.3)\times10^{-3}$ for BGL $(N_F=2)$ and $(39.5\pm0.3)\times10^{-3}$ for HQET $(3/2/1)$, compatible with the official PDG average. We also consider new-physics effects that can contribute to $\bar{B} \to D^{(*)}\ell\bar\nu$. The allowed regions remain compatible with vanishing new-physics Wilson coefficients at the $95\%$ confidence level, and the improvements in agreement with the data are modest. The exclusive-inclusive $|V_{cb}|$ puzzle remains unresolved in the present analysis.
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All authors Wen-Sheng Fang, Syuhei Iguro, Xin-Qiang Li, Ria Sain, Ryoutaro Watanabe, Ben-Liang Zhang

General Relativity and Quantum Cosmology

Improving low-latency multi-messenger follow-up of neutron star-black hole mergers with mode-by-mode filtering

Francesco Iacovelli, Digvijay Wadekar, Javier Roulet et al. (+2 more)

Rapid parameter estimation for neutron star-black hole (NSBH) mergers is essential for deciding whether, where, and how electromagnetic facilities should follow up gravitational-wave alerts. Current low-latency analyses typically use only the dominant quadrupole harmonic, leaving strong degeneracies among luminosity distance, inclination, and intrinsic binary parameters. We show that mode-by-mode filtering of the $(2,2)$, $(3,3)$, and $(4,4)$ signal-to-noise-ratio (SNR) time series enables low-latency marginalization over higher-order-mode information at a computational cost comparable to quadrupole-only analyses. Applied to simulated NSBH detections in a LIGO-Virgo network at design sensitivity, our method improves constraints on luminosity distance, viewing angle, localization volume, and source-frame secondary mass, thereby sharpening crucial estimates of electromagnetic detectability and host-galaxy association. We also validate the approach on public data for previously detected NSBH events, finding the largest improvement for the asymmetric, higher-SNR event GW190814.
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All authors Francesco Iacovelli, Digvijay Wadekar, Javier Roulet, Emanuele Berti, Alessandra Corsi

Instrumentation and Methods for Astrophysics

The Lazuli Space Observatory: Opportunities for time-domain and multi-messenger astronomy

T. Wevers, T.J. Maccarone, A. Palmese et al. (+14 more)

Advancing time-domain and multi-messenger astronomy requires a multi-wavelength network of observatories capable of rapidly discovering, classifying, and characterizing transient phenomena. A critical gap in current capabilities is the inability to follow up faint, fast-evolving transients with sensitive, wide-band imaging and spectroscopic observations from space on timescales of minutes to hours. We discuss how the Lazuli Space Observatory will address this gap through a large collecting area, optical/NIR photometry and low-resolution integral field spectroscopy, and a rapid-response architecture with a mission requirement of $<$4 hours from trigger to first photon. Based on a latency analysis, we find a credible path to realizing response times well below this requirement, with best-case scenarios below 90 minutes under favorable conditions. We highlight extragalactic science opportunities in currently un(der)explored parts of parameter space, including gravitational wave follow-up, kilonova characterization, supernova progenitor physics, and a wide variety of fast-evolving transients and high redshift events. We further outline new observational capabilities for Galactic time-domain science, including high frequency variability in accreting systems, precision astrometry of compact objects, and the detection of compact and ultracompact binaries, enabled by high-frequency, diffraction-limited imaging and astrometry. Together, its capabilities - combining flagship sensitivity with response times one to two orders of magnitude faster than existing large space observatories - position Lazuli to make transformative contributions across time-domain and multi-messenger astrophysics.
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All authors T. Wevers, T.J. Maccarone, A. Palmese, D.J. Sand, S. Gezari, L. Rivera Sandoval, J. DiPalma, G. Hosseinzadeh, T.J. Hoyt, M. Karmen, J. Kennea, K. Kunnumkai, S. Perlmutter, M. Rigault, A. Roy, G. Stefansson, F. Yang Yang

General Relativity and Quantum Cosmology

Quantum fate of the Choptuik naked singularity

Chih-Hung Wu

Classical critical collapse provides a dynamical route from smooth initial data to a naked singularity, representing a sharper violation of predictability than ordinary black hole singularities. We argue that this distinction is erased by quantum backreaction. Building on the semiclassical interior analysis, where quantum self-energy of the collapsing matter generates a universal growing mode and a finite mass gap, we study the exterior naked singularity region that determines global visibility in the Einstein-scalar system. We analyze controlled exterior models in both $2+1$ and $3+1$ dimensions. In the former, smooth matching and physical boundary conditions analytically select a vacuum polarization state, whose backreaction cloaks the classically naked region by a quantum trapped branch. In the latter, numerical horizon tracing shows that near a quantum-shifted threshold the exterior develops finite-mass marginally trapped surfaces rather than a zero-mass naked endpoint. These results suggest a global quantum picture in which the Choptuik naked singularity shares the fate of an ordinary black hole singularity: quantum effects push the putative Cauchy horizon behind a quantum-generated horizon, thereby reducing the loss of predictability to the standard black hole evaporation problem.
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High Energy Physics (Phenomenology)

PineAPPLv1: fast and flexible theory predictions for present and future colliders

Tomáš Ježo, Emanuele R. Nocera, Tanjona R. Rabemananjara et al. (+3 more)

We present PineAPPLv1, a library designed to provide accurate and flexible interpolation tables of partonic cross sections that can be convolved with parton distribution functions (PDFs) and fragmentation functions (FFs) for the fast evaluation of high-energy physical observables. The core feature of the new release is the support of multiple convolutions involving initial- and final-state hadronic particles, with any polarisation, that are associated with PDFs and FFs. The library simultaneously supports polarised and unpolarised distributions that obey space-like or time-like evolution, and is developed for an arbitrary number of them, even if physical processes typically only require a few. Control of scale choices when more than one scale characterises a scattering process is also possible. We describe the technical details of the new representation of interpolation coefficients stored in the grid, and we demonstrate the capabilities of the library in a few phenomenological cases of interest. Specifically, we compute predictions for single-inclusive pion production in unpolarised and polarised proton-proton collisions and in semi-inclusive deep-inelastic scattering. We show how, in each case, PDF, FF, and scale uncertainties compare to each other and highlight the potential of PineAPPL as an essential ingredient for precision physics at current and future colliders.
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All authors Tomáš Ježo, Emanuele R. Nocera, Tanjona R. Rabemananjara, Christopher Schwan, Tanishq Sharma, Jan Wissmann

High Energy Physics (Phenomenology)

Short-Range Correlations Between Partons in a Proton

Jen-Chieh Peng, Krishna Rajagopal and John Terry

A principal lesson from recreating droplets of quark-gluon plasma (QGP) in heavy ion collisions is that it is a strongly coupled liquid, not a plasma of partons. The energy density and pressure of quarks and gluons confined within a proton are comparable to those of QGP at or just above the QCD transition temperature. Given this similarity between protons and QGP, we propose that the investigation of correlations between nearby partons within a proton must be a central goal for the future Electron-Ion Collider (EIC). Here, we ask how EIC measurements can discern such short-range correlations (SRCs) of quark pairs. Doing so would characterize the strongly coupled interior of a proton, augmenting the one-parton-at-a-time understanding of protons via (generalized) parton distribution functions, and could at the same time yield a key ingredient for the microscopic understanding of the liquid nature of QGP. Motivated by the experiments that have been used to demonstrate the existence of SRCs between nucleon pairs within a nucleus, we propose using EIC observables involving measurements of a jet and a pion, together with the scattered electron, to seek and quantify the possible existence of SRCs between quark pairs within a nucleon. The pronounced isospin dependence observed in the dominance of $np$ SRCs over $pp$ or $nn$ SRCs has played a central role in establishing the importance of SRCs among nucleons in nuclei. Analogously, the QCD attraction in the $ud$ diquark channel can make the $ud$ SRC stronger than the $uu$ and $dd$ SRCs, allowing a first observation of partonic SRCs.
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High Energy Physics (Phenomenology)

Are neutrinos Majorana? Fixed-target and high-energy astrophysical searches decide

Gabriela Barenboim, Mauricio Bustamante and Qinrui Liu

The original version of this paper proposed a new approach to determining whether neutrinos are Dirac or Majorana fermions, a fundamental open question in particle physics. Conventional searches rely on neutrinoless double beta decay, but this electron-only channel suffers from blind spots. We propose a new, complementary probe to overcome this limitation. A heavy neutral lepton (HNL) triggers a high-energy shift in how the active neutrino flavors ($\nu_e$, $\nu_\mu$, $\nu_\tau$) mix—but only if the neutrinos are Majorana. For GeV-scale HNLs, the upcoming beam-dump experiment SHiP can discover the HNL and measure how it mixes with the active flavors. However, the proposed signature of the Majorana nature of neutrinos does not exist. The reasons are explained here. The analysis has been superseded by Ref.~\cite{Barenboim:2026udr}. The original version is retained as v1 for the record.
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Astrophysics of Galaxies

The flaring drill in the Galactic centre. Did the IRS 13 cluster carve out the mini-cavity in the mini-spiral?

Jaroslav Haas, Pavel Kroupa, Florian Peißker et al. (+1 more)

The mini-cavity is a low-density region observed in the complex of streams of ionized gas around the Galactic central supermassive black hole, Sgr A$^\star$, known as the mini-spiral. Its near-circular shape is suggestive of a formation due to the effect of stellar winds. No suitable stars are currently observed within the mini-cavity, however. In this study we assessed whether the mini-cavity could have been formed by the winds of the stars from the neighbouring IRS 13 cluster that were located at the position of the mini-cavity in the past but moved away from it later on owing to their orbital motions around Sgr A$^\star$. Furthermore, we estimated the rate of accretion of the then-abundant interstellar medium onto the putative intermediate-mass black hole that has been proposed to reside in the IRS 13 cluster and the corresponding X-ray luminosity of this black hole. The estimates were obtained analytically using the astrophysical properties reported for the involved objects and the environment. Based on our results, we suggest that the mini-cavity was formed by the winds of the IRS 13 cluster member stars about 300 years ago, when this cluster went through the Bar region of the mini-spiral. The accompanying accretion of the interstellar medium onto the putative intermediate-mass black hole in this cluster may have produced multiple X-ray flares with luminosities of $\approx10^{39}$ erg/s. Such flares are compatible with the X-ray reflections currently observed on the molecular clouds in the complexes Sgr A, B, and C, including the necessary light-travel time delay.
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All authors Jaroslav Haas, Pavel Kroupa, Florian Peißker, Mark R. Morris

Solar and Stellar Astrophysics

On the Robustness of Bi-Stability Jump Predictions

Jorick S. Vink, Gautham N. Sabhahit and Andreas A. C. Sander

The bi-stability jump is a long-standing theoretical prediction of radiatively driven wind theory, associated with Fe IV/III recombination around T = 21000 - 25000 K. While most theoretical approaches predict a strong increase in mass-loss rates across the bi-stability jump, most empirical mass-loss studies of OB supergiants have not revealed the expected signature. We computed new hydro-dynamically consistent PoWR models at low and intermediate Eddington parameters to test whether the bi-stability jump persists in the canonical B supergiant regime. The PoWR models presented here predict a robust bi-stability jump, with an increase in mass-loss rate by more than an order of magnitude and a simultaneous drop in terminal wind velocity in line with Monte Carlo models and other co moving frame (CMF) calculations. The jump coincides with a transition in the dominant line driver from Fe IV to Fe III. The presence of the bi-stability jump is not restricted to high Gammae objects and remains present for models well below the LBV/hypergiant regime. The persistence of the bi-stability jump in hydro-dynamically consistent models at lower Gammae supports the interpretation of the bi-stability jump as a temperature-driven ionisation effect that operates once a stationary line-driven wind solution exists. The continuing discrepancy between predictions and empirical population studies motivates further code comparison work and controlled observational tests using individual objects such as LBVs.
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High Energy Astrophysical Phenomena

Constraints on Late-Time Flaring from Luminous Fast Blue Optical Transients using the Transiting Exoplanet Survey Satellite and the Zwicky Transient Facility

Rahul Jayaraman, Anna Y. Q. Ho, Michael M. Fausnaugh et al. (+14 more)

The Luminous Fast Blue Optical Transient (LFBOT) AT2022tsd exhibited minutes-timescale optical flares in the tens of days following the initial transient event, likely due to a central engine – either an accreting black hole or a magnetar. In this paper, we use data from the Transiting Exoplanet Survey Satellite (TESS) and the Zwicky Transient Facility (ZTF) to constrain the occurrence of similar flares in the 12 (of 14) known LFBOTs that had observational coverage with TESS from tens of days to thousands of days after the transient's initial emission. We find seven flare-like signals at the locations of four unique LFBOTs; all seven can likely be attributed to a solar system object (SSO) moving through the TESS aperture. Assuming all seven flares arise from SSOs, for the LFBOT AT2024qfm we rule out flaring with a similar timescale (40–65 d) and luminosity ($\nu L_\nu\sim10^{43}$ erg s$^{-1}$) as in AT2022tsd, while for AT2022tsd itself we rule out flares between 380–430 d after the initial transient that were as luminous as the earlier flares. This observation suggests that the engine power in AT2022tsd declined or shut off on a timescale of hundreds of days. We also find that there is no late-time activity detectable in TESS thousands of days after the prototype LFBOT, AT2018cow. We discuss our constraints on the duty cycle of such flaring and then present estimates for the number of minutes-duration flares detectable with ongoing and upcoming high-cadence ($\ll1$ d) wide-field surveys.
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All authors Rahul Jayaraman, Anna Y. Q. Ho, Michael M. Fausnaugh, Eran Ofek, Daniel A. Perley, Ruslan Konno, Martti Kristiansen, Tracy X. Chen, Michael W. Coughlin, Steven L. Groom, George Helou, K.-Ryan Hinds, Mansi M. Kasliwal, Zoë McGrath, Josiah N. Purdum, Argyro Sasli, Jesper Sollerman

Materials Science

Chiral Phonons Enable Ultrafast Magnetization Switching via Magnetoelastic Coupling

Weiwei He, Muhammad Hamza Asim, Mara Strungaru et al. (+3 more)

Phonons are desirable for current-free energy-efficient spin manipulation and harnessing their chirality to achieve ultrafast magnetization switching remains actively pursued. Here we demonstrate that terahertz-driven chiral phonons enable faster magnetization switching than linear phonons through the purely magnetoelastic coupling that transfers both energy and angular momentum. Only one phonon handedness efficiently transfers angular momentum to the spin system, which we explain by a large fictitious kinematic Barnett-like field at THz frequencies that destabilizes spin precession for the opposite chirality. Considering different regions of the spinwave spectrum, we find that switching conditions can be realized near the {\Gamma}-point where strong energy transfer and spinwave excitation dominate, and near the P-point which offers minimal energy loss. Our results establish phonon chirality as a decisive and previously overlooked parameter in spin-lattice dynamics within the magnetoelastic coupling mechanism, offering a promising avenue for ultrafast low-energy spintronic devices.
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All authors Weiwei He, Muhammad Hamza Asim, Mara Strungaru, Roy Chantrel, Min Yi, Oksana Chubykalo-Fesenko

Fluid Dynamics · Cross-listed from stat.AP

Regularized Machine Learning for System Identification of Ship Free-Running Manoeuvres from CFD-Based Synthetic Data: A Comparative Study

R.F. Suárez, J.C. Berndt and M. Abdel-Maksoud

This study investigates supervised machine learning techniques for identifying ship hydrodynamic coefficients from CFD-generated data from free-running simulations. Specifically, ordinary least squares and regularized regression methods are applied to Abkowitz-type manoeuvring models. Training and validation datasets are derived from URANS simulations of zig-zag and turning circle manoeuvres, which are validated against experimental benchmark data. The analysis evaluates the effects of coefficient set size, minimum training length required for predictive model training, and manoeuvre combinations on model performance. Results demonstrate the suitability of large-angle zig-zag manoeuvres for hydrodynamic system identification, provided that multicollinearity is addressed through appropriate coefficient selection, regression models, or input data variability. Larger coefficient sets offer greater model flexibility for variable conditions but are more prone to multicollinearity. Regularized regression techniques effectively mitigate multicollinearity and notably enhance prediction accuracy, as does incorporating more diverse manoeuvring data. Among tested models, Ridge regression provided the best compromise between computational efficiency and prediction accuracy.
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Chemical Physics · Cross-listed from cs.LG

Noise-Driven Escape from Metastable Phases explains Grokking in Deep Neural Networks

Ibrahim Talha Ersoy and Karoline Wiesner

Deep neural networks (DNNs) exhibit first order phase transitions under variations of the L2 regularization strength, with each transition marking the onset of a new learnable feature. Below a critical regularization strength, all features are in principle learnable, but coexisting metastable states, separated by energy barriers, can trap the network and impede convergence. A strength of DNNs is their ability to generalize. But many open questions remain, among them the origin of so called grokking: the abrupt, delayed onset of generalization after prolonged apparent overfitting. We show for linear DNNs that grokking is consistent with hysteresis in first-order L2 phase transitions: using L2 regularization to engineer deliberate trapping, we demonstrate that a model in a low-accuracy metastable state escapes only when SGD noise drives it across an energy barrier, with escape times following Arrhenius scaling. We reproduce grokking-like delayed convergence across two orders of magnitude in escape time by deliberately trapping models in metastable phases. Using sparse sub-sampling we also reproduce the canonical grokking curve where test error eventually approaches the final training error. Our work suggests that the number of metastable states equals the number of learnable features – one per singular value of the data covariance – the potential for hysteresis grows naturally with task complexity. We provide evidence that the same mechanism likely operates in general nonlinear DNNs. Our results provide routes toward more efficient learning schemes.
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Earth and Planetary Astrophysics

Simultaneous Tricolor Video Observations of Three Tiny Near-Earth Asteroids with Sub-Minute Rotation Periods

Jin Beniyama, Ryou Ohsawa, Shigeyuki Sako et al. (+4 more)

Studying the physical properties of near-Earth asteroids (NEAs) is crucial for understanding their dynamical histories and origins, and assessing impact hazards to Earth. Tiny NEAs with diameters smaller than 100 m are intrinsically faint and are typically observable only during close approaches, resulting in few well-characterized objects. Furthermore, because these objects are often fast-moving and fast-rotating, sequential multiband photometry is prone to systematic offsets in derived colors. To mitigate this effect, we performed simultaneous $g$-, $r$-, and $i$-band photometry of three tiny NEAs using the TriColor CMOS Camera and Spectrograph (TriCCS) on the 3.8 m Seimei Telescope. We used high-cadence video observations with exposure times of 1 s and 5 s to investigate lightcurve variations on timescales of seconds. All three NEAs are confirmed as fast rotators with rotation periods shorter than 60 s: $15.281\pm0.002$ s for 2021 TY$_{14}$, $21.099\pm0.003$ s for 2021 UW$_{1}$, and $8.779\pm0.013$ s for 2022 GQ$_{1}$. The derived colors indicate that 2021 TY$_{14}$ belongs to the X-complex, while 2021 UW$_{1}$ and 2022 GQ$_{1}$ belong to the S-complex. Their positions in the diameter–rotation period diagram show that all three objects belong to the small, fast-rotating NEA population, with 2022 GQ$_{1}$ being the smallest and fastest-rotating among them with spectroscopic measurements. Analysis of the color time series suggests that the surfaces of observed NEAs are largely homogeneous, although 2021 TY$_{14}$ exhibits statistically significant $g-r$ color heterogeneity with a projected spot fraction of approximately 50%. For 2021 UW$_{1}$, minor localized variations of up to $\sim20$% in composition cannot be ruled out.
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All authors Jin Beniyama, Ryou Ohsawa, Shigeyuki Sako, Satoshi Takita, Daisuke Kuroda, Tomohiko Sekiguchi, Keisuke Isogai

Strongly Correlated Electrons

Compact Spin-Charge Separated Neural Quantum States for Valence-Bond States

Ang-Kun Wu, Louis Primeau, Yixin Zhang et al. (+3 more)

Neural-network quantum states (NQS) provide a flexible nonlinear representation of quantum many-body wavefunctions, but their efficiency depends sensitively on whether the architecture reflects the sign structure and constrained Hilbert space of the target state. In this work, we propose a solvable-point-guided strategy: design the architecture at an exactly solvable point where the correct local rules can be read off, then refine to the non-exact regime by enlarging only the kernel size and hidden dimension. The strategy is built from four physics-motivated designs: a stride-matched local-rule convolution, geometric pooling, a sign-resolving $\tanh(x^{2k+1})$ activation, and explicit spin-hole sector separation. We test this approach on quasi-one-dimensional valence-bond-solid (VBS) states and their doped soliton variants (sVBS), the exact ground states of a $t$-$J$-like model with a single mobile hole. In finite-size benchmarks, this architecture reaches high fidelity for the exact sVBS state with substantially fewer parameters than generic fully connected, convolutional, and transformer baselines tested under the same setup. For the spin sector, the learned local rule transfers from small to larger systems without retraining. Away from the solvable point, increasing kernel size and hidden dimension systematically improves accuracy, and the model shows approximately $L^2$ parameter scaling in the gapless regime for system size $L$, compared with approximately $L^4$ for matrix-product states in the same regime. Our work establishes a recipe for compact NQS in sign-structured, constrained Hilbert spaces and paves the pathway to physics-informed architectures for the broader $t$-$J$ and Hubbard families.
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All authors Ang-Kun Wu, Louis Primeau, Yixin Zhang, Jingtao Zhang, Adrian Del Maestro, Yang Zhang

High Energy Astrophysical Phenomena

Fermi-eROSITA cross-correlations suggest annihilation lines of $\sim70$ GeV WIMPs

Uri Keshet

The deep potential wells of galaxy clusters provide some of the strongest constraints on the velocity-dependent ($p$-wave) annihilation of weakly interacting massive particle (WIMP) dark matter. Cross-correlating high-latitude Fermi-LAT 16.3-year data with the western Galactic hemisphere eROSITA map facilitates high-sensitivity tests. A blind composite matched-filter scan of the cross-correlated spectrum for the $\chi\chi\to\gamma\gamma$, $\gamma Z$, and $\gamma h$ annihilation-line triad of a single WIMP $\chi$ finds $m_\chi c^2\simeq71.9$ and $67.5$ GeV triads, each with a local $Z$-score $\sim3$ and a (henceforth global) $1.6\sigma$ (trial-corrected by pixel shuffles; $1.8$-$2.1\sigma$ in Monte Carlo and analytic estimates), insensitive to details of detrending, sky masks, and filters. Scanning for the line nonad of two cross-annihilating WIMPs finds $66.4$ and $71.9$ GeV masses (with a weak $69.2$ GeV cross-annihilation triad) at $2.3\sigma$. The leading $\sim72$ GeV triad coincides with the mass implied by interpreting the recently reported $\sim43.2$ GeV $\gamma$-ray line in three nearby clusters as its $\gamma Z$ channel. At this externally fixed mass, the triad reaches $3.0\sigma$ alone, and $5.1\sigma$ when combined with the reported line ($3.9\sigma$ under alternative assumptions). The triad, absent from the ambient (X-ray-uncorrelated) spectrum, presents in different Galactic sectors, strengthens under cosmological (positive) but not negative redshift broadening $\Delta z$, and peaks at $\Delta z\simeq 0.05$, consistent with expectations; its two non-$43$ GeV channels reach $2.3\sigma$ by themselves. Measured (not loss-corrected) intrinsic cross sections are a few $10^{-19}$ cm$^3$ s$^{-1}$ for WIMPs tracing the X-ray gas.
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