Quantum Physics
An End-to-End Hybrid Quantum-Classical Sampling Workflow for Discrete Markov Random Fields: A Reproducible Case Study
Arul Rhik Mazumder and Elias Towe
Sampling from discrete Markov random fields (MRFs) is a hard problem. We study amplitude-encoded i.i.d. sampling for small MRFs where $2^n$ target probabilities are precomputed classically. This removes
quantum exponential speedup but allows a clean comparison against classical MCMC based on independent
circuit samples ($\tau \approx 1$). Across 60 instances spanning five graph families (1k-step burn-in, 3k retained samples), the mean ESS ratios of
Quantum to Single-Site Gibbs, Block Gibbs, Tuned-Block, and Parallel Tempering are $16.35$, $7.29$, $1.82$, and $1.79$, showing modern classical samplers substantially close this gap. Amortizing $O(2^n)$ preprocessing into wall-clock time, exact inverse-CDF sampling yields $17.7$M ESS/s versus $488$K ESS/s for the
quantum sampler ($36\times$ mean rate, $153\times$ per-instance), confirming no wall-clock advantage. We characterize MCMC autocorrelation costs and
benchmark amplitude-encoded state preparation at $n \in \{8,10,12\}$. An MPS scaling study ($n \le 40$) shows bond dimension $\chi=32$ achieves $F=0.721\pm0.059$ at $n=40$. Finally, a matched-budget VQC vs. MPS comparison at $n \in \{8,10,12\}$ shows VQC fidelities fall far below MPS: $(F_{\mathrm{VQC}}, F_{\mathrm{MPS}}) = (0.31, 0.99), (0.21, 0.96), (0.17, 0.88)$ at compressions $10.7\times$, $34.1\times$, and $113.8\times$.
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Quantum Physics
Benchmarking Zero-Setup Quantum Circuit Simulators
Arul Rhik Mazumder, Hovnatan Karapetyan, Mohammed Zuhair Mullath et al. (+3 more)
Practitioners increasingly rely on hosted simulation environments, but their performance characteristics remain poorly documented. We present a systematic benchmarking study of GPU-accelerated approximate
quantum simulation across two widely used methods:
matrix product states (MPS) and Pauli path simulation (PPS), comparing BlueQubit (a hosted tool that handles hardware provisioning, simulator configuration, and job orchestration) against AWS Braket,
Quantum Rings, Qiskit pauli-prop, and PauliPropagation (written in Julia). For MPS, we find that GPU runtime yields sub-quadratic scaling with bond dimension, with a growing advantage over CPU at increasing scale. For Pauli path simulation on IBM's 127-
qubit kicked Ising
benchmark, GPUs deliver up to ${\sim}1{,}700\times$ speedup at fine truncation thresholds ($\delta = 2.5 \times 10^{-5}$, 27.6M Pauli terms), and are the only backends that reach accuracy regimes below $\delta = 10^{-5}$, which remained inaccessible to the commodity CPU-based implementations and self-contained SDKs evaluated here. We also provide a reproducible characterization of these simulators across regimes, including tradeoffs that isolated evaluations do not show. All benchmarking code and configurations are in a public GitHub repository.
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All authors Arul Rhik Mazumder, Hovnatan Karapetyan, Mohammed Zuhair Mullath, Rudy H. Tanin, Hrant Gharibyan, Hayk Tepanyan
Materials Science
Approximate explicit formulas for Stoner-Wohlfarth hysteresis loops
Savin Vladimir P. and Koksharov Yury A
Approximate explicit formulas for the hysteresis loops in the Stoner-Wohlfarth model are derived. We consider the hysteresis loops both for a single particle with a fixed easy-axis direction and for an ensemble of particles with randomly oriented anisotropy axes. The physical assumption used to derive the formulas is that the particle
magnetic moment lies in the vicinity of the easy axis or the external field direction, at low and high fields, respectively. Surprisingly, the low-field formula is approximately valid even near the Stoner-Wohlfarth astroid, where the reduced
magnetic field h0 is not very small. The general piecewise formula is obtained by an appropriate matching of the functions defined on different intervals of the
magnetic field, which are chosen to maximize the formula accuracy. For the averaged hysteresis loop, the maximal, but reasonably small, deviation of our formula from numerically calculated magnetization occurs at h0 = 0.5, which corresponds to the sharp change in magnetization slope.
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High Energy Physics (Theory)
Anomaly cancellation for two $U(1)$ factors
Ben Gripaios and Khoi Le Nguyen Nguyen
We show that solving the abelian part of the local anomaly cancellation conditions for a 4-d gauge theory whose gauge Lie
algebra has an abelian summand with rank $K \geq 1$ is equivalent to the problem in algebraic/arithmetic geometry of finding $(K-1)$-dimensional projective linear subspaces of a cubic hypersurface over the rational numbers, where the cubic is determined by the data of the semisimple summand and the representation thereof carried by the Weyl
fermions. We then use this reformulation to solve a variety of examples with rank 2. The simplest non-trivial example from physics, namely gauge Lie group $U(1)^2$ and six
fermions, nevertheless has a rich (and well-studied) geometry: it corresponds to the Fano variety of lines in the Segre cubic primal threefold. This is a surface with 15 irreducible components that are planes (which correspond to lines lying in the 15 planes in the Segre cubic primal and which give rise to non-
chiral fermions) and 6 components that are split del Pezzo surfaces of degree 5 (which give rise to
chiral fermions). These components are all rational varieties, enabling all solutions to the anomaly cancellation conditions to be parametrized and their collective properties (e.g. their
topology and asymptotic distribution) to be described.
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General Relativity and Quantum Cosmology
Exceptional lines in the Kerr-Newman black hole spectrum
João Paulo Cavalcante and Maurício Richartz
We investigate massive scalar perturbations of Kerr-Newman black holes, focusing on the $(\ell,m) = (1,1)$ quasinormal mode spectrum in the near-extremal regime. We identify a sequence of exceptional lines, at which overtone frequencies become degenerate, together with a corresponding sequence of exceptional points for massless fields. We analyze the
geometric phases associated with these exceptional points by transporting the spectrum around closed loops in parameter space and examining the resulting permutation of quasinormal mode frequencies. We further show that these degeneracies are closely related to the branching of the spectrum into zero-damping and damped modes, and derive an analytic expression for the frequencies of the zero-damping modes in the extremal limit.
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Quantum Physics
Revealing Entanglement-Growth Mechanisms through the Magic Barrier
Lv Zhang, Shi-Xin Zhang, Heng Fan et al. (+1 more)
Quantum entanglement and magic are complementary resources underlying
quantum computational advantage, yet their dynamical relation in many-body systems remains poorly understood. In this Letter, we show that the mechanism of bipartite
entanglement growth is encoded in the relative timescale between the
entropy-growth-rate peak and the magic barrier, defined as the transient peak of the anti-flatness of the
entanglement spectrum. When
entanglement is locally built, the same microscopic process increases the
entropy and reshapes the Schmidt spectrum, so the magic-barrier peak occurs in the time window of maximal
entropy growth. When
entanglement is mainly transported or redistributed,
entropy can grow before appreciable spectral non-flatness is generated, naturally separating the two peak times. We demonstrate this distinction in the random-field XXZ chain: the two peaks remain strongly correlated in the thermal regime, while their separation grows systematically across the thermal–MBL crossover. We further validate this theoretical framework by employing Bell-pair initial states alongside a tunable SWAP–Haar random
circuit. Our results reveal an intrinsic dynamical connection between
entanglement and magic, establishing the magic barrier as a powerful spectral diagnostic of how
quantum information is generated, transported, and reshaped.
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All authors Lv Zhang, Shi-Xin Zhang, Heng Fan, Shuo Liu
Earth and Planetary Astrophysics
How Many Transiting Giant Planets Can JWST Search for Moons and Rotational Oblateness?
Le-Chris Wang and Joshua N. Winn
Observations with the James Webb Space
Telescope (JWST) can, in principle, detect moons and rotational oblateness of
giant exoplanets through subtle distortions of transit light curves. The most favorable
planets are expected to be on wide orbits ($\gtrsim$0.3~AU) where moons and rapid rotation are more likely to survive
tidal evolution. No unambiguous detections have yet been reported. Here, we forecast the number of systems with sufficiently favorable properties to allow for secure detections, using JWST noise models, analytic detectability scalings,
giant-
planet occurrence rates, and the
Gaia star catalog. For
planets orbiting 0.9–1.6$\,M_\odot$
stars and a noise model based on demonstrated JWST performance, single-transit observations should be capable of detecting Jupiter-like rotational oblateness in several known systems and of order 10 systems yet to be discovered, if obliquities are typically $\gtrsim$10$^\circ$. A similar number of systems are favorable for Ganymede-sized moons, if such moons are common. The yields can increase to tens or hundreds of systems if lower-mass host
stars are included or if JWST can achieve
photon-limited performance. Time-correlated noise on 1–10 hr timescales can strongly suppress these yields; a noise floor of a few tens of parts per million is enough to hide oblateness or moons in many otherwise favorable systems. Successful searches will therefore require both a more complete census of long-period transiting
giant planets and low levels of instrumental systematics and
stellar variability.
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High Energy Astrophysical Phenomena
The Radio Properties of Extreme Coronal Line Emitters: Constraints on the Sub-parsec Environment
Noah Franz, Kate D. Alexander, Collin T. Christy et al. (+10 more)
A tiny fraction ($\ll1\%$) of
galaxies display luminous, high-ionization metal emission lines, which may be persistent or variable. These extreme coronal lines (ECLs) are produced when soft X-ray
photons intercept dense gas ($n\gtrsim10^{6-7}~{\rm cm^{-3}}$). The high X-ray flux required implicates intense
nuclear activity, likely originating from
tidal disruption events (TDEs) and active
galactic nuclei (AGN). As ECLs are rarely seen even within these classes, their production may also require specific environmental conditions, but the details remain unclear (e.g., the geometry and volume filling factor of the ECL-producing gas). Here, we present the
radio properties of a population of $27$ low-
redshift ($z<0.3$) ECL emitting
galaxies (ECLEs), providing a unique and previously unexplored probe of the properties of the circumnuclear medium (CNM; $\lesssim1$ pc from the black hole) in these systems. We find that $\sim 50\%$ of ECLEs produce
radio synchrotron emission with luminosity and
evolution consistent with TDEs and/or AGN.
Radio spectral modeling of four ECLEs reveals that the ECL-producing region is (1) clumpy with a low volume filling factor ($10^{-5}\lesssim f_{V}\lesssim10^{-2}$) and (2) likely distinct from the
radio emitting region (implying, e.g., a clumpy toroidal geometry). For time-variable ECLEs, these are some of the first observational constraints on the CNM geometry in formerly quiescent
galactic nuclei. The unique nature of ECLEs makes them an excellent high-energy laboratory to connect the physics of
accretion, photoionization, and feedback in
galactic nuclei, thus motivating continued multi-wavelength monitoring.
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All authors Noah Franz, Kate D. Alexander, Collin T. Christy, Tanmoy Laskar, Stefanie Komossa, Enrico Ramirez-Ruiz, Jean Somalwar, Edo Berger, Ryan Chornock, Fabio De Colle, Gavin Farley, Megan Newsome, B. Ashley VanderLey
Instrumentation and Methods for Astrophysics
LISA 10 – Library and Information Services in Astronomy. Report on the ESO workshop
Leslie Kiefer, Uta Grothkopf, Silvia Meakins et al. (+1 more)
The 10th LISA conference (LISA 10) took place at ESO Chile in early November 2025. The theme, Research Equity and Access in the Age of AI, highlighted the rapidly evolving landscape of scholarly communication in astronomy. Artificial intelligence, open access mandates, and expanding data archives are transforming scientific practice and information in an increasingly interdisciplinary research environment. Through presentations, posters, and discussions, LISA 10 explored how these developments are redefining the management of astronomy information work and the role of librarians.
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All authors Leslie Kiefer, Uta Grothkopf, Silvia Meakins, Mahmut Eren
Instrumentation and Methods for Astrophysics
Neural Posterior Estimation for Inferring Weak Lensing Shear
Tim White, Dingrui Tao, Camille Avestruz et al. (+2 more)
The prevailing approach to inferring weak gravitational
lensing shear from images involves detecting
galaxies, estimating their ellipticities, and calibrating these estimates to correct for image noise, selection bias, and model misspecification. Characterizing the statistical model and assumptions underlying this pipeline is challenging, which makes it difficult to propagate uncertainty through its various stages. As an alternative, we propose to infer shear using neural posterior estimation (NPE), a type of simulation-based inference. We train a deep neural network to map a simulated multiband image to a variational distribution over the underlying shear field, thereby folding
galaxy detection, deblending, measurement, and calibration into a single implicit inference step. Once trained, the network accounts for all features present in the simulated images, including potential sources of bias. In experiments on simulated constant-shear images with increasingly complex observational effects, NPE produces accurate and well-calibrated posterior approximations for both shear components in the presence of blended
galaxies, spatially varying point spread functions,
stars, and detector artifacts. These results demonstrate that NPE can be a viable shear estimation method in settings where all anticipated features and artifacts can be simulated, a requirement that will become increasingly feasible as simulation fidelity improves in the coming decades.
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All authors Tim White, Dingrui Tao, Camille Avestruz, Jeffrey Regier, the LSST Dark Energy Science Collaboration
Astrophysics of Galaxies
Six-Class BPT Galaxy Classification for Survey-Scale AGN Candidate Prioritization: Deep Tabular Model and Informative Missingness Signals
Shanquan Gui
The Baldwin–Phillips–Terlevich (BPT) diagram is widely used to classify
galaxies into
star-forming systems, composite
galaxies, and active
galactic nuclei (AGNs), but its survey-scale application is limited by the requirement for high signal-to-noise emission-line measurements. We test whether machine-learning models can reproduce six-class BPT labels while using measured quantities, derived line ratios, and potentially informative missing-data patterns as inputs. We analyze 1.47 million
galaxies with a 27-dimensional feature set that combines raw survey measurements, derived quantities, and missingness indicators. Five deep tabular architectures are benchmarked against gradient-boosted trees and classical machine-learning baselines, and the resulting probabilities are evaluated through hard-classification metrics, precision–recall curves, top-$k$
retrieval, ablation tests, and feature-interpretation diagnostics. {CNN–
Transformer gives the strongest overall classification performance (accuracy = 0.8266), while boosted trees remain highly competitive for this low-dimensional tabular problem. In the binary
star-forming-versus-AGN comparison, CNN–
Transformer achieves a Class~1 versus Class~4 ROC AUC of 0.9998. Missingness indicators provide substantial predictive information, especially the OH\_P50N\_missing feature. Feature interpretation further shows that $\log([\mathrm{Ne\,III}]/[\mathrm{O\,II}])$, combined with
stellar mass or specific
star-formation rate, separates
star-forming
galaxies from AGN hosts. The models are most useful as AGN candidate-ranking tools that complement, rather than replace, traditional BPT diagnostics. High-ranked samples can reach high purity, while broader candidate lists recover most AGNs, but transferability to other surveys requires further validation.
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High Energy Physics (Phenomenology)
Strong First-Order Electroweak Phase Transitions and Gravitational Waves in the Normal Two-Higgs-Doublet Model: A Comparative Study of the Four Yukawa Types and Thermal Resummation Schemes
Jin-Hwan Cho, Dongjoo Kim, Jinheung Kim et al. (+2 more)
We present a comprehensive global analysis of strong first-order electroweak phase transitions (SFOEWPTs) and their associated
stochastic gravitational-wave (GW) backgrounds within the Normal Scenario of the $CP$-conserving Two-
Higgs-Doublet Model (2HDM) with softly broken $Z_2$
symmetry, where the lighter $CP$-even scalar is identified as the observed $125~\text{GeV}$
Higgs boson. Across all four Yukawa structures (Type-I, II, X, and Y), we track the finite-temperature
vacuum evolution, transition dynamics, and GW signatures. To quantify the theoretical uncertainty associated with thermal resummation, we perform a detailed comparison between the Parwani and Arnold–Espinosa prescriptions. While both schemes find that single-step paths overwhelmingly dominate successful transitions and consistently favor the
Higgs alignment limit, the resulting SFOEWPT parameter space exhibits a pronounced scheme dependence. The Arnold-Espinosa prescription severely restricts the viable parameter space (with upper bounds on the heavy-scalar masses below approximately 800 GeV) and introduces an extreme parametric sensitivity that produces fragmented distributions and irregular voids in the heavy-scalar mass planes. In contrast, the more stable Parwani prescription allows heavy-scalar masses below $\sim 1.6~\text{TeV}$. We further identify highly restricted GW parameter regions capable of yielding a four-year LISA signal-to-noise ratio above 10, while demonstrating that the acoustic GW source is generically short-lived, leading to a substantial suppression of the predicted signal amplitude. Our results highlight the strong complementarity between future space-based GW observations and high-energy
collider searches in probing the cosmological viability of the 2HDM.
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All authors Jin-Hwan Cho, Dongjoo Kim, Jinheung Kim, Soojin Lee, Jeonghyeon Song
General Relativity and Quantum Cosmology
Hawking Radiation in $f(\mathcal{R})$ Gravity: Survival of lighter black holes
Mriganka Dutta, Panchajanya Dey and Banibrata Mukhopadhyay
Einstein's theory of general relativity (GR) has been remarkably successful in describing gravitational phenomena. However, several open questions in modern cosmology and astrophysics (e.g. inflation, dark energy) suggest the need for extensions or modifications to this framework. Modified
gravity (MGR) theories, including scalar-tensor models and higher-dimensional approaches, attempt to address these gaps while maintaining consistency with established experimental tests. This work investigates Hawking radiation within an $f(\mathcal{R})$
gravity theory, with $\mathcal{R}$ being scalar
curvature, focusing on its implications for
primordial black holes (PBHs) as potential dark matter (DM) candidates. Our analysis reveals that PBHs evaporate slowly in MGR compared to GR predictions. Specifically, we find that non-rotating black holes with masses $\sim 5 \times 10^{13}$ g or lower would have survived by the present epoch, depending on the MGR parameter-a mass threshold approximately at least ten times smaller than in GR. This retarded evaporation timeline imposes relaxed new constraints on the viability of PBHs as DM constituents, thereby reshaping the landscape of possible solutions to the DM problem. This motivates further investigation into alternative gravitational theories and their cosmological consequences.
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Instrumentation and Methods for Astrophysics
Efficient Optimal Image Reconstruction for the Nancy Grace Roman Space Telescope and Beyond: II. Implementation of Effortless
Kaili Cao
Weak gravitational
lensing is a promising but technically demanding cosmological probe. For space missions like the forthcoming Nancy Grace Roman Space
Telescope, a major challenge is that native images are undersampled and need to be reconstructed to enable accurate measurements. Effortless (EFFicient Optimal image ReconsTruction using LESS
memory; previously known as Fast Imcom) is a new
algorithm designed for that purpose. My companion paper has exhibited promising first results to demonstrate that Effortless can make point spread functions (PSFs) uniform and regular across reconstructed images more efficiently than its predecessor Imcom and has the potential to outperform Imcom in terms of control over systematic errors. In this paper, I present the mathematical formalism, software implementation, and practical issues in detail. Foremost, while the Nyquist–Shannon sampling
theorem remains true, the conditions of the
theorem are subtly (and importantly) different from the problem in survey data processing, and finite sampling effects can be substantially reduced via a simple post-measurement calibration. Imperfections caused by numerical artifacts, finiteness of input pixel windows, and unavailability of some input pixels are understood and under control. The Effortless application programming interface is general and can support use cases beyond weak
lensing cosmology and beyond the Roman Space
Telescope.
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High Energy Physics (Phenomenology)
The Higgs boson through the lens of electroweak precision data
Yannick Fischer, Johannes Haller, Andreas Hoecker et al. (+5 more)
The global electroweak fit tests the
quantum structure of the Standard Model by confronting precision measurements with high-order theoretical predictions. This paper presents an updated Gfitter analysis using the latest experimental inputs, notably the new world average of the $W$-
boson mass, and state-of-the-art theoretical calculations. The fit yields indirect determinations of precision observables, including the $W$ and
Higgs-
boson masses, the top-
quark mass, and the effective leptonic weak mixing angle, confirming the remarkable internal consistency of the Standard Model. The analysis is further extended to the
Higgs sector by combining ATLAS and CMS signal-strength measurements with electroweak precision data in the $\kappa$ framework. The resulting electroweak constraints on the
Higgs couplings to vector
bosons allow a determination of the total
Higgs-
boson width with a precision of about 10% or better within a leading-logarithmic oblique interpretation, and provide bounds on invisible and undetected
Higgs-
boson branching fractions without using direct searches for invisible
Higgs decays. The paper also presents bounds on Wilson coefficients in the Standard Model Effective Field Theory together with projections for the precision of the global electroweak fit achievable at the FCC-ee.
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All authors Yannick Fischer, Johannes Haller, Andreas Hoecker, Roman Kogler, Finn Labe, Klaus Mönig, Dennis Schwarz, Jörg Stelzer
High Energy Physics (Phenomenology)
Benchmarking the Nearside Energy-Energy Correlators with Mellin Transform
Yuxun Guo and Feng Yuan
We investigate nearside energy-energy correlators (EECs) at small angles, explicitly incorporating the QCD scaling behavior in both the perturbative and post-confinement regimes through a Mellin-transform framework. As an illustration, we show that a single parameter, $\Lambda$, characterizing the transition scale between the two regimes, provides an excellent description of nearside EECs in $e^+e^-$ annihilation, including the recent ALEPH analysis as well as earlier measurements across different energies, with next-to-next-to-leading-order accuracy and next-to-next-to-leading-logarithmic resummation.
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Superconductivity
Landau-Zener tunneling and quantum interference of Andreev states
Mikhail S. Kalenkov and Andrei D. Zaikin
With the aid of a microscopic theory we derive an effective
Hamiltonian that controls
quantum dynamics of Andreev states in superconducting nanojunctions out of
equilibrium. Resolving the corresponding Schrödinger-like equation we obtain the "wave functions" for Andreev levels and evaluate electric current across the junction in the presence of an external voltage bias. We demonstrate that
quantum interference of Andreev states may yield pronounced coherent oscillations of the supercurrent as a function of the Josephson phase in junctions with barrier transmissions slightly below unity. Further implications of this novel effect are expected for junctions with diffusive barriers.
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Astrophysics of Galaxies
How Should We Understand the Core Mass Function? A memo of the CMF2IMF conference at ESO Garching
Fengwei Xu, Roberto Galvan-Madrid, Kaho Morii et al. (+4 more)
The origin of the
stellar initial mass function (IMF) remains one of the central questions in astronomy. Nearly three decades ago, the resemblance between the core mass function (CMF) and the IMF inspired the community to suggest that the
stellar mass spectrum might be imprinted early in molecular-cloud cores and then mapped to the IMF through a simple efficiency factor. It has become gradually clear, however, that this apparent mapping involves multiple non-linear physical processes. Motivated by the spirit of the CMF2IMF conference at ESO Garching, this memo first reviews the historical quest to understand the origin of the IMF, and then sets the stage for building a shared understanding of current CMF measurements. We therefore compile several observational core catalogues at various environments and evolutionary stages into a common framework, implemented in the public Python package CMF4All. We show that the inferred high-mass CMF slope depends strongly on the adopted minimum fitting mass. A significantly steeper slope is observed in the early-stage sample, indicating a potentially evolving mass function at the highest masses. We conclude by outlining future directions to spare more efforts for both the observational, numerical simulation, and theoretical sides.
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All authors Fengwei Xu, Roberto Galvan-Madrid, Kaho Morii, Thomas Nony, Aina Palau, Alessio Traficante, Alice Nucara
Quantum Physics
Gauge-invariant thermodynamics of a finite-time quantum Otto engine
Midana Baial Sambú, Thiago R. de Oliveira and Lucas C. Céleri
We investigate a finite-time
quantum Otto engine within the framework of gauge-invariant
quantum thermodynamics, using the Lipkin-Meshkov-Glick model as the working medium. In this formulation, thermodynamic quantities are defined on equivalence classes of thermodynamically indistinguishable states, leading naturally to gauge-invariant notions of work, heat,
entropy, and efficiency. We derive explicit expressions for these quantities and show that the usual work performed during the
unitary strokes decomposes into an invariant contribution, associated with changes in the instantaneous energy spectrum and populations, and a coherent contribution arising from finite-time
quantum coherences. This decomposition induces the corresponding splittings of engine efficiency and
entropy production, providing a
geometric interpretation of finite-time irreversibility and clarifying the role of coherence in work extraction. By analyzing the cycle's dependence on driving speed and system size, we identify the engine's operating region and investigate the influence of criticality. We show that crossing the critical region substantially reduces the parameter space in which the cycle operates as a heat engine. At the same time, whenever the engine condition remains satisfied, the discrepancy between the conventional and gauge-invariant descriptions becomes strongly suppressed, indicating that the gauge-invariant sector predominantly carries the extracted work. These results establish a direct connection between gauge-invariant thermodynamics, finite-time irreversibility, and work extraction in many-body
quantum thermal machines.
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High Energy Physics (Phenomenology)
Counting b-jets at the FCC-ee as a probe of top-quark flavor physics
Shaouly Bar-Shalom and Jose Wudka
We explore the sensitivity of a future FCC-ee to multi-TeV new physics (NP) that can generate vector, scalar and tensor
flavor-changing (FC) $eetu_k$ contact interactions ($u_k=u,c$ for $k=1,2$), probed via single top-
quark production, $e^+ e^- \to t \bar{u}_k, t \bar{u}_k \gamma$ (+ c.c.) and leading (following the top-
quark decay) to two- and four-jet signals, $e^+ e^- \to 2j + X, 4j + X$, where $X$ denotes any non-jet final-state particles. Our analysis exploits an approximately conserved Standard Model (SM)
quantum number introduced in [1] and termed "$b$-Parity" ($b_P$), which is applicable to scattering processes of the type $e^+ e^- \to n \cdot j_b + m \cdot j_\ell + X$, where $n$ and $m$ are the number of produced $b$-jets and light-jets ($u,d,c,s,$ and/or
gluons) and $b_P=(-1)^n$. The FC $eetu_k$ four-
fermion interactions can generate distinct $b_P$-odd ($b_P = -1$) signals in these multi-jet events, for which the only significant SM background stems from $b$-jet misidentification. We demonstrate that the FCC-ee, operating at a $\sqrt{s} = 240$ GeV (the $ZH$ run phase) with high luminosity and excellent
flavor-tagging performance, is an ideal platform to search for these $b_P$-odd signatures. Indeed, by simply counting the number of final-state $b$-jets, the FCC-ee can probe NP scales of $\Lambda \sim 10$ TeV for the new heavy states that generate the vector, scalar and tensor $eetu$ and/or $eetc$ interactions. This reach, remarkably about 40 times the assumed FCC-ee center-of-mass energy, improves upon current bounds on some of these four-
fermion operators by an order of magnitude and it critically relies on high-purity b-jet tagging.
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Quantum Physics
Ergotropic and passive contributions on the phase-space information geometry of Gaussian states
Ivan Medina, Camila Raupp, Pedro B. Melo et al. (+1 more)
We establish a direct connection between
quantum thermodynamics and information geometry by introducing an ergotropic decomposition of the Wigner-Fisher information for Gaussian
quantum states. We derive an analytical expression for the Wigner-Fisher information in terms of the phase-space covariance
matrix and mean vector, and show that it naturally separates into passive and ergotropic contributions. The passive term is shown to be entirely determined by the Wigner
entropy rate of the associated passive state. The ergotropic contribution, in turn, quantifies how displacement and squeezing resources modify the statistical velocity and length of the system trajectory in phase space. As an application, we analyze the recently proposed ergotropic Mpemba effect and demonstrate that it can be traced to the anomalous
geometric evolution of the passive state associated with squeezed thermal states. Our results reveal how the extractable work stored in a
quantum state constrains its information-
geometric structure, establishing a framework that links ergotropy,
entropy production rate, and statistical geometry in continuous-variable
quantum systems.
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All authors Ivan Medina, Camila Raupp, Pedro B. Melo, Diogo O. Soares-Pinto
General Relativity and Quantum Cosmology
GRACE: An Open-Source Framework for GPU-Accelerated Numerical Relativity
Carlo Musolino, Christian Ecker, Konrad Topolski et al. (+6 more)
We present GRACE, a new GPU-accelerated numerical-relativity framework designed to run efficiently on heterogeneous high-performance computing platforms. Developed from scratch and built exclusively on open-source libraries, GRACE employs Kokkos for performance portability across CPU and GPU architectures and p4est for adaptive mesh refinement. The code evolves the equations of ideal GRMHD – with divergence-free
magnetic fields maintained by constrained transport – self-consistently coupled to the Einstein equations in the Z4c formulation, on fixed or adaptively refined grids. We validate the implementation against a suite of standard tests, ranging from magnetized shock tubes and the
magnetic rotor in flat spacetime, through (magnetized) Bondi
accretion onto a Schwarzschild black hole and the ringdown of a perturbed spinning puncture, to
neutron-
star oscillation spectra in fixed and dynamical spacetimes and the merger of binary black holes. As more demanding applications, we evolve two binary
neutron-
star mergers – an equal-mass, unmagnetized system with an ideal-gas equation of state and an unequal-mass, magnetized system with a finite-temperature tabulated equation of state – finding the inspiral dynamics to agree well with the FIL code. We also report single-device throughput together with strong- and weak-scaling results on multiple GPU and CPU architectures. GRACE is publicly released together with GRACEpy, a basic post-processing and data-analysis environment.
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All authors Carlo Musolino, Christian Ecker, Konrad Topolski, Marie Cassing, Keneth Miler, Harry Ho-Yin Ng, Khalil Pierre, Elias R. Most, Luciano Rezzolla
Astrophysics of Galaxies
The black hole occupation fraction as a fossil record of seeding, dynamics, and galaxy assembly
Emma Jane Weller, Priyamvada Natarajan and Colin J. Burke
The black hole occupation fraction (BHOF) is a powerful but intrinsically layered diagnostic of massive black hole (BH) seeding and subsequent
galaxy assembly. We measure the total, central, and wandering BHOF in the ASTRID cosmological hydrodynamical simulation from $z=5$ to $z=0$ in
galaxies with
stellar masses ranging from $10^7$-$10^{12} \, \mathrm{M}_\odot$. For the full population, the total BHOF remains close to unity across most
stellar masses and
redshifts, reflecting efficient seeding in eligible
halos. At low
stellar masses, the central BHOF declines toward the present day, while the wandering BHOF rises, indicating that mergers deposit BHs at off-center locations in
galaxies. Compared to these full-population BHOFs, the heavy-seed BHOFs are substantially smaller at the low-mass end. The active BHOFs are smaller at all
stellar masses, especially at late times, demonstrating that active
galactic nuclei (AGN)-selected samples trace duty cycles rather than intrinsic BH occupation. At $z=0$, primary (central)
galaxies have higher BHOFs than satellites, and
star-forming low-mass
galaxies preferentially host wandering rather than central BHs. Our results show that the BHOF, when decomposed by BH location, seeding history,
accretion state, and larger-scale
galactic environment, encodes a rich fossil record of BH origins and dynamics.
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High Energy Physics (Phenomenology)
Darkly Charged ALPs
Nicolás M. Arenaza, Enrique Fernández-Martínez, Belén Gavela et al. (+4 more)
The established $d=5$ ALP effective Lagrangian describes the interaction of scalars with approximate shift-
symmetry which carry no Standard Model (SM) charges with SM fields. It implicitly assumes that ALPs are not charged under any
symmetries of the dark sector. In this paper, we remove this assumption. For ALPs carrying conserved dark charges, no $d=5$ ALP effective interaction to SM particles is possible. We build the effective Lagrangian for these darkly charged ALPs stemming from a general breaking pattern, and we show that the lowest-order shift-symmetric effective Lagrangian contains just two $d=6$ operators coupling ALPs to SM particles. We explore the model-independent phenomenological implications of these interactions, as well as the question of whether the dark matter observed in the Universe may consist of darkly charged ALPs. We identify higher order operators of the effective field theory, and determine which types of dark
symmetry groups can seed darkly charged ALPs. Illustrative examples of ultraviolet completions which result in darkly charged ALPs at low-energies are provided as well. The darkly-charged ALP scenario can be generalized by including dark gauge interactions. In this paper, we have considered only the case with no such interactions.
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All authors Nicolás M. Arenaza, Enrique Fernández-Martínez, Belén Gavela, Elizabeth E. Jenkins, Aneesh V. Manohar, Pablo Quílez, Thomas Steingasser
Solar and Stellar Astrophysics
Benchmark Brown Dwarf Systems I: Chemical Abundance Analysis of FGK Stars with Wide-Separation Brown Dwarf Companions Using PEPSI
Caprice L. Phillips, Megan Bedell, Catherine Manea et al. (+11 more)
We present results from a spectroscopic survey of 32 FGK
stars hosting brown
dwarfs, using high-resolution optical spectra (R = 130,000 and 50,000) obtained with the PEPSI spectrograph on the Large Binocular
Telescope. The primary goal of this survey is to determine precise
stellar parameters and abundances for 11 elements (C, O, Mg, Si, Ca, Al, Ti, Fe, Y, S, and N) in these systems. We employ spectral synthesis within the BACCHUS framework to derive precise
stellar properties and elemental abundance ratios. For our average S/N $>$ 200 data, we achieve a typical error of 42 K in T$_\mathrm{eff}$ and $\sim$0.03 dex for [Fe/H]. We observe a significant dispersion from a
solar C/O ratio among the sample of brown
dwarf host
stars that host primarily wide-orbit brown
dwarfs. Using established theoretical chemical frameworks, we discuss the implications of the observed Mg/Si and Ca/Al ratios for cloud properties in the brown
dwarf companions. Finally, we evaluate the applicability of the [Y/Mg]
stellar clock for our sample and discuss the broader implications of our results. This work provides a timely and uniform abundance analysis of host
stars, supporting extended wavelength brown
dwarf observations in the era of JWST.
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All authors Caprice L. Phillips, Megan Bedell, Catherine Manea, Alison Duck, Anusha Pai Asnodkar, Emily J. Griffith, Austin Rothermich, Emily Calamari, Jaqueline K. Faherty, Channon Visscher, Eileen C. Gonzales, Ilya Ilyin, Klaus Strassmeier, Ji Wang
High Energy Astrophysical Phenomena
Low-hard to high-soft spectral state transitions in the faintest early-X-ray-detected optical tidal disruption event TDE 2025aarm
Pietro Baldini, Arne Rau, Andrea Merloni et al. (+11 more)
We report the X-ray and optical spectroscopic properties of TDE 2025aarm, the second closest
tidal disruption event (TDE) discovered to date. The proximity of this source, combined with a deep and intense X-ray monitoring campaign spanning six months, allowed us to probe the source down to an unprecedented 0.2-10 keV luminosity of $\sim7\times10^{39}$ erg s$^{-1}$ close to the optical peak. This renders TDE 2025aarm the faintest early-X-ray-detected TDE to date. After the first X-ray detection, the source brightened by nearly two orders of magnitude, reaching a peak luminosity of $\sim5\times10^{41}$ erg s$^{-1}$ about four months after the optical peak. Through time-resolved X-ray spectral analysis, we find that TDE 2025aarm evolved from an initially hard, power-law-dominated X-ray state into a softer, disk-dominated state as the luminosity increased, before hardening again at later times. Such low-hard-to-high-soft state transitions are commonly observed in black hole X-ray binaries (XRBs) but have not previously been reported in thermal TDEs. We show that the spectral
evolution can be described by variations in the relative contributions of an
accretion disk and a Comptonizing component, qualitatively resembling the disk–corona
evolution observed in XRBs. We also present the results of our optical spectroscopic follow-up campaign with HET/LRS2, confirming the TDE classification and revealing NIII Bowen fluorescence features. The extremely faint early-time X-ray emission of TDE 2025aarm further supports the idea that the historical dichotomy between X-ray-bright and X-ray-undetected TDEs is largely driven by selection effects related to the depth, cadence, and duration of X-ray follow-up observations. TDE 2025aarm therefore provides new insight into both the
accretion physics of TDEs and the possible universality of
accretion across several orders of magnitude in black hole mass.
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All authors Pietro Baldini, Arne Rau, Andrea Merloni, Jean Somalwar, Seán J. Brennan, Elias Kyritsis, Hannah C. I. Wichern, Peter Boorman, Panos Charalampopoulos, Lixin Dai, Gaurava K. Jaisawal, Chichuan Jin, Tianying Lian, Kirpal Nandra
Instrumentation and Methods for Astrophysics
Robust Photometry for Roman High-Latitude Imaging Survey Cosmology Using Roman and Rubin Imaging
Chun-Hao To, Tae-Hyeon Shin, Chihway Chang et al. (+18 more)
Accurate and precise photometry is essential for Roman cosmology because it affects photometric-
redshift performance,
galaxy and cluster selection, tomographic binning, and
redshift-distribution characterization. Achieving robust photometry is challenging because Roman's depth leads to substantial source blending, particularly in joint Roman–Rubin analyses, where the two surveys have different spatial resolutions. In this work, we develop and validate slimfarmer, a model-fitting photometry pipeline designed for Roman High-Latitude Imaging Survey (HLIS) cosmological analyses. Building on The Farmer, slimfarmer introduces treatments of the correlated noise present in Roman images and of astronomical shot noise, together with model-fitting configurations tuned for Roman imaging. We validate the pipeline using Roman coadded simulated images and perform forced photometry on matched Rubin image simulations. We find that slimfarmer recovers
galaxy colors with the mode of the color residuals within 20 millimag for Roman-based colors and within 70 millimag for Rubin-based colors. Properly accounting for correlated noise is essential for uncertainty quantification, as photometric uncertainties are otherwise underestimated by up to a factor of ~3. We also find that applying multi-object fitting consistently to both Roman and Rubin imaging substantially mitigates blending-induced color systematics. In crowded regions, single-object fitting produces environment-dependent color biases of up to ~0.5 mag, leading to environment-dependent degradation of photometric-
redshift performance. Together, these results establish slimfarmer as a prototype photometric pipeline for Roman HLIS cosmology applications and identify the correlated-noise corrections, astronomical shot-noise treatment, and joint Roman–Rubin multi-object fitting required for robust photometric-
redshift characterization.
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All authors Chun-Hao To, Tae-Hyeon Shin, Chihway Chang, Christopher Hirata, Brett H. Andrews, Ami Choi, Boyan Yin, Rachel Mandelbaum, Federico Berlfein, Kaili Cao, James Chiang, Nihar Dalal, Yuedong Fang, Axel Guinot, Michael Gabe, Andrew Hearin, Katherine Laliotis, Emily Macbeth, Sidney Mau, Edward F. Schlafly, M. A. Troxel
Astrophysics of Galaxies
Do we understand the star formation history of the universe?
Sahil Hegde, Steven R. Furlanetto and Smadar Naoz
The evolving relationship between a
galaxy's mass and
star formation rate – the so-called `
star-forming main sequence' (MS) – provides a critical
benchmark for understanding
star formation across time. Despite its fundamental importance, the observed main sequence remains subject to substantial systematic uncertainties in normalization, shape, and
redshift evolution, and a longstanding discrepancy persists between the main sequence and its integral, the
stellar mass function. We revisit the
star-forming MS in the era of the James Webb Space
Telescope by asking what
star formation rates are required by the
stellar mass function to create a self-consistent picture of
galaxies across time. We fit compiled ground- and space-based measurements of
star-forming and quiescent mass functions from $z=0.1-9$. By tracing
galaxy growth histories through these mass functions, we present a statistically-robust inference of the main sequence over $10^8 M_\odot \leq m_\star \leq 10^{11} M_\odot$, from the local universe to the first 500 Myr of
cosmic history. Our procedure implies a main sequence that agrees with independent spectroscopic measurements of
star formation rates from $z\sim 2-7$, is consistent with SED fitting-based analyses of photometric samples at $z\lesssim 3$, and aligns with theoretical models of
galaxy evolution. However, we find that our MS differs from commonly-used `concordance' relations and thus caution against applications of these compilations without appropriately characterizing the underlying uncertainties. Finally, we explore the implications of our inferred main sequence for the
galaxy-
halo connection and
star formation rate density, highlighting the need for further theoretical work to comprehensively understand the
star formation history of the universe.
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High Energy Physics (Theory)
Carrollian limit of NS-NS and Heterotic Supergravity
Romina Ballesteros, Eric Lescano and Sergio Patiño-López
We construct the Carrollian limit of NS–NS and heterotic supergravity through an ultra-relativistic expansion of the fields. An appropriate scaling of the dilaton renders the measure finite and compensates the divergences arising from the NS-NS supergravity Lagrangian, giving a finite action as $w\rightarrow\infty$. We then extend the construction to heterotic supergravity (neglecting
fermions) by incorporating the non-Abelian gauge field together with the Green–Schwarz (GS) mechanism. The resulting theory contains a finite gauge sector consistently coupled to
gravity, and the GS mechanism for the Carrollian 1-form field can be trivialized imposing field redefinitions. Then, we investigate the Carrollian equations of motion by both expanding the relativistic equations and deriving them from a variational principle. We also show that the leading $\alpha'$-corrected $\hat{\rm Riem}^2$ contribution remains finite under a rescaling of the string parameter $\alpha'\rightarrow \frac{\alpha'_c}{w^2}$, opening further research towards the full four-derivative effective action. Finally, we discuss the potential connection with the worldsheet formalism of the Carrollian string theory.
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Cosmology and Nongalactic Astrophysics
The Rise and Fall of Acoustic Oscillations at Cosmic Dawn
Hector Afonso G. Cruz, Gabriele Montefalcone, Julian B. Muñoz et al. (+2 more)
Cosmic dawn 21-cm observations will extend standard-ruler cosmology into the first billion years, unlocking epochs inaccessible by the
cosmic microwave background and large-scale structure. Realizing this promise requires an accurate model of the acoustic structure imprinted onto early
star formation. At such early times, two counterbalancing phenomena – matter overdensities and streaming velocities between cold dark matter and
baryons – modulate the spatial statistics of
star formation. While overdensities dictate where early
galaxy-bearing
haloes form, regions of high velocity suppress
star formation. Their combined influence on the intergalactic medium yields 21-cm fluctuations with both
baryon (BAO) and velocity-induced (VAO) acoustic oscillations. Here we present the first prescription to decompose the 21-cm power spectrum into its constituent acoustic features. We find a percent-level offset between the BAO and VAO shapes which, if ignored in standard-ruler analyses, would bias inferred values of $H(z)$ by $\sim 2\%$; we provide a correction. Moreover, as the relative prominence of BAOs and VAOs ebbs and flows non-monotonically across
cosmic dawn, we demonstrate how their
evolution is sensitive to the physics of early
galaxy evolution and the first
stars. Finally, we forecast how sensitive SKA will be to the BAO-VAO combined standard ruler. Our results establish joint BAO-VAO modeling as an essential ingredient of 21-cm acoustic inference, enabling robust constraints on both
cosmic expansion and the first
stars.
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All authors Hector Afonso G. Cruz, Gabriele Montefalcone, Julian B. Muñoz, Ely D. Kovetz, Alessandra Venditti