High Energy Physics (Phenomenology)
DarkAgents
Michele Lucente, Silvia Pascoli, Filippo Sala et al. (+1 more)
We present DarkAgents: a multi-
agent system that leverages the
reasoning and code-generation capabilities of large
language models (LLMs), together with deterministic tested human-written code, to build orchestrated pipelines for theoretical astroparticle physics research. While related approaches have been proposed in
collider physics and cosmology, DarkAgents targets the specific challenges of this domain, such as model building, complex pipeline computations, multiple constraints and assumption
auditing. The framework can be powered by different agentic command-line tools, including Mistral's, Anthropic's, OpenAI's and local LLMs via Ollama. As first implementation, we apply DarkAgents to the study of cosmological first order transitions, starting from a classically scale-invariant particle-physics model and ending with the fit to the NANOGrav nanohertz gravitational-waves spectrum. DarkAgent-PT provides as output i) the best-fit values of model parameters, ii) their existing experimental and observational constraints, iii) an audit report of the assumptions and priors entering both i) and ii), of particular relevance for astroparticle physics. Our test runs identify inconsistencies in some fits in the literature and produce novel ones based on the dissipative bulk-flow GW template. The code is publicly available at https://github.com/PhysicsZandi/DarkAgents.
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All authors Michele Lucente, Silvia Pascoli, Filippo Sala, Matteo Zandi
Nuclear Theory
Quantum Monte Carlo calculations of Zemach moments in $A\leq 9$ nuclei
Garrett B. King, Sonia Bacca, Graham Chambers-Wall et al. (+4 more)
Modern atomic spectroscopy has reached a level of precision at which
nuclear-structure effects can no longer be neglected and must be quantified reliably. In particular, hyperfine splittings depend on the Zemach radius, which encodes the convolution of the
nuclear charge and magnetization distributions. The third electric Zemach moment provides a related finite-size measure and enters the elastic two-
photon-exchange contribution to the Lamb shift in muonic atoms. Here, we compute Zemach radii and other electromagnetic moments for light
nuclei using
quantum Monte Carlo techniques within modern ab initio
nuclear theory. Using Norfolk two- and three-body interactions derived within
chiral effective field theory, we assess the model dependence and study the role of two-body currents. For $^6$Li, we obtain a Zemach radius larger than that extracted from atomic measurements, consistent with recent calculations, confirming that the discrepancy is not an artifact of the
nuclear model. For $^9$Be, our results agree with experiment; the discrepancy of previous phenomenological evaluations is traced to a model-dependent input for the
magnetic radius.
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All authors Garrett B. King, Sonia Bacca, Graham Chambers-Wall, Alex Gnech, Saori Pastore, Maria Piarulli, Robert B. Wiringa
Mesoscale and Nanoscale Physics
Quantum statistics in an extended collider coupled to a qubit
Rishav Chaudhuri and Sai Satyam Samal
Mesoscopic
colliders provide an effective platform for probing the mutual statistics of
quantum particles. Recent experiments have successfully extracted the mutual statistics of
fermions, and more exotic anyons using
quantum point contacts (QPCs). Coupling a point-like
collider, such as a
quantum point contact, to a two-level
impurity or
qubit can induce statistical transmutation of
fermions, causing them to display
boson-like bunching tendencies. Here, we extend the analysis to an extended
collider. We investigate the scattering of two incoming fermionic and bosonic wave packets in the presence of postselection on the
impurity state, and systematically analyze the possible
benchmarks used to characterize bunching and infer the underlying mutual statistics. We show that only a specific
benchmark faithfully captures the mutual statistics of the colliding particles, while alternative choices can produce spurious statistical signatures. Hence, the correct
benchmark for probing the
quantum statistics depends on the intricate details of the mesoscopic
collider.
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Mathematical Physics
The Yang-Baxter Equation for the Chiral Potts Model and Integrable Parafermions
Zhao Zhang
A new type of Yang-Baxter equation (YBE) for $R$-operators depending on three spectral parameters is constructed from the
star-triangle relation for the
chiral Potts model. As the $Z_N$ symmetric generalization to the Ising model, its Boltzmann weights are known to depend on two variables describing a curve with genus larger than one for $N>2$, except for the self-dual point corresponding to the Fateev-Zamolodchikov chain. Combined with the fact that
quantum Hamiltonians of edge-type models such as the Ising model contain both nearest-neighbor interaction and onsite potential terms, this leads naturally to an additional spectral parameter in the associated $R$-operator. The construction extends the edge-vertex correspondence of solvable
lattice models, and provides a bridge between the Bazhanov-Stroganov four-parameter $R$-
matrix—realized as an intertwiner of cyclic representations of $U_q(\mathfrak{sl}_2)$ at a root of unity—and Shastry's two-parameter $R$-operator obtained from the decorated YBE.
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Nuclear Experiment
Hindered $\Delta K=1$ Dipole Strength in octupole bands in $N=90$ $^{154}$Gd from Lifetime Measurements with $\gamma-\gamma$ fast timing technique
A. Pal, S. Basak, D. Kumar et al. (+7 more)
The lifetimes of the low-lying negative-parity $1^-$ state at 1414~keV and $2^-$ state at 1398~keV in $^{154}$Gd have been measured using the $\gamma$–$\gamma$ fast-timing technique with the VENTURE array at VECC, Kolkata. The states were populated through the $\beta$ decay of $^{154}$Tb, produced in
proton-induced reactions at the K130 cyclotron. From the measured lifetimes, absolute $B(E1)$ transition strengths were deduced. The extracted $B(E1)$ values are compared with those of neighboring Gd isotopes and with Gogny-HFB-based $sdf$-IBM calculations. The results show that the measured $E1$ strengths from these states are strongly hindered compared with the corresponding $\Delta K=0$ transitions, providing evidence for weak $\Delta K=1$ dipole strength in $^{154}$Gd.
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All authors A. Pal, S. Basak, D. Kumar, T. Bhattacharjee, B. Maheshwari, K. Nomura, P. Van Isacker, D. Banerjee, S. S. Alam, A. K. Jain
Geophysics
Data assimilation for subsurface flow using latent diffusion model parameterization: performance of ensemble-Kalman and Monte Carlo techniques
Guido Di Federico, Wenchao Teng and Louis J. Durlofsky
Data assimilation (DA) in subsurface flow entails calibrating model parameters to match observed data, typically at wells, while preserving geological realism. Latent
diffusion models (LDMs) provide efficient mappings from high-dimensional geological model space to a low-dimensional latent variable, reducing the dimensionality of the inverse problem while maintaining plausibility in posterior geomodels. However, the high nonlinearity in the LDM mapping may degrade the performance of Kalman-gain-based ensemble updates. We present a systematic comparison of DA
algorithms applied to large-scale 3D channelized geomodels with hierarchical geological uncertainty. We compare model-space and latent-space DA using the ensemble smoother with multiple data assimilation (ESMDA), and demonstrate a key trade-off: model-space updates achieve significant uncertainty reduction but produce geologically unrealistic posterior models, while latent-space updates preserve realism but exhibit limited uncertainty reduction. Motivated by this, we explore rigorous Markov chain Monte Carlo (MCMC) and Sequential Monte Carlo (SMC)
algorithms in the 3D-LDM latent space. To accommodate their high computational demands, we develop a fast surrogate flow model that approximates well-rate responses. MCMC and SMC are evaluated against ESMDA across three synthetic test cases, with DA performed in the LDM latent space. All models maintain geological realism due to the LDM parameterization. MCMC and SMC are consistent with one another and achieve lower data mismatch and more uncertainty reduction than latent-space ESMDA. Our overall results demonstrate that ensemble Kalman methods may provide overestimated posterior uncertainty with highly nonlinear parameterizations, while rigorous Monte Carlo sampling, enabled by fast surrogate models, can provide a more reliable alternative.
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High Energy Astrophysical Phenomena
Resolving SLX 1744-299 and SLX 1744-300 in the hard X-ray band: implications for their ultracompact nature
Enzo A. Saavedra, Montserrat Armas Padilla and Teo Muñoz-Darias
Persistent, low-luminosity low-mass X-ray binaries (LMXBs) offer a unique opportunity to study
accretion in this poorly understood regime, as well as to unveil new members of the ultracompact X-ray binary (UCXB) family, characterised by orbital periods ($P_{\rm orb}$) shorter than $\sim 80$ min. We report on a NuSTAR archival observation that, for the first time above 10 keV, spatially resolves the
Galactic Centre pair SLX 1744$-$299 and SLX 1744$-$300. We find SLX 1744$-$300 to be slightly brighter, with a flux ratio of $\sim 1.15$, increasing to $\sim 1.3$ when extrapolated to 0.5$-$10 keV. Both the timing (root-mean-square variability) and spectral properties (well described in both cases by a thermal Comptonisation model) indicate that the systems were in the hard state. The two sources, however, display markedly different behaviour throughout the observation. SLX 1744$-$299 shows a gradual flux decline consistent with a decrease in the mass-
accretion rate, whereas SLX 1744$-$300 remains steady but exhibits two short-recurrence Type-I X-ray bursts indicative of mixed H/He burning. Combining our results with previously reported upper limits on the distance, we derive low persistent X-ray luminosities of $L_{\rm X}\lesssim 1.1\times10^{36}$ erg s$^{-1}$ and $L_{\rm X}\lesssim 2.6\times10^{36}$ erg s$^{-1}$ (3$-$78 keV) for SLX 1744$-$299 and SLX 1744$-$300, respectively. The corresponding mass-
accretion rates, when compared with the critical values from the disc instability model, favour $P_{\rm orb}\lesssim 90$ min and $P_{\rm orb}\lesssim 105-155$ min. Although both limits are formally compatible with the UCXB regime, the case of SLX 1744$-$299 appears significantly more compelling, also considering the previously reported intermediate-duration burst.
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Materials Science
Roughness-robust surface altermagnetism in $PT$ antiferromagnets
K. D. Belashchenko
Surface altermagnetism extends
spin splitting beyond bulk altermagnets through
symmetry reduction at surfaces and interfaces. An existing classification applies to the local
symmetry of atomically flat surface terraces. The present paper addresses the
symmetry of macroscopic
spin-momentum correlations that survive averaging over compensated rough surfaces. These correlations are governed by the surface antisymmetry Laue point group. Rough-surface altermagnetism is forbidden at any surface of a magnet whose antisymmetry space group contains antitranslations, and the classification therefore reduces to $PT$-symmetric antiferromagnets. By restoring all
symmetries leaving the surface normal invariant, roughness can generate compensated surface altermagnets from uncompensated flat terminations, increase the surface
symmetry, or suppress
spin splitting. By combining bulk switchability with altermagnetic surface transport properties, roughness-robust surface altermagnetism in $PT$-symmetric antiferromagnets provides a route toward spintronic functionality.
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Fluid Dynamics
Inertial effects on the mechanical efficiency of a semi-passive oscillating hydrofoil energy harvester
Zihan Zhang, Qimin Feng, Yuanhang Zhu et al. (+1 more)
Oscillating-foil-based energy harvesters have demonstrated strong potential for low-speed hydrokinetic energy extraction; however, the actuator-level mechanical energy balance associated with prescribed pitching motion remains poorly understood. The present work experimentally characterizes how foil mass ratio, pitching-axis location, and reduced frequency jointly govern the hydrodynamic and mechanical efficiencies of a semi-passive oscillating hydrofoil. Results show that rotational inertia redistributes actuator demand through phase-dependent torque exchange, while heave-pitch coupling can partially cancel this demand when favorably phased. Pitching-axis location modifies the phase and direction of the fluid torque through changes in the effective hydrodynamic moment arm. Reduced frequency governs the balance between enhanced unsteady loading and inertia-amplified actuator demand. Optimal performance is achieved within reduced frequency region of 0.125-0.16 using quarter-chord to one-third-chord pitching axes and relatively low foil mass ratios from about 0.5 to 2.0, yielding a peak mechanical efficiency of 33.96% – which can diverge from the hydrodynamic efficiency by approximately 38.16% depending on configuration. Torque-loop analysis and PIV measurements show that this synchronization is a key mechanism governing the observed efficiency trends.
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All authors Zihan Zhang, Qimin Feng, Yuanhang Zhu, Qiang Zhong
Solar and Stellar Astrophysics
GASTAG evolutionary tracks and isochrones from coupled 1D and 3D models: Systematic temperature offsets in red giants
Yixiao Zhou, Jiaqi Ying, Yaguang Li et al. (+1 more)
Models of
stellar structure and
evolution describe the global and internal properties of
stars throughout their lifetimes and are indispensable for studies of
stellar clusters and
Galactic evolution. However, most 1D evolutionary calculations rely on simplified treatment of convection, resulting in inaccurate near-surface structures and non-negligible uncertainties in the predicted fundamental parameters of low-mass
stars. In a series of previous works, a novel approach was developed to couple 1D
stellar interior models with 3D model atmospheres throughout the evolutionary calculation. This 1D-3D coupling method makes predicted
stellar properties effectively independent of the mixing-length parameter. To expand this framework to ensemble studies of
stars and age determinations of clusters, we present the GASTAG
stellar evolutionary tracks and isochrones constructed using the 1D-3D coupling approach. Comparing effective temperatures from the APOGEE-Kepler catalog with GASTAG predictions, we find the theoretical temperatures are cooler by about 70 K near
solar metallicity. Our isochrones are compared with observed color-magnitude diagrams of
star clusters spanning from $\rm [Fe/H] = 0.3$ to $-1.9$. In all cases, the synthesized and observed diagrams agree excellently in the main-sequence, turn-off, and subgiant regions, while isochrones predict systematically cooler red
giant branches. Taking these independent findings together reveals that the temperature mismatch is most likely due to deficiencies in
stellar models. Because GASTAG is constructed using a method that substantially reduces uncertainties associated with surface boundary conditions and the mixing-length parameter, the difference between modeling and observation can be more confidently attributed to other ingredients in the models, such as $\alpha$-element abundances or uncertainties in low-temperature opacities.
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All authors Yixiao Zhou, Jiaqi Ying, Yaguang Li, Luca Casagrande
Astrophysics of Galaxies
The Doppler effect of the Milky Way rotation on mHz gravitational waves
Giorgio Mentasti and Quentin Baghi
We model the
stellar density and the rotation curve of the Milky Way and compute the gravitational-wave spectrum of its unresolved binaries as a function of direction. Because the
Galaxy rotates, the waves emitted along each line of sight are Doppler-shifted by a different amount, and we derive for the first time the resulting observed anisotropic spectrum, which no longer factorizes into a spectral shape times an angular template. We then quantify the observability of this distortion with space-based interferometers. With their nominal noise budgets, neither LISA nor a LISA+Taiji network can detect it: the residual between the models that include and neglect the rotation has a signal-to-noise ratio ${\rm SNR}_{\rm diff}\simeq0.2$ and $0.7$ after two years, and the induced bias on the foreground parameters stays below $0.1\sigma$. A tenfold better noise amplitude, of the order contemplated for post-LISA concepts, raises the residual to ${\rm SNR}_{\rm diff}\simeq4.6$ for the network, where the effect becomes measurable and displaces the spectral cutoff by half of the statistical error.
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Materials Science
Flower-like WO3-modified Vulcan carbon GDEs for photoelectro-Fenton process: Efficient ciprofloxacin degradation and mechanistic insights
João Paulo C. Moura, Vanessa S. Antonin, Caio Machado Fernandes et al. (+8 more)
Electrochemical H2O2 synthesis was investigated using a 3 percent WO3 C gas
diffusion electrode GDE. The catalyst outperformed bare Vulcan carbon, generating H2O2 concentrations of 423, 586, and 916 mg L at 50, 75, and 100 mA cm2, respectively, maintaining around 70 percent current efficiency. This performance and lower energy consumption are attributed to the WO3 carbon synergistic effect. In electro Fenton EF applications, the WO3 C GDE achieved rapid initial ciprofloxacin CIP degradation of around 70 percent in 30 min, though limited later by slow Fe2 regeneration. Incorporating UV light photoelectro Fenton overcame this constraint, yielding complete CIP removal within 90 min, while a boron doped diamond BDD anode enhanced total organic carbon TOC mineralization to 66 percent. The proposed degradation mechanism proceeds via hydroxyl radical attack on the piperazine ring with or without defluorination and quinolone ring oxidation, with theoretical analysis confirming reduced environmental toxicity of the transformation products. Overall, WO3 C GDEs represent a highly efficient strategy for H2O2 generation and wastewater remediation.
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All authors João Paulo C. Moura, Vanessa S. Antonin, Caio Machado Fernandes, Aline B. Trench, Erica S. Conrado, Michell O. Almeida, Kathia M. Honorio, Renata Colombo, Rafael Sotana, Ana M.P. Neto, Mauro C. Santos
Medical Physics
Spatially heterogeneous power-law attenuation with multiple relaxation mechanisms for ultrasound modeling
Masashi Sode and Gianmarco Pinton
Objective. The soft tissue attenuation laws have a magnitude and frequency dependence that varies across tissue types and generally follow power laws. An accurate model of ultrasound propagation in the human body thus may require spatially heterogeneous power-law attenuation alpha(x,f) = alpha_0(x) f^(y(x)). However, a spatially heterogeneous representation of frequency-dependent attenuation is technically challenging, so existing methods introduce simplifying assumptions. For example, prior approaches such as Fullwave 2 achieved <5% error for individual tissue types but required manual parameter tuning for each (alpha_0, y) pair, limiting the construction of realistic tissue libraries. Approach. We introduce a calibration framework that uses derivative-free optimization to systematically fit relaxation parameters across diverse tissue combinations spanning alpha_0 = 0.0022-1.0 dB/(MHz^y cm) and y = 0.4-2.0. The Nelder-Mead
algorithm minimizes complex-wavenumber mismatch. The attenuation is extended to a convolutional perfectly matched layer, where the same relaxation formulation is used in the boundaries. Main results. The method achieves mean errors below 3% over 1-20 MHz with dispersion error of 1.1 +/- 0.8 m/s across the clinically relevant core region (y = 0.7-1.4). Boundary reflections remain below -50 dB for clinically relevant tissue exponents (y <= 1.5). We validated the method with two-layer muscle/fat/liver models and confirmed per-layer accuracy (<2.5% normalized error). A 3D abdominal simulation using the Visible Human
dataset demonstrates stable propagation with voxel-level heterogeneity in both alpha_0(x) and y(x). Significance. The open-source multi-GPU implementation (Fullwave 2.5) provides a practical tool for patient-specific therapy planning, training data generation, estimation of acoustic radiation force, quantitative imaging, and inverse problem applications.
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Instrumentation and Methods for Astrophysics
The Ohio SETI Program – The Last Decades
Abel Méndez, Robert S. Dixon and Russell K. Childers
The Ohio State University
Radio Observatory (OSURO), known as the Big Ear, played a pivotal role in both
radio astronomy and the Search for Extraterrestrial Intelligence (SETI). Following the completion of the Ohio Sky Survey, the facility was repurposed in 1973 as the world's first full-time dedicated SETI observatory and operated continuously until its decommissioning in 1998. During this period, the Ohio SETI Program evolved from an 8-channel hydrogen-line receiver into increasingly sophisticated survey systems. Over three decades, these surveys covered approximately 70% of the
radio sky using a largely consistent instrumental configuration, creating one of the most extensive long-term
radio astronomy archives ever assembled. The program is best known for the detection of the Wow! Signal in 1977, but it also accumulated an archive of over 40,000 transient narrowband events, revealed unusual concentrations of
radio bursts near the
Galactic Center, and established one of the longest continuous
radio monitoring records in astronomy. Following the closure of the Big Ear, its scientific legacy continued through Project Argus and, more recently, the Arecibo Wow! project. This paper provides an overview of the final decades of the Ohio SETI Program, including its instrumentation, survey strategies, scientific discoveries, and enduring impact on SETI, time-domain
radio astronomy, and the preservation of historical astronomical data. Despite its scientific significance, most of the data collected by the Ohio SETI Program remains unexplored, leaving a unique archive available for future research.
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High Energy Physics (Theory)
Supersymmetry of the static Reissner-Nordström black hole in Bertotti-Robinson ($\mathrm{AdS}_2 \times \mathbb{S}^2$)
Andrea Di Pinto and Adriano Viganò
We examine supersymmetry of charged and accelerating black holes embedded in a Bertotti-Robinson universe, in the context of $N=2$, $D=4$ supergravity. After a review of the solution, we study the constraints that guarantee supersymmetry and explicitly compute the Killing spinors of the spacetime. We show that the supersymmetric solution saturates the BPS bound, and we use this result to compute the mass of the black hole and to analyze the thermodynamics of the solution. Finally, we present a generalization of the extremal solution to include the cosmological constant.
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Chemical Physics · Cross-listed from math.OC
The Fuel Optimizer: A Data-Driven Numerical Framework for Formulation of Aviation Turbine Fuel
Ana Larrañaga, Steven L. Brunton, Jacobo Porteiro et al. (+1 more)
The Fuel Optimizer is an inverse design framework for sustainable aviation fuels that starts from a user-defined merit function and identifies the optimal combination of chemical species or hydrocarbon families that optimize a combination of targets. As a case study, a database of fuel blends meeting selected property standards was simulated in a reactor model to obtain pollutant emissions at cruise conditions. A surrogate model was developed to reduce the computational cost of evaluating candidate blends, taking fuel composition as input and predicting emissions as output. A genetic
algorithm was used to optimize fuel formulation according to two merit functions designed to break the nitrogen
oxides - CO trade-off, and minimize pollutant emissions over the landing-and-take-off cycle. Constraints included selected property standards (including seal swelling) and composition limits. Fuel candidates from the framework outperformed the training database across all merit functions, and the optimal candidates were validated through reactor simulations.
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All authors Ana Larrañaga, Steven L. Brunton, Jacobo Porteiro, Dario Lopez-Pintor
Instrumentation and Methods for Astrophysics
A data-driven method for measuring corner-clipping probabilities in segmented particle detectors
Joaquín de Jesús, Juan Manuel Figueira, Federico Sánchez et al. (+1 more)
The accuracy of particle counting in highly segmented detectors is limited by the corner-clipping effect, in which a single ionizing particle generates signals in adjacent detection elements. This phenomenon introduces a direction-dependent overcounting bias that distorts reconstructed observables and is commonly corrected using Monte-Carlo simulations, thereby inheriting modeling uncertainties. We present a fully data-driven method to directly measure the single-particle corner-clipping probability, exploiting the nanosecond timing resolution of modern detectors to statistically distinguish genuine corner-clipping events from random coincidences, with non-neighboring detection elements serving as an intrinsic control sample. The technique is validated using detailed simulations of the Underground
Muon Detector of the Pierre Auger Observatory, reproducing the true angular dependence of the corner-clipping probability with absolute deviations below 0.01. To parameterize the results, we introduce a compact analytical model incorporating detector geometry, minimum detectable path length, and orientation-independent contributions. The proposed methodology and parameterization enable the direct incorporation of data-driven corner-clipping corrections into reconstruction
algorithms, mitigating the overcounting bias and ultimately yielding a more accurate determination of the muonic component of extensive air showers. These developments are broadly applicable to any segmented detector with sufficient timing resolution, making them relevant to a wide range of experiments in high-energy and astroparticle physics.
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All authors Joaquín de Jesús, Juan Manuel Figueira, Federico Sánchez, Darko Veberič
Strongly Correlated Electrons
Yang Yu, Gaurav Harsha, Lei Zhang et al. (+4 more)
Quantum impurity models, which describe the coupling between interacting orbitals and a non-interacting bath, play a central role in the physics of strongly correlated electron systems. Solving a
quantum impurity model in general requires the use of non-perturbative numerical methods.
Hamiltonian-based approaches, which rely on an explicit bath discretization, are typically limited to a small number of bath sites or small
entanglement, and diagrammatic methods suffer from sign problems, slow convergence, or diagram truncation approximations. Here we show that these two classes of methods can be combined: augmenting diagrammatic methods with a small auxiliary bath can reduce the residual problem to a regime where low-order perturbation theory is highly accurate and rapidly converging. In a simple
benchmark, the precision of the hybrid approach surpasses bold-line calculations by several orders of magnitude; for a strongly interacting two-orbital model with a severe sign problem, convergence is achieved at three orders of magnitude lower computational cost than competing methods; and convergence to the unknown exact result is rapidly accelerated in a difficult realistic problem. Our results establish a practical route to high-precision
quantum impurity solutions in correlated
quantum systems.
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All authors Yang Yu, Gaurav Harsha, Lei Zhang, Agnieszka Jażdżewska, Dominika Zgid, Xinyang Dong, Emanuel Gull
Astrophysics of Galaxies
MusE GAs FLOw and Wind (MEGAFLOW) XIV: Background-Galaxy Absorption Reveals Kiloparsec-Scale Structure in the Cool Circumgalactic Medium
Yucheng Guo, Nicolas F. Bouché, Martin Wendt et al. (+9 more)
The properties of the cool ($T\sim10^4$~K) gas in the circumgalactic medium (CGM) are closely linked to the physical mechanisms that create and maintain this multiphase medium. The cool CGM is thought to consist of discrete clouds, whose characteristic size is unknown. Here we present a
geometric and direct approach to constrain the coherence scale of these cool structures using stacked MgII absorption lines measured against extended background
galaxies and effectively point-like background
quasars, whose sizes are a few kpc and $\lesssim 0.01$pc, respectively. When the background-source size is smaller than the coherence scale of the foreground clouds, incomplete covering lowers the detection fraction and causes the median stacked absorption to differ from the mean. For stacked MgII absorption against background
galaxies, the mean and median equivalent width (EW) profiles are broadly consistent. For stacked MgII absorption against background
quasars, by contrast, the median and mean EW profiles differ significantly, reaching a $\approx10\sigma$ difference beyond 100 kpc. Furthermore, we find that the median and mean EW profiles are broadly consistent for large background
galaxies (median half-light radius $\approx 6.6$ kpc), but differ at the $\approx3\sigma$ level for small background
galaxies ($\approx 1.5$ kpc). This suggests that the MgII-bearing gas has an effective transverse coherence scale of order a few kiloparsecs, broadly consistent with the $\sim$2–7 kpc range probed by the background
galaxies. Using a toy model in which the CGM is populated with discrete cool clouds, we show that the observed differences arise naturally from the combination of partial covering and beam averaging. Our results provide a new geometry-based measure of the small-scale structure of cool CGM gas.
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All authors Yucheng Guo, Nicolas F. Bouché, Martin Wendt, Timothy Heckman, Joop Schaye, Sanchayeeta Borthakur, Johannes Zabl, Maxime Cherrey, Sowgat Muzahid, Ismael Pessa, Ramona Augustin, Daria Kozlova
Astrophysics of Galaxies
High-Resolution ALMA Imaging for a Gravitationally-lensed Quasar at $z=6.5$: Constraining the AGN Contribution to Galactic-Scale Dust Heating
Minghao Yue, Xiaohui Fan, Anna-Christina Eilers et al. (+6 more)
We present high-resolution (beam size $0\farcs076\times0\farcs040$) Atacama Large Millimeter/submillimeter Array (ALMA) observations of the far-infrared $(\lambda_\text{rest}=162.7\mu\rm{m})$
dust continuum of J0439+1634, a gravitationally lensed
quasar at $z=6.52$. We perform pixelated lens modeling for the visibility data, finding that J0439+1634 is well-described by a singular isothermal ellipsoid plus an external shear
lensing model. The best-fit
lensing potential exhibits a naked-cusp configuration, confirming the finding in Fan et al. (2019). The reconstructed source plane continuum emission shows a compact bright core, with size $\lesssim200$ pc and peak brightness $\sim0.6 \text{ Jy arcsec}^{-2}$. The total continuum flux at 245 GHz is $3.36\pm0.02$ mJy. The flux magnification is {$4.63\pm0.03$}, indicating an average source-plane resolution of $0\farcs019$ (equivalent to 104 pc). The spatial resolution around the supermassive black hole reaches $\sim36$ pc. %Using the new
lensing model, we re-fit the Hubble Space
Telescope image for J0439+1634, and find that the position of the optical
quasar is consistent with the brightest pixel in the
dust continuum map. Leveraging the exceptional source-plane resolution, we build a radiative transfer model to describe the observed
dust emission profile. The best-fit model indicates that heated
dust from the active
galactic nucleus (AGN) dominates the sub-millimeter emission at $r\lesssim100$ pc and that
star-heated
dust dominates the outer region of the host
galaxy. AGN heating contributes {$\sim13\%$} to the observed sub-mm flux. Therefore, previous far-infrared-based
star formation rate measurements for most high-
redshift quasars are likely mildly overestimated.
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All authors Minghao Yue, Xiaohui Fan, Anna-Christina Eilers, Jinyi Yang, Feige Wang, Jianwei Lyu, James W. Nightingale, Ann Zabludoff, Ran Wang
High Energy Physics (Phenomenology)
Matrix element method at NLO: A fine proof of concept in POWHEG
Ulrich Haisch, Jakob Linder, Luc Schnell et al. (+2 more)
The
matrix element method (MEM) provides a fully probabilistic approach to confront experimental events with theory, retaining all correlations in the scattering
matrix element. While leading-order MEM is widely used and automated, extending it to next-to-leading order (NLO) in QCD is challenging due to infrared divergences, negative weights, extra final-state partons, and multi-dimensional phase-space integration. We demonstrate that the POWHEG method offers a practical path to MEM at NLO accuracy. By projecting real-emission events onto Born kinematics via the mappings inherited from the $\tilde{B} (\Phi)$ function, our method consistently includes the hardest QCD radiation while preserving the NLO-accurate normalization. As a proof of concept, we apply the method to fully leptonic $W^+W^-$ production in the Standard Model effective field theory (SMEFT), considering a CP-even dimension-six triple-gauge-
boson operator. At the parton level, the resulting NLO MEM exploits
spin and polarization correlations in the final-state
lepton kinematics, yielding enhanced discrimination between the SM and BSM hypotheses compared with conventional cut-and-count observables. Our results demonstrate the feasibility of incorporating NLO QCD corrections into the MEM and establish a framework for future applications to a broad range of
collider processes.
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All authors Ulrich Haisch, Jakob Linder, Luc Schnell, Marius Wiesemann, Giulia Zanderighi
Soft Condensed Matter
How to grow a straight filament
Ludwig A. Hoffmann and L. Mahadevan
How can a growing biological filament remain straight despite
stochastic fluctuations in growth? Motivated by filamentary structures that develop reproducibly across biological systems, we study the stability of a noisy, growing elastic filament regulated by feedback. We formulate a minimal model in which growth responds to the filament's strain,
curvature, and orientation through local or nonlocal spatiotemporal feedback laws. Linear stability analysis identifies the conditions under which these feedback mechanisms stabilize a straight configuration. In the presence of noise, we show that purely local feedback requires orientation sensing to suppress long-wavelength instabilities, whereas nonlocal feedback allows stabilization through proprioceptive (
curvature) sensing alone. Coupling to an elastic substrate further suppresses large-scale fluctuations. Our results establish minimal control strategies that ensure robust straight growth and suggest experimental signatures for identifying the feedback mechanisms underlying morphogenesis.
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High Energy Physics (Phenomenology)
Multiplicity-dependent forward jet production in proton-nucleus collisions
Lei Wang
Forward jet production in
proton–
nucleus collisions probes a dilute projectile scattering from a dense small-$x$
nuclear gluon field, while the charged-particle multiplicity inside the jet probes the final-state cascade in the jet cone. We develop a factorization framework for single-inclusive forward jets with an internal multiplicity measurement by combining the Color Glass Condensate (CGC) description of the production process with soft-collinear effective theory (SCET) semi-inclusive jet functions. The construction preserves the inclusive limit exactly: at zero multiplicity weight it reduces to the known inclusive next-to-leading order (NLO)/resummed CGC forward-jet cross section. We define the multiplicity-measured jet operator in a CGC background, formulate the matching that separates PDF, BK/JIMWLK, Sudakov, SiJF, and multiplicity-
evolution radiation, and identify the Wilson-line resolution mechanism through which saturation can modify the internal multiplicity
evolution. The resulting framework shows that high-multiplicity forward jets are sensitive both to the
quark/
gluon mixture generated by the CGC production kernel and to finite-$Q_s$ corrections when an early in-cone splitting is resolved by the target. A baseline numerical implementation validates the factorized structure and illustrates the resulting multiplicity-conditioned
nuclear modification.
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Quantum Physics · Cross-listed from cs.AR
Coset Ensemble Decoder for Quantum Error Correction with Algorithm-Hardware Co-Design
Shuang Liang, Jubo Xu, Giulio Bassanino et al. (+8 more)
Reliable large-scale
quantum computation relies on fault-tolerant architectures, where
quantum error correction (QEC) continuously extracts and decodes error syndromes in real time. A critical component in QEC is the decoder, a classical subsystem that must simultaneously deliver high logical accuracy and ultra-low latency. This paper presents a novel
algorithm-hardware co-design that improves the accuracy-latency trade-off over existing approaches such as vanilla Minimum-Weight Perfect Matching (MWPM) and Union-Find (UF) decoders. At the algorithmic level, we introduce coset ensemble decoding, which improves UF decoding by explicitly exploiting logically equivalent cosets. Our method performs ensemble forest exploration to generate multiple coset-consistent candidates and aggregates them to approximate coset-level maximum-likelihood decoding. We further reduce computational and
memory complexity via reverse-order elimination and lossless graph compression, without sacrificing accuracy. At the hardware level, we design a domain-specific architecture that temporally reuses resources, avoiding the code-distance-proportional resource growth in prior spatial architectures. Several optimizations, such as multi-bank
memory hashing and hierarchical ID mapping, are proposed to mitigate pipeline stalls and
memory conflicts under highly concurrent access patterns. Under a
circuit-level depolarizing noise model, our co-design approach achieves a better accuracy-latency trade-off than prior MWPM- and UF-based decoders, while reducing FPGA LUT consumption by up to 8.2 times compared with reported UF-based decoder resources. The tunable candidate number further exposes a flexible design knob, enabling users to tailor decoding performance to the requirements of different fault-tolerant workloads. Our implementation is publicly available at https://github.com/IMSeonL/coset-ensemble-decoder.
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All authors Shuang Liang, Jubo Xu, Giulio Bassanino, Qianzhou Wang, Yidong Zhou, Yuncheng Lu, Zhiwen Mo, Paul H. J. Kelly, Bo Yuan, Wayne Luk, Hongxiang Fan
Materials Science
Approaching the Limit of Intrinsic Crystalline Thermal Insulation
Ruihuan Cheng, Zhiqiang Cui, Mani Jayaraman et al. (+9 more)
Crystalline materials with ultralow thermal conductivity ($\kappa$) are potential thermal barrier coatings or thermoelectrics, yet the discovery of ultralow-$\kappa$ materials remains inefficient due to the limitations of trial-and-error approaches. Herein, we propose a state-of-the-art high-throughput workflow that integrates universal machine learning interatomic potentials with high-fidelity
phonon transport theories to accelerate the exploration of thermal
insulators. Applying this approach, we identify dozens of crystalline materials with intrinsic room-temperature $\kappa$ values below 0.2 $\rm W m^{-1} K^{-1}$. Among them, we report and experimentally validate CsTlI$_4$, a record-breaking material with an ultralow $\kappa$ of 0.14 $\rm W m^{-1} K^{-1}$ at 300 K. Structural and bond analyses reveal that a hierarchical bonding framework, consisting of multi-coordinated Cs-I and antibonding Tl-I interactions, leads to weak chemical bonding and a soft
lattice. These features reduce
phonon group velocities, enhance
phonon scattering, and induce strong vibrational mismatch between sublattices, collectively suppressing both particle-like
phonon propagation and wave-like tunneling. Beyond this specific system, we establish physically interpretable descriptors based on interatomic force constants that correlate strongly with ultralow $\kappa$ and capture the role of bonding hierarchy and coordination environments in governing thermal transport. This work demonstrates a robust data-driven strategy for accelerating the discovery of thermal
insulators and provides microscopic insight into how hierarchical bonding and strong anharmonicity cooperate to impede heat-carrying vibrations.
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All authors Ruihuan Cheng, Zhiqiang Cui, Mani Jayaraman, Lincong Ji, Chen Wang, Zesheng Zeng, Petr Levinsky, Jiri Hejtmanek, Christophe Candolfi, Emmanuel Guilmeau, Xingchen Shen, Yue Chen
Medical Physics
Range of Normalized Glandular Dose for Mammography Using Patient-Specific Glandular Fractions
Lacey L. Medlock, Murtuza S Taqi, Bryce Smith et al. (+1 more)
Breast cancer is the most common cancer among women, and mammography remains the primary modality for early detection. Because mammography uses ionizing radiation, accurate estimation of normalized glandular dose (DgN) is important for risk assessment. Recent breast dosimetry models, including TG-282, incorporate population-based glandular tissue distributions; however, patient-specific glandular distributions remain unknown from conventional mammographic projections. In previous work (Smith, Dey et al., 2025), glandular fraction (GF) maps were estimated from a single mammographic projection. While these maps determine glandular path length along each projection ray, they do not uniquely define glandular tissue depth. In this work, we propose a framework for estimating a patient-specific range of DgN from a projection-derived GF map. Using simulated data, glandular tissue was distributed to the top, center, and bottom of the breast volume using Siddon ray-tracing. These configurations preserved the GF map while producing maximum, intermediate, and minimum DgN values. Monte Carlo simulations were performed, and DgN was normalized to entrance air kerma. DgN varied by up to a factor of three solely due to differences in glandular tissue depth, despite identical GF maps and visually indistinguishable projection images. Using randomized realizations derived from TG-282 glandular distributions for Cranio-Caudal (CC) and Medio-Lateral Oblique (MLO) views, dose ratios were calculated relative to central glandular placement. Central placement overestimated DgN by less than 5 and 15 percent on average for MLO and CC distributions respectively, whereas centroid-based placement underestimated dose by up to 25 percent. These results indicate that patient-specific bounds on DgN can be estimated from limited mammographic information and that central placement provides a conservative dose estimate.
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All authors Lacey L. Medlock, Murtuza S Taqi, Bryce Smith, Joyoni Dey
Chemical Physics
The UZH protocol: Separating errors and constructing improved CP2K basis sets and pseudopotentials
Hossein Mirhosseini, Tiziano M. A. Müller, Matthias Krack et al. (+2 more)
Reliable density-functional simulations require numerical settings whose residual errors are smaller than the chemical and materials trends being interpreted. In CP2K/Quickstep, this requirement is complicated by the joint use of atom-centered Gaussian basis sets and norm-conserving pseudopotentials: a code-to-code discrepancy usually contains both contributions. We present the UZH protocol, a closed-loop CP2K workflow that calibrates molecularly optimized Gaussian basis sets on small molecules, validates the resulting settings in unary-
crystal equation-of-state
benchmarks, identifies whether the limiting approximation is the Gaussian basis or the pseudopotential. The diagnosis is then used to revise the parameter files. The central diagnostic is a three-way comparison between production CP2K-GTH-UZH calculations, SIRIUS calculations using the same Goedecker–Teter–Hutter pseudopotential in a systematic plane-wave representation, and all-electron full-potential linearized augmented-plane-wave SIRIUS references. This construction decomposes the practical CP2K error into a Gaussian-basis component and a pseudopotential component. The protocol distinguishes basis-limited noble-gas and heavy-element cases from pseudopotential-limited transition-metal cases, guides targeted revisions with the CP2K basis and pseudopotential optimizers, and produces improved MOLOPT basis sets and GTH pseudopotentials as explicit outputs of the workflow. The UZH protocol is therefore constructive: it does not merely measure or reduce errors a posteriori, but allows turning verification outliers into validated CP2K parameter files for simulations across molecules and condensed phases.
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All authors Hossein Mirhosseini, Tiziano M. A. Müller, Matthias Krack, Thomas D. Kühne, Jürg Hutter
General Relativity and Quantum Cosmology
A Friendly Phantom: Late-time AdS-to-dS transition and cosmological tensions
Özgür Akarsu, Leandros Perivolaropoulos, A. Emrah Yükselci et al. (+1 more)
We present Ph-$\Lambda_{\rm s}$CDM, a phantom-scalar realization within General Relativity of the sign-switching cosmological-constant idea, $\Lambda_{\rm s}$CDM, in which a phantom scalar evolving on a bounded
hyperbolic-tangent potential induces a smooth mirror AdS-to-dS transition in the late-time dark-energy density. The wrong-sign kinetic term, usually viewed as pathological, becomes the mechanism lifting the field from a negative- to a positive-energy
vacuum-like regime. The construction also shows that the field can become repulsive while its energy density is still negative. The cosmology nevertheless remains controlled: total energy stays positive, the late-time attractor is de Sitter rather than a Big Rip, and the dynamics remain safely infrared. Ph-$\Lambda_{\rm s}$CDM thus offers a concrete late-time mechanism with the potential to address multiple cosmological tensions.
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All authors Özgür Akarsu, Leandros Perivolaropoulos, A. Emrah Yükselci, Alexander Zhuk
High Energy Physics (Phenomenology)
Endpoint Logarithms in the NLO Mueller-Navelet Jet Vertex: Threshold Matching and BLM/MOM Prescription Sensitivity
Lei Wang
The endpoint region $\zeta\to1$ of the NLO forward jet vertex has not been systematically separated from BFKL energy-scale terms in Mueller-Navelet phenomenology. Starting from the small-cone NLO vertex, we isolate the
quark and
gluon plus distributions and construct a BFKL-aware threshold matching scheme that preserves exact NLO accuracy. The conservative Scheme-II exponent resums only the ordinary endpoint logarithms and leaves the $\chi(n,\gamma)\ln\bar N$ term in the fixed-order coefficient, avoiding an uncontrolled tower of mixed endpoint-BFKL logarithms. In fixed-baseline CMS tests, this matched vertex is a controlled deformation of an optimized-NLL pointwise BLM/MOM calculation: it moves $R_{21}=C_2/C_1$ in the high-$\Delta Y$ direction favored by CMS, but it does not improve $C_1/C_0$ or $R_{32}=C_3/C_2$ in the same prescription. A coefficient-projected table-BLM diagnostic improves the absolute moments but lowers $R_{21}$ and is sensitive to the large-$|\nu|$ tail. Thus the endpoint matching is internally consistent and phenomenologically informative, while the present setup does not provide a simultaneous description of all five CMS azimuthal observables.
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Mesoscale and Nanoscale Physics
Interplay between photon condensation and electron-electron interactions in molecular systems
Matteo Parisi, Elisabetta Paladino, Giuseppe A. Falci et al. (+4 more)
We investigate a minimal molecular model consisting of square planar plaquettes hosting multiple electrons, whose dynamics is governed by a tight-binding
Hamiltonian supplemented by on-site Hubbard repulsion. By coupling this system to a spatially nonuniform cavity mode, we analyze the emergence of a magnetostatic instability, namely
photon condensation, originating from the paramagnetic Van Vleck mechanism. The global behavior of the system is analyzed for different electronic filling factors, and we find that, except for the special cases of half-filling and a single electron, where the transition, if it occurs, is necessarily a second-order phase transition, the global system may also undergo a first-order transition because of the action of the electron-electron interaction. The polaritonic excitation energies are analyzed, providing clear spectroscopic signatures of the magnetostatic instability and of its order
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All authors Matteo Parisi, Elisabetta Paladino, Giuseppe A. Falci, Gian Marcello Andolina, Salvatore Savasta, Marco Polini, Francesco M. D. Pellegrino