High Energy Physics (Phenomenology)
Commensurate Structure of Quark and Lepton Mixing: Eighteenth Powers of One Parameter and a Digital-Clock Quantization of the Unitarity Triangles
Vernon Barger
We identify two commensurate structures in the measured
quark and
lepton mixing data, one multiplicative and one angular, and their exact relation. With the hierarchy parameter $\varepsilon\equiv|V_{ub}|^{3/10}=0.1869\pm0.0018$, the measured Fritzsch–Xing (FX) angles satisfy $\sin\theta_u=\varepsilon^{26/18}$, $\sin\theta_d=\varepsilon^{17/18}$, and $\sin\theta=\varepsilon^{34/18}$ with coefficients within $2.5\%$ of unity, and the phase is maximal, $\phi_{\rm FX}=92.3^\circ\pm2.7^\circ$ against $\pi/2$. Unit coefficients reproduce the remaining
moduli at the percent level and fix the derived Jarlskog invariant, $J=\varepsilon^{111/18}\sin\phi_{\rm FX}$, matching the measured $3.08(14)\times10^{-5}$. The rephasing-invariant image of this structure is a unitarity triangle quantized on the $\pi/24$
lattice, a digital clock, $(\alpha,\beta,\gamma)=(12,3,9)\times7.5^\circ$, consistent with data at $1\sigma$ through $\alpha\simeq\phi_{\rm FX}$ and the
theorem $\tan\beta\simeq\sqrt{\varepsilon}$; degree-level $\gamma$ confronts $67.5^\circ$–$68^\circ$. For the
leptons, where only the angular structure can act, its PMNS analog, formed from columns $1$ and $3$, free of Majorana phases, on the same
lattice requires $\delta_{\rm CP}\simeq296^\circ$ in the upper octant or $244^\circ$ in the lower, testable at DUNE and Hyper-Kamiokande. The
quark and
lepton triangles share $\beta=22.5^\circ$, measured for
quarks, predicted for
leptons, and differ by a transfer of two
lattice units, with corollary $\delta_{\rm CP}\simeq-\delta\simeq295^\circ$. The same $\varepsilon$ sets the
neutrino mass ratio, $r\equiv m_2/m_3=\varepsilon^{19/18}$, and the PMNS first row follows in powers of $r$, $(r^{1/9},\,r^{1/3},\,\tfrac{\sqrt{3}}{2}r)$, both relations at $0.2\sigma$ and testable at JUNO. The analysis is confined to the parameterization level; no dynamics is assumed.
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Astrophysics of Galaxies
Antimatter in the universe and Milky Way
A.D. Dolgov
Theoretical model leading to a significant
Galaxy population by
primordial antimatter is described. Observational data confirming this "crazy" prediction are presented.
Mesoscale and Nanoscale Physics
Nanoscale imaging of ferromagnetic vortex dynamics with scanning NV magnetometry
Jeffrey Rable, Jyotirmay Dwivedi, Nitin Samarth et al. (+3 more)
The generation and manipulation of
spin waves at the nanoscale via
magnetic vortices are of considerable importance because of their broad applications across magnonic and
quantum technologies. Previously, fixed nitrogen-vacancy (NV) centers in diamond have been used to locally characterize
vortex dynamics, and scanning NV magnetometry (SNVM) has been used to image
vortices' static stray fields. Here, we demonstrate SNVM imaging of both the static and microwave fields generated by
vortices in mesoscopic permalloy structures with $\sim$50 nm spatial resolution, achieving excellent agreement with micromagnetic simulations, while revealing the effects of disorder. We further demonstrate a 40$\times$ microwave field enhancement near a
vortex core and image the disorder-dependent, spatially varying, evanescent decay of these microwaves. Our ambient, tabletop technique surpasses diffraction-limited techniques' resolutions by at least 5$\times$, with far greater accessibility and throughput than synchrotron radiation-based techniques, offering new opportunities in the study and development of magnonic devices.
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All authors Jeffrey Rable, Jyotirmay Dwivedi, Nitin Samarth, Paul Stevenson, Arun Bansil, Swastik Kar
Fluid Dynamics
Wind-Informed Rapid Flight-Planning in Complex Urban Topologies via Machine Learning and Experimental Validation
Peter I. Renn, Alejandro A. Stefan-Zavala, Julian Humml et al. (+8 more)
Advanced air mobility operations hold the potential to enhance and expand regional transportation of both people and goods in populated areas. However, hazardous flight conditions arising from interactions between wind and the built environment remain a significant challenge for aerial vehicles in urban settings. This work proposes a novel framework towards safe flight planning of aerial vehicles in windy urban environments. A learning-based surrogate model is trained to rapidly predict flow fields from readily available information such as building geometry and incident wind. This surrogate prediction is used to calculate a volumetric flight challenge scalar field based on critical flow parameters and proximity to structures. A safe, flow-informed flight trajectory is then identified through a cost-minimizing pathfinder. The complete system is demonstrated experimentally through flight tests of a micro aerial vehicle through a model urban geometry placed in a large fan-array wind tunnel. Comparing this approach to trajectories generated without knowledge of the wind field, we find the flow-informed approach reduces undesired vehicle displacement and improves flight stability. This work is among the first practical demonstrations of safe, wind-aware methodologies for advanced air mobility in urban environments.
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All authors Peter I. Renn, Alejandro A. Stefan-Zavala, Julian Humml, Sabera Talukder, Aysha AlMazrouei, Kresna Aji, Debashisha Mishra, Emanuele Panizio, Jennifer Simonjan, Yisong Yue, Morteza Gharib
Quantum Physics
Programmable Heisenberg-limit sensor from a nonlinear quantum energy pump
Yang Peng
We introduce a programmable Heisenberg-limited bosonic
quantum sensor based on a nonlinear
quantum energy pump, implemented with a Kerr-nonlinear resonator coupled to multiple high-Q microwave terminal resonators. For parameter estimation encoded in an arbitrary number-conserving
Hamiltonian acting on the terminal modes, we analytically construct optimal sensing protocols that attain the maximal
quantum Fisher information, including initial-state loading, probe preparation, and readout. For diagonal multiparameter signals, we further show that the full phase-sensing
quantum Fisher information
matrix can be obtained from correlations of locally measured physical terminal works, providing a signal-free calibration of the metrological resource. We numerically demonstrate the construction and its robustness using realistic
circuit-QED parameters while including experimentally relevant imperfections.
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Instrumentation and Methods for Astrophysics
Closed-loop Atmospheric Dispersion Correction for High-Contrast Imaging with MagAO-X
Katie Twitchell, Sebastiaan Haffert, Jared R. Males et al. (+17 more)
Incoming starlight is refracted as it enters Earth's atmosphere from the
vacuum of space. The wavelength-dependence of atmospheric refraction causes elongation of the broadband PSF of ground-based
telescopes, especially in the visible spectrum. The result is degraded image quality alongside reduced coronagraph light-blocking efficiency, both of which limit high-contrast observations. An atmospheric dispersion corrector (ADC) is a dispersive optic used to compensate for this effect. Current methods for dispersion compensation use analytical models to anticipate dispersion strength based on parameters such as site altitude and
telescope zenith angle; however, dispersion strength is also dictated by a number of factors that cannot be measured, including instantaneous humidity, temperature, and pressure along the line of sight to the
star. This leads to constant over- or under-correction of the true atmospheric dispersion by the ADC. In this work, we use the Magellan extreme adaptive optics system MagAO-X at Las Campanas Observatory to measure and correct residual atmospheric dispersion in real-time. The amount of residual dispersion is encoded in the orientation of satellite spots generated by using MagAO-X's deformable mirror as a diffraction grating. We have used these real-time measurements as feedback for closed-loop control of the ADCs on-sky at visible and NIR wavelengths, reducing residual atmospheric dispersion down to sub-mas/$\mu$m levels. Active atmospheric dispersion correction on MagAO-X is a precursor to high-contrast imaging with Extreme AO for the upcoming Extremely Large
Telescopes, where high-precision dispersion compensation will be required to image
exoplanets in reflected light.
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All authors Katie Twitchell, Sebastiaan Haffert, Jared R. Males, Laird M. Close, Olivier Guyon, Kyle Van Gorkom, Alexander Hedglen, Parker T. Johnson, Maggie Y. Kautz, Jay K. Kueny, Joshua Liberman, Miles Lucas, Avalon McLeod, Matthijs Mars, Eden A. McEwen, Jialin Li, Joseph D. Long, Jhen Lumbres, Lauren Schatz, Elena Tonucci
Astrophysics of Galaxies
Scaling Relations of Galactic Outflows Across Cosmic Time: New Insights from Cosmic Noon
Tiffany Liou, Xinfeng Xu, Allison L. Strom et al. (+8 more)
Galactic outflows play a significant role in regulating
galaxy evolution. Scaling relations between
stellar mass ($M_\ast$),
star formation (SFR), and
outflow properties have been extensively studied at low
redshifts ($z<1$) but less so beyond $z \sim 2$. We construct a joint sample of 387
galaxies from $z \sim$ 0-9, including 98 new
Cosmic Noon
galaxies from the Keck Baryonic Structure Survey and the Keck Lyman Continuum Spectroscopic Survey. Using high signal-to-noise emission lines (SNR $>$ 50 for H$\alpha$ or [OIII] $\lambda5007$) from Keck/MOSFIRE spectra, we detect warm-ionized
outflows by decomposing lines into narrow and broad components. With the joint sample, we explore the
redshift evolution of
outflow scaling relations. On average,
outflows at
Cosmic Noon have higher maximum velocities than those at low$-z$ by up to a factor of 3 for a fixed $M_\ast$, SFR, or SFR surface density. They also have higher mass
outflow rates for a fixed $M_\ast$. Despite faster and stronger
outflows, there is no
evolution in the mass loading factor for a fixed $M_\ast$. We find evidence for
galactic fountains, as the majority of outflowing gas is recycled at a radius of $\sim$0.03 R$_\textrm{vir}$. We also constrain the overall
outflow occurrence rate in our
galaxy sample to be at least 30$\%$ when taking
galaxy orientation and
outflow geometry into account. By analyzing the largest sample of warm-ionized
outflows at
Cosmic Noon to date and compiling large
galaxy samples across all
redshifts, we present a comprehensive analysis of
galactic outflows throughout
cosmic time.
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All authors Tiffany Liou, Xinfeng Xu, Allison L. Strom, Nathalie A. Korhonen Cuestas, Claude-André Faucher-Giguère, Tim B. Miller, Gwen Rudie, Ryan F. Trainor, Naveen A. Reddy, Charles C. Steidel, Yuguang Chen
Optics
What should a linear optical frontend compute? Assessing the role of meta-optics, nonlocality, and coherence in hybrid inference systems
Nicholas Behrens, Yandong Li and Francesco Monticone
Hybrid inference systems that pair an optical frontend with a digital backend offer a route to offload computation to the physical layer. Yet what the optics should compute, and when this is beneficial, has remained unclear. Here, we show that, for classification tasks, a well-designed optical frontend reshapes the statistics of the sensor intensity readout to improve class separability, quantified by the Bhattacharyya distance. This training-free metric predicts downstream accuracy and reveals that much of the discriminative information resides in inter-pixel correlations. We then identify the roles of coherence and different forms of nonlocality. Because the sensor measures intensity, a linear frontend produces features that are quadratic in the input field; however, only nonlocal, coherent optical systems can exploit the associated information. Such systems can yield significant performance gains, surpassing the best trained linear preprocessor. These results provide physical insights and new design principles for optimal optical–electronic inference systems.
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Fluid Dynamics
SA-AI (Spalart-Allmaras with Autogenous Inception) Technical Summary
Qiqi Wang
Natural transition from laminar to turbulent flow can be modeled by using only the Spalart-Allmaras (SA) working variable. The variable serves as its own transition indicator, in a one-equation Reynolds-averaged Navier-Stokes (RANS) closure. Its sub-O(1) range is dynamically inert in the baseline model. That range becomes a Tollmien-Schlichting amplification factor. A blended production term then drives the SA transport equation through laminar instability growth and turbulent eddy-viscosity production. Computations with this formulation on a zero-pressure-gradient flat plate, the NLF(1)-0416 and Eppler 387 airfoils, a two-element section, a circular cylinder through the drag crisis, the Daedalus human-powered-aircraft wing, and a 6:1 prolate spheroid are compared with experimental data and with other transition models.
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Instrumentation and Methods for Astrophysics
windsoCC: reconstructing the wind-driven halo in MagAO-X images using wavefront sensor telemetry
Jay K. Kueny, Jared R. Males, Alycia J. Weinberger et al. (+16 more)
The wind-driven
halo (WDH) is a persistent, low spatial frequency noise artifact that arises due to the servo-lag error inherent to all adaptive optics (AO) instruments. Spatial filtering may be employed to overcome this artifact, however, filtering out the WDH while simultaneously preserving signal from an extended astrophysical object of interest is exceptionally challenging. Additionally, since the WDH changes in intensity and position angle through an observation, data-driven
algorithms (e.g., KLIP) that are commonly used to subtract the starlight need to be overly-aggressive to remove both the static and dynamic noise components. Since wavefront sensors (WFSs) continuously track the closed-loop residual wavefront error, WFS telemetry presents the ideal resource for combating this type of noise artifact through postprocessing. Using archival WFS telemetry from MagAO-X, which is the “extreme" AO instrument for the 6.5-meter Magellan-Clay
telescope, we demonstrate a novel workflow for WDH reconstruction and removal in individual coronagraphic science images. MagAO-X is equipped with a pyramid WFS capable of recording wavefront telemetry at a high-cadence which is saved during data acquisition. Given this, we detail how our WFS data processing pipeline, windsoCC, cross-correlates the recorded closed-loop wavefront to measure the wind vectors of several turbulent layers of the atmosphere above Las Campanas Observatory. We then make use of the wind parameters learned through windsoCC to reconstruct the WDH footprint by leveraging a parametric model. Notably, we demonstrate a dramatic improvement in object recovery using on-sky MagAO-X images of the disk around HR~4796A at visible wavelengths.
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All authors Jay K. Kueny, Jared R. Males, Alycia J. Weinberger, Laird M. Close, Joseph D. Long, Joshua Liberman, Sebastiaan Haffert, Eden McEwen, Maggie Y. Kautz, Olivier Guyon, Logan Pearce, Parker T. Johnson, Katie Twitchell, Jialin Li, Alex Hedglen, Avalon Gower, Warren Foster, Jhen Lumbres, Lauren Schatz
High Energy Physics (Phenomenology)
The near-threshold cross section of $e^+e^- \to \Omega^-\bar{\Omega}^+$: Heavy-flavor rescattering and physics-informed deep learning
Sara Rahmani
Recent precision measurements of the $e^+e^- \to \Omega^-\bar{\Omega}^+$ cross section by the BESIII collaboration provide a valuable opportunity to probe complex hadronic rescattering mechanisms. In this work, we investigate a potential structure near the $D_s\bar{D}_s$ threshold using a coupled-channel framework incorporating $\Omega\bar{\Omega}$, $\Xi\bar{\Xi}$, and $D_s\bar{D}_s$ interactions. The driving potentials are derived from effective Lagrangians respecting heavy
quark spin symmetry,
chiral symmetry, and hidden local
symmetry, and the scattering amplitude is unitarized via the on-shell factorization of the Bethe-Salpeter equation. To go beyond local fits and map theoretical uncertainties, we use a two-step machine-learning framework. First, Simulation-Based Inference with a Mixture Density Network maps the global
Bayesian posterior of the effective couplings. Second, to identify the non-perturbative threshold dynamics without the instabilities of traditional root-finding across multiple Riemann sheets, we employ a Cauchy-Riemann Physics-Informed Neural Network (PINN). The network enforces mathematical analyticity, smoothly continuing the real-axis amplitude into the complex energy plane. We isolate a pole at $M = 3.847$ GeV with zero decay width, sitting $89$~MeV below the $D_s^-\bar{D}_s^+$ threshold. The corresponding S-
matrix residues show an overwhelming coupling to the $D_s\bar{D}_s$ channel, indicating that the threshold dynamics are driven by a dynamically generated $D_s^-\bar{D}_s^+$ bound state.
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High Energy Physics (Experiment)
Design of ALPHA Phase I: A Plasma Haloscope for 10–20 GHz Post-Inflation Axions
ALPHA Collaboration: Xiran Bai, Rustam Balafendiev, Sean E. Barrett et al. (+52 more)
The
axion is a well-motivated hypothetical particle capable of resolving both the strong CP problem and the dark matter mystery, with recent post-inflationary cosmological simulations favoring masses above 40 {\mu}eV.
Plasma haloscopes serve as a promising experimental approach to reach theoretically preferred sensitivities in this mass range. ALPHA, hosted at Yale Wright Laboratory, is an international collaboration developing
plasma haloscopes to search for QCD dark matter
axions. In this letter we present the detailed design and sensitivity projection for the first phase of the ALPHA experiment, which will search the mass range from 10 GHz to 20 GHz (~40 {\mu}eV to 80 {\mu}eV). This search will make use of wire-array
plasma resonators to decouple the physical size from the resonant frequency, a limitation typically faced by traditional microwave cavities, allowing broadband sensitivity approaching KSVZ coupling strengths.
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All authors ALPHA Collaboration: Xiran Bai, Rustam Balafendiev, Sean E. Barrett, Eunice Beato, Pavel Belov, Charles D. Brown, Eduardo A. Castro Muñoz, Jan Conrad, Marcel Demarteau, Alex Droster, Joseph Dubois, Jonathan Echevers, Ali Elhadi, Jim Enriquez, Maryam Haytham Esmat, Andrea Gallo Rosso, Eleanor Graham, Chloe Greenstein, Jon E. Gudmundsson, Karsten M. Heeger, Ishaan Iyer, Heather Jackson, Junu Jeong, Michael J. Jewell, Tyler Johnson, Shriram Jois, Gagandeep Kaur, Claire Laffan, K.W. Lehnert, Samantha M. Lewis, Jacob Lindahl, Reina H. Maruyama, Philip Mauskopf, Andrew M. Meyer, Alexander J. Millar, Dylan R. Miller, Hiranya V. Peiris, Jianyang Qi, Elizabeth P. Ruddy, Sharada Sahoo, Denis Sakhno, Michael Sekatchev, Max Silva-Feaver, Shenyang Shi, Aarav M. Sindhwad, Gaganpreet Singh, Sukhman Singh, Danielle H. Speller, Dajie Sun, Noshin Tabassum, Karl van Bibber, Yongqi Wang, Frank Wilczek, Mackenzie Wooten, Sabrina Zacarias
Geophysics
Ground-to-Cable Strain Transfer in Unburied DAS on Earth and the Moon
Simone Probst, Olav Cornelius, Marc Serra Garcia et al. (+2 more)
Distributed acoustic sensing (DAS) cables are typically buried to ensure good coupling and reduce unwanted atmospheric noise. Unburied deployments are attractive for rapid response applications and for missions to the Moon, where burial is impractical. Unburied DAS, however, suffers from degraded signal quality due to poor strain transfer. Here we quantify bending stress relief as a mechanism behind this loss: cable segments suspended between ground contact points accommodate ground strain by bending, so less axial strain reaches the fiber. We derive the strain transfer of such a segment analytically, compare it to numerical models, and validate it on 56 laboratory configurations of different cable types and lengths. The efficiency is governed by a single dimensionless parameter $\Theta$, set by the ratio of the segment's sag to the cable radius. Keeping the loss below 3% requires a sag below about a quarter of the cable radius. The prediction is quasi-static, holding below the fundamental resonance of the segments. The sag is dominated by the
curvature the cable retains from spooling and handling rather than by gravitational sagging, so $\Theta$ has to be measured and not computed from cable specifications. Because the gravitational contribution is small, the criterion applies equally to deployment on the Moon. Lunar
gravity does reduce the friction available to resist slip at the contact points, but a force balance indicates that slip remains unlikely for natural moonquakes.
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All authors Simone Probst, Olav Cornelius, Marc Serra Garcia, Johan O. A. Robertsson, Carly M. Donahue
Mathematical Physics · Cross-listed from math.QA
3-dimensional TQFTs from derived categories of quantum group representations
Cris Negron
For any finite modular tensor category A, we show that the associated derived $\infty$-category D(A) supports a topological
quantum field theory in dimension 3. This TQFT takes the form of a symmetric monoidal functor from an $\infty$-category of surfaces with markings by objects in D(A), and appropriately decorated bordisms, to the $\infty$-category of dg vector spaces. We show that the state spaces in this theory are naturally identified with linearized mapping spaces for D(A). Though our TQFT requires markings from the derived $\infty$-category, we show that all markings can be removed after taking a homotopy truncation. The resulting unmarked TQFT produces projective mapping class group actions on
cohomology in dimension 2, and in particular a projective SL_2(Z)-action on Hochschild
cohomology. We expect these mapping class group actions to recover those of Lentner et al. arxiv:2003.06527 and Schweigert-Woike arxiv:2004.14343. In dimension 3 we obtain power-series valued
knot invariants, and power-series valued invariants for modular tensor categories. We also obtain power-series invariants for closed 3-
manifold, though these can already be calculated at the abelian level. Our derived field theories are proposed as mathematical formalizations for topological A-twists of certain N=4 supersymmetric QFTs, in dimension 3. Following physical principles, we discuss the possibility of deforming our TQFTs along local systems via an analogous (conjectural) deformation of
quantum group representations along the Langlands dual group.
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Instrumentation and Methods for Astrophysics
Lunar Reflective Interferometry
Peter W. Gorham, T. Joseph W. Lazio, Andrew Romero-Wolf et al. (+14 more)
We present the method of lunar reflection interferometry (LRI) in which a virtual interferometer can be formed by using a spacecraft-borne
antenna in lunar orbit that receives both direct rays and those reflected from the lunar surface. The technique exploits the method of images and is akin to the classic "sea cliff" interferometer, with the Moon's surface, primarily the lunar Maria, replacing the ocean surface. We describe the method in detail, demonstrate that significant portions of the Moon's surface are sufficiently smooth at low
radio frequencies, $\nu \lesssim 10\,\mathrm{MHz}$, for the technique to work, and outline a spacecraft instrument implementation. We describe potential systematic errors and how they could be mitigated. We present several astrophysics applications of the method.
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All authors Peter W. Gorham, T. Joseph W. Lazio, Andrew Romero-Wolf, Patrick S. Allison, Marin M. Anderson, Ali M. Bramson, Roman Burridge, Amy Connolly, Emily S. Costello, Cosmin Deaconu, Susan Lepri, Christian Miki, Eric Oberla, Sean Peters, Kathryn Plant, Julie Rolla, Matthew Siegler
Instrumentation and Detectors
Position Resolution of a Scintillator Hodoscope Employing Triangular Counters with Embedded Wavelength Shifting Fibers
E. Craig Dukes, Ralf Ehrlich, Daniel Lee et al. (+4 more)
Scintillator counters employing embedded wavelength-shifting fibers have been used in particle physics experiments for several decades. Such counters have been produced with square, rectangular, and triangular profiles. An advantage of arrays of triangular counters is that their position resolution can be greatly enhanced by interpolation between adjacent counters using their relative light yields. We report here on a testbeam study of the position resolution of such a scintillator hodoscope and compare the results to a simulation. We find an order of magnitude improvement in the position resolution over that found by simply using the fiber separation.
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All authors E. Craig Dukes, Ralf Ehrlich, Daniel Lee, Luke Watson, Alan Bross, Sten Hansen, Paul Rubinov
Instrumentation and Methods for Astrophysics
Tabular foundation models for the estimation of probabilistic quasar photometric redshifts in S-PLUS
Raquel R. Valença, Lilianne Nakazono, Rafael Izbicki et al. (+6 more)
We assess whether tabular foundation models can be used as off-the-shelf probabilistic photometric-
redshift estimators for
quasars in the 12-band S-PLUS DR6 survey, where colour-
redshift degeneracies produce multi-modal posteriors and spectroscopic training sets are shifted relative to the photometric population. TabPFN 2.5, RealTabPFN 2.5, and TabICL are benchmarked against eight task-specific baselines, including linear conditional Gaussians, FlexZBoost, mixture-density networks, normalising flows, random forests, and gradient-boosted trees, with training sets from 500 to 121,626
quasars, using both density and point-prediction metrics, together with importance-weighted scores that approximate deployment on the photometric target sample. TabPFN 2.5 is best or statistically tied for best on all metrics except the unweighted CDE loss, on which the normalising flow is statistically tied and attains the lowest mean value; its largest gains occur for small training sets and in difficult regimes (very bright and faint sources, high
redshift), while retaining near-nominal calibration under
covariate shift. Its main practical cost is inference: with frozen weights, large support and target catalogues require substantial GPU/accelerator
memory, and full-catalogue deployment may need support-set subsampling or
distillation. SHAP attributions identify WISE W1/W2 as the strongest individual predictors, with UV and optical bands offering non-negligible refinements. We conclude that TabPFN 2.5 is a strong default for probabilistic
quasar photo-z estimation, particularly when training data are limited or when calibration under
covariate shift is critical.
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All authors Raquel R. Valença, Lilianne Nakazono, Rafael Izbicki, Marco Henrique de Almeida Inácio, Bruno Marcondes e Resende, Maycon Jorge Deláqua da Silva, Kiana Coimbra Buin Lins, Natanael M. Cardoso, Claudia Mendes de Oliveira
Atmospheric and Oceanic Physics
Stochastic Emulation of a Fully Coupled Preindustrial E3SMv3 Simulation
Elynn Wu, James P. C. Duncan, Troy Arcomano et al. (+11 more)
We present a
stochastic coupled emulator of E3SM version 3, built on the SamudrACE framework, which couples an atmosphere emulator (ACE2) with a full-depth ocean emulator (Samudra). We replace the deterministic atmosphere emulator with its
stochastic counterpart, ACE2S, and fine-tune the coupled system with a probabilistic objective, so that the atmosphere acts as a source of internal variability for the ocean. Trained on 105 years of a pre-industrial control simulation and evaluated on an independent 400 years, the emulator reproduces E3SMv3's mean
climate state with biases much smaller than existing model-to-observation differences. Relative to a deterministic baseline,
stochastic training maintains internal variability across timescales, most notably in the ENSO power spectrum, eddy-rich SST anomalies, and sea ice variability in the marginal ice zone. The emulator captures daily precipitation accurately up to the 99.99th percentile, but underestimates the rarest tropical extremes. These results show that
stochastic coupled emulators can reproduce long-timescale variability with high fidelity, while extrapolation to unseen extremes remains a key challenge.
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All authors Elynn Wu, James P. C. Duncan, Troy Arcomano, Jeremy McGibbon, Oliver Watt-Meyer, Christopher S. Bretherton, Naser Mahfouz, Claudia Tebaldi, Luke Van Roekel, Andrew Roberts, Wuyin Lin, Finn Rebassoo, Jean-Christophe Golaz, Peter M. Caldwell
Soft Condensed Matter
Signatures of auxeticity in microgels at low and ultralow crosslinker concentration
Susana Marín-Aguilar, Leah Rank and Emanuela Zaccarelli
Auxetic behavior, characterized by a negative Poisson's ratio, is a counterintuitive mechanical response exhibited, among other systems, by certain
polymer networks. Here, through in silico simulations we investigate the mechanical response of thermoresponsive microgels across the volume phase transition upon varying crosslinker concentration down to ultralow conditions, a regime so far unexplored. After refining the method to estimate the elastic
moduli based on
equilibrium shape fluctuations for the challenging case of ULCs, which are very sparse networks with rather anisotropic shape, we are able to show the onset of auxetic behavior near the volume phase transition for microgels with crosslinker concentration of ~ 1%. In addition, we find that ULC microgels exhibit a slightly negative Poisson's ratio across the whole swollen regime. Further examining the auxetic response within the inner region of the network, we also demonstrate that, for ULC microgels, this extends at all length scales, suggesting that it is an intrinsic property of the weakly connected
polymer network. The present findings should likely stimulate novel experimental investigations, aiming to measure the Poisson's ratio of individual low and ultralow crosslinked microgels, to verify these intriguing numerical predictions.
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General Relativity and Quantum Cosmology
On the nature of oscillating modes of proto-neutron stars
Dimitra Tseneklidou, Alejandro Torres-Forne, Pablo Cerda-Duran et al. (+2 more)
Newborn proto-
neutron stars (PNS) are potential targets of gravitational wave asteroseismology, the study of the (inner) structure of
stars via their oscillation modes. To prepare for the eventual detection of such modes by current and future gravitational wave observatories, theoretical studies have obtained the possible spectrum of oscillations. However, there has been disagreement when it comes to identifying and classifying specific modes according to the physical mechanism that excites them. In this paper, we present a novel scheme to classify the oscillation modes of a newly born PNS surrounded by a stalled
accretion shock in core-collapse
supernovae (CCSNe). Our classification is physically motivated, as it is based on the energy of the restoring forces of the mode. We investigate the nature of the modes by considering the different regions of the CCSN that they stem from. We apply this scheme to a set of 28 non-rotating 1D, 2D and 3D CCSN simulations performed with two different numerical codes and using different progenitors and equations of state. In that way, we find that there are different families of f-, p- and g-modes in the system, living in different areas. More specifically, we identify two families of f- and p-modes associated with the PNS and the shock, respectively, and two families of g-modes originating from the two convectively stable regions, one in the PNS core and one near its surface. We also find that the dominant high-frequency emission mode is the f-mode of the PNS, associated with the strong density gradient at its surface. Our classification procedure is automatic, performs consistently for all the models considered, and paves the way to systematic studies of the dependence of the mode frequencies on the PNS properties, with direct application to parameter estimation from future observations of gravitational wave signals.
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All authors Dimitra Tseneklidou, Alejandro Torres-Forne, Pablo Cerda-Duran, Martin Obergaulinger, Jose Antonio Font
Materials Science
Helimagnetism from competing intra- and interchain interactions in CrBr$_2$ and CrI$_2$
John A. Schneeloch, Matthew B. Stone, Zachary Morgan et al. (+1 more)
CrBr$_2$ and CrI$_2$ are promising platforms for studying the effect of dimensionality on
magnetic order, having been isolated in a 3-, 2-, and 1-dimensional form as bulk
crystals, monolayers, and individual chains encapsulated in carbon nanotubes. However, the interactions that give rise to their helimagnetic order are unknown. Via inelastic
neutron scattering on single
crystals, we have determined the exchange interactions of these compounds from the
spin wave dispersions, finding that the helimagnetic order arises primarily from competing
antiferromagnetic interactions between intrachain and interchain nearest-neighbors. Single-ion anisotropy is substantial, modulating the helical
spin rotation and gapping the inelastic intensity at points of branch crossings. As temperature increases, long-range order vanishes but intralayer correlations remain detectable up to at least 50 K.
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All authors John A. Schneeloch, Matthew B. Stone, Zachary Morgan, Despina Louca
High Energy Astrophysical Phenomena
Astrophysical Constraints on Hadron–Quark Crossover in Hybrid Neutron Stars
Gábor László Kasza and György Wolf
We investigate astrophysical constraints on hybrid
neutron-
star equations of state constructed by combining an extended linear sigma model description of
quark matter with several representative hadronic equations of state through a smooth
hadron–
quark crossover. Four different hadronic models are examined in order to explore the model dependence of the resulting hybrid equations of state. After imposing stability, causality, perturbative QCD matching,
tidal deformability, and maximum-mass constraints, only the eLSM+GMSR(BSK16) construction remains fully consistent with current astrophysical observations. The surviving parameterizations are further constrained using
Bayesian inference based on NICER mass–radius measurements and the GW170817 gravitational-wave event. The posterior distributions favor a broad
hadron–
quark crossover occurring at relatively high
baryon densities, while the formation of extended pure
quark cores is strongly disfavored. Instead, the current observations favor
neutron stars containing an extended mixed
hadron–
quark transition region. We also investigate the implications of the inferred maximum-mass distribution for the secondary object of GW190814 and find that, within the present model and adopted observational constraints, its interpretation as a
neutron star is unlikely.
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Solar and Stellar Astrophysics
Astro+ database. I. Description and first results
K. Rübke, A. Marco, I. Negueruela et al. (+4 more)
The vast amounts of spectroscopic data for massive
stars provided by previous and existing instruments on ground-based and space-based
telescopes have saturated our capability to process them by human inspection routines. Consequently, there is a pressing need for fully automatic machine-assisted tools to help handle incoming data. To this end, we present the development of a massive
star spectroscopic interactive database, Astro+. We aim to provide users with a reliable, versatile, and user-friendly platform that will be significant for understanding massive
stars and set an important precedent for future open-access astrophysical research. This tool allows authorized users to upload their own spectra and, by using the fully automated tool HiLineThere, a Python-based program, it can homogeneously derive basic
stellar parameters, such as v_rad, v sin i, Teff and log g for massive OB-type
stars, using a
solar-
metallicity grid of FASTWIND models, and v_rad, [Fe/H], Teff and log g for red supergiant
stars, in a completely autonomous way. Here we present the first results of the tool HiLineThere on optical spectra for OB-type
stars and red supergiants. We compare the output of our analysis for OB-type
stars with literature values for a large sample of well-studied objects, finding differences within the expected error ranges: Teff ~ 800 K, log g ~ 0.1 dex, and v sin i ~ 10 km/s. Preliminary tests on early-B
stars also show consistent results during the transition to lower temperatures. For red supergiants, we find differences within 7 km/s in v_rad and ~300 K in Teff for two test samples.
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All authors K. Rübke, A. Marco, I. Negueruela, A. Herrero, S. Simón-Díaz, H. M. Tabernero, L. R. Patrick
Solar and Stellar Astrophysics
The Carbon Giant Population Revealed by Gaia DR3
Benjamin R. Roulston and Paul J. Green
Classical carbon
stars (atmospheric C/O >1) are asymptotic
giant branch (AGB)
stars that become carbon-rich through third dredge-up during the thermally pulsing AGB phase. However, carbon
stars also occur among red
giants and main-sequence
stars, where the carbon is thought to originate from binary mass transfer from a former AGB companion. Using the all-sky catalog of G<16.5 mag
Gaia DR3 carbon
stars from Roulston et al. (2025), we investigate a uniform, high-confidence sample of carbon
giants in the Milky Way, its globular clusters, and nearby Local Group
galaxies. We identify 6937 carbon
giants in the Large Magellanic Cloud, 2148 in the Small Magellanic Cloud, and 219 associated with the Sagittarius
dwarf spheroidal, nearly quadrupling the previously known sample in the latter. We identify several candidate carbon symbiotic
stars through their X-ray counterparts. The mean absolute C-AGB magnitude, $M^0_J=-6.30$ in the LMC and -6.15 in the SMC, agrees closely with the photometrically derived values of Ripoche et al. (2020), reinforcing the utility of carbon AGB
stars as distance indicators. From 4276
Galactic carbon
giants with $M_G<0$ and $|b|>5^\circ$, we measure a local disk space density of $n_0=11\pm0.5\times10^{-8},\mathrm{pc}^{-3}$ and a scale height of $H_z=257\pm4$ pc. Lower-luminosity carbon
giants exhibit significantly larger
Gaia DR3 RUWE values than C-AGB
stars, providing strong evidence that most are extrinsic post-mass-transfer systems, likely evolved
dwarf carbon
stars. C-AGB
stars are more tightly confined to the
Galactic disk and are rare inside $R\lesssim7$ kpc, consistent with
Galactic age and
metallicity gradients, whereas the lower-luminosity carbon
giants have a larger scale height and require an additional
halo component.
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Materials Science
Balanced electron and phonon heat transport in metallic $\varepsilon$-TaN
Sungyeb Jung, Hongze Li, Yudan Li et al. (+6 more)
Most materials with high thermal conductivity belong to one of two classes: metals, where heat is carried predominantly by electrons, and
insulators, where heat transport is dominated by the
phonon contribution. Materials that combine substantial electronic thermal conductivity and
lattice thermal conductivity are rare, because the mechanisms that favor electron transport typically suppress
phonon transport, and vice versa. Here, we report the theoretical prediction and experimental realization of such a material, metallic $\varepsilon$-TaN. Our calculations predict a total thermal conductivity at room-temperature of 273$\pm$5Wm$^{-1}$K$^{-1}$ in single
crystals and 145$\pm$5Wm$^{-1}$K$^{-1}$ in polycrystals with 0.5$\mu$m grains, with an unusually large
lattice contribution (79%) for a metal. The latter value is in agreement with our local transient thermoreflectance measurements on polycrystalline samples yielding $\sim$130Wm$^{-1}$K$^{-1}$. We show that the balanced electronic and
lattice thermal conductivities of $\varepsilon$-TaN originate from a combination of large
Fermi velocity and small
Fermi density of states on the electron side, and large speed of sound and wide
phonon gap on the
lattice side.
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All authors Sungyeb Jung, Hongze Li, Yudan Li, Noah Rossignol, Woongchul Choi, Yaguo Wang, Jianshi Zhou, Li Shi, Feliciano Giustino
General Relativity and Quantum Cosmology
Late-Time Cosmic Acceleration in Hořava-Lifshitz Gravity: Observational Evidence from Cosmic Chronometers and Pantheon+SHOES Datasets
Shivani Sharma and R.Chaubey
We investigate the cosmological implications of Horava-Lifshitz (HL)
gravity using a
redshift-dependent deceleration parameter of the form $q(z) = q_0 + \frac{q_1 \ln(1+z)}{1 + n\ln(1+z)}$, from which the Hubble parameter $H(z)$ is derived analytically. This parametrization captures the transition from early deceleration to late-time acceleration, with a logarithmic correction governed by $n$ that distinguishes it from standard kinematic models. Model parameters $H_0$, $q_0$, $q_1$, and $n$ are constrained via MCMC using
cosmic chronometer (CC) and Pantheon+SHOES
datasets, individually and in combination. Across all
dataset combinations, $q_0 < 0$, confirming ongoing accelerated expansion. The reconstructed $H(z)$ is consistent with $\Lambda$CDM at low
redshifts, with mild deviations at higher
redshifts. The $\{r, s\}$ statefinder parameters indicate that the model evolves smoothly, beginning with Chaplygin gas-type behaviour, crossing the $\Lambda$CDM fixed point, and settling into a quintessence-like phase at late times. The $Om(z)$ diagnostic reveals negative slopes throughout, indicating quintessence-like dark energy ($w > -1$). Present-day
cosmic age estimates from the individual and combined
datasets yield $t_0 \approx 13.7$ Gyr, in agreement with Planck 2018 constraints.
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High Energy Physics (Phenomenology)
Extraction of baryon number susceptibilities at finite density from heavy-ion collisions
Grégoire Pihan, Roman Poberezhniuk, Volodymyr A. Kuznietsov et al. (+1 more)
We present, to our knowledge, the first
Bayesian extraction of
baryon number susceptibilities of QCD matter at finite
baryon density from heavy-ion collision data on
proton number cumulants. The framework embeds arbitrary equation-of-state susceptibilities $\chi_n^B$ into realistic hydrodynamic particlization hypersurfaces through maximum-
entropy freeze-out, maps the resulting (anti)
baryon fluctuations onto
protons, applies the experimental kinematic acceptance, and accounts for exact
baryon number conservation. Applying the framework to measurements of (net-)
proton number fluctuations in 0–5% central Au-Au collisions from the RHIC Beam Energy Scan in the
collider mode, we extract, at each collision energy, the second-order susceptibility normalized by the
hadron resonance gas value, $\chi_{2}^B/\bar{\chi}_{2}^B$, and the higher-order susceptibility ratios $\chi_{3}^B/\chi_{1}^B$ and $\chi_{4}^B/\chi_{2}^B$. We obtain tight constraints on $\chi_{2}^B$, with extracted values in quantitative agreement with
lattice QCD based estimates along the chemical freeze-out line for $\mu_B \lesssim 300$~MeV. At larger $\mu_B$, the extracted values indicate an enhancement of
baryon number fluctuations relative to the noncritical
lattice-based extrapolation and HRG baseline considered here. The third- and fourth-order susceptibilities are only weakly constrained. In particular, we find that the observed nonmonotonic collision-energy dependence of the
proton factorial cumulant ratio $\hat{C}_{3}/\hat{C}_{1}$ can be described without irreducible three- or four-
baryon correlations. This behavior emerges from the interplay between the energy dependence of $\chi_{2}^B$ and exact
baryon number conservation.
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All authors Grégoire Pihan, Roman Poberezhniuk, Volodymyr A. Kuznietsov, Volodymyr Vovchenko
Applied Physics · Cross-listed from cs.ET
Unsupervised Detection of Groundwater Storage Anomalies in Ghana Using GRACE Satellite Data
George Yamoah Afrifa, Theophilus Ansah-Narh and Marcellin Atemkeng
Groundwater variability in Ghana remains poorly characterized due to limited long-term in-situ observations. This study investigates groundwater storage anomalies using GRACE-derived data from 2004-2024 combined with statistical analysis and unsupervised machine learning. Groundwater anomalies were standardized using Z-scores, while an ensemble-based Isolation Forest framework was applied for anomaly detection. The results revealed substantial temporal variability, with persistent groundwater deficits during 2004-2009 followed by increasing positive anomalies after 2018. A total of 12 anomalous months were identified, comprising 5 deficit and 7 surplus events, with the strongest anomalies associated with groundwater deficits. Spatial analysis showed more frequent deficit anomalies in northern Ghana and stronger surplus occurrence in southern regions. Comparison with statistical thresholds further indicated that the machine learning framework captured additional subtle deviations beyond conventional threshold-based methods. Overall, the integration of GRACE observations with unsupervised anomaly detection provides a practical framework for groundwater monitoring in data-scarce environments.
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Strongly Correlated Electrons
Some features of high-temperature superconductivity on flat bands
V.R. Shaginyan, A.Z. Msezane and S.A. Artamonov
In this letter, we examine how the presence of flat band leads to the formation of a high-temperature
superconductor even in the case of repulsive pairing interactions. We also show that in the case of flat bands, the high-temperature superconducting state deforms the flat band, tilting it and making the effective mass finite. As a result, neither the superfluid weight nor the supercurrent disappear. Our results are in good agreement with experimental data.
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Quantum Physics
Bayesian approach to simultaneous quantum multiparameter estimation with finite data
Chun Kit Dennis Law and József Zsolt Bernád
Multiparameter estimation remains a fundamental challenge in
quantum estimation theory because the optimal measurements associated with different parameters are generally incompatible. In this work, we develop a
Bayesian framework for the simultaneous estimation of multiple parameters. Our approach builds on Personick's method, in which the estimation problem is reduced to a set of Lyapunov equations whose solutions define optimal observables for the individual parameters. Since these observables generally do not commute, we construct a convex combination of the solutions, parameterized by a set of variational parameters. The spectral decomposition of the resulting operator defines a parametrized projection-valued measure. The resulting projective measurement determines the likelihood function, from which the minimum mean-square error
estimators and the corresponding
Bayesian mean-square errors are obtained, following standard
Bayesian procedures, as functions of the variational parameters. To determine their optimal values, we formulate a minimax optimization problem based on the normalized
Bayesian mean-square errors, introducing a min-max normalization procedure that enables a meaningful comparison of estimation errors associated with different parameters. This optimization yields a variationally optimized projective measurement for simultaneous
Bayesian estimation. Two
qubit examples, involving phase estimation and the estimation of parameters defining convex combinations of
unitary operations, demonstrate the construction of optimized projective measurements and the corresponding minimum mean-square error
estimators within the proposed framework for finite data sets.
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