Atmospheric and Oceanic Physics
Sampling sea state using a diffusion model
Jiarong Wu, Bertrand Chapron and Laure Zanna
Sea state prediction is essential for operational maritime applications and coupled earth system modeling, yet current spectral wave models remain computationally prohibitive for many use cases, including online coupling to
climate simulations and making probabilistic (ensemble-based) predictions. While deep learning has recently demonstrated strong performance in weather
forecasting, existing AI-based wave models are predominantly deterministic and largely limited to bulk variables such as significant wave height, leaving probabilistic sea state estimation largely unexplored. In this work, we propose a
diffusion-based generative model for global sea state estimation that conditions on a relatively long history (5 days) of global wind forcing. This generative model directly samples the complex conditional distribution of sea state without autoregressive time-stepping. Unlike prior approaches, our framework naturally extends beyond bulk variables to estimate partition-related variables and derived quantities, such as Stokes drift and mean square slope. Trained on a 30-year global WAVEWATCH-III hindcast, the model achieves substantial computational acceleration compared with numerical spectral models while delivering skillful predictions and a calibrated ensemble spread for the bulk variables. Our results suggest that
diffusion-based sea state sampling offers a promising path toward probabilistic wave
forecasting and efficient coupling of sea state information into broader earth system models.
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Mathematical Physics
A new formulation of metriplectic dynamics with an application to quasigeostrophic ocean modeling with advected quantities
Francisco J. Beron-Vera and Erwin Luesink
A general formulation of metriplectic dynamics is presented, where the metriplectic four-bracket is constructed by multiplying two skew-symmetric brackets. The new formulation is then used to introduce irreversibility in a generalized two-dimensional (2D) quasigeostrophic (QG) upper-ocean model involving advected quantities, with the thermal QG model as a special case. By construction, the resulting dynamics ensure the conservation of internal energy and the generation of
entropy, in accordance with the first and second laws of thermodynamics. Our metriplectic dynamics formulation allows for a flexible specification of irreversibility, ranging from a type that results in nearly material conservation of potential vorticity to the representation of realistic forcing and dissipation in 2D QG ocean modeling with advected quantities.
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Earth and Planetary Astrophysics
Two inner dust clumps in PDS 70. A third protoplanet traced by trojan material or a substructured inner disk?
O. Balsalobre-Ruza, V. Christiaens, N. Huélamo et al. (+18 more)
The PDS 70 cavity hosts two confirmed directly imaged protoplanets and a third inner
planet candidate at 13au, labeled PDS 70 d. Despite its Keplerian motion, its unusually blue spectrum challenges a planetary interpretation. We further investigate the presence and nature of a third inner
planet using new SPHERE and
GRAVITY+ observations. Using the
star-hopping strategy, we obtained coronagraphic IRDIS polarimetric observations in the H-band, and non-coronagraphic observations with IRDIFS in the YJHK-bands. We also searched for a planetary signal with
GRAVITY in the 4UT configuration. We consistently detect two elongated inner emissions with SPHERE: the previously proposed
planet candidate and another feature that appears to share the same orbit while leading it by ~120$^\circ$. Both features show
dust-scattered-light spectra but different colors, possibly indicating different grain sizes. Such configuration is consistent with co-orbital
dust accumulated at the stable Lagrangian regions of a distinct and yet undetected
planet.
GRAVITY yields a marginal (3$\sigma$) detection at the predicted location along the same orbit ($\rho=76.2\pm0.29$mas, PA=$226.50\pm0.21^\circ$), and consistent with a ~3$M_{\rm Jup}$
planet. This
planet-like signal is aligned with a narrow shadow that we detect in the outer disk. We also detect polarized emission very close to the
star likely arising from the inner disk. The apparent
embedding of the two
dust clumps within it motivates an inner-disk origin as an alternative scenario. We conclude that the previously reported third
planet candidate traces a
dust clump either trailing an unseen
planet on the same orbit or a rotating substructure within the inner disk. Further observations are needed to test these scenarios. Confirming the new
GRAVITY planet-like signal would support co-orbital substructures as indirect tracers of protoplanets.
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All authors O. Balsalobre-Ruza, V. Christiaens, N. Huélamo, I. Hammond, M. Benisty, S. Lacour, D. Blakely, R.G. van Holstein, J. Latour, J. Lillo-Box, Z. Wahhaj, D. Trevascus, O. Absil, J. Bae, C. Charalambous, I. de Gregorio-Monsalvo, A. Leleu, I. Mendigutía, C. Petrovich, Á. Ribas, S. Juillard
Physics and Society
Low-dimensional Dynamics of the Social Compass Model
Corbit R. Sampson and Juan G. Restrepo
The social compass model has been recently proposed as a model for depolarization in populations where individuals have multiple, possibly correlated, opinions. Previous work has focused on the steady state of this model, but has not addressed the dynamics leading to depolarization. We show that the macroscopic dynamics of the social compass model can be described using the Ott-Antonsen Ansatz and that, for initially clustered opinions, the resulting equations reduce to a finite-dimensional system of ordinary differential equations. We study the linear stability of the polarized state and find a dispersion relation for the growth rate of perturbations from this state. We find that the critical coupling for depolarization depends only on the first inverse moment of the conviction distribution, whereas the rate of depolarization depends on higher moments. Consequently, conviction distributions with the same critical coupling can exhibit vastly different depolarization timescales. We also demonstrate how our analysis can be extended to study depolarization in the presence of community structure.
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Fluid Dynamics
Geometry-Driven Passive Fluid Transport in Paper-Based Microdevices
Mohd Shafiq Nasir, Akimitsu Kugimiya and Muhammad Salman Al Farisi
Channel geometry strongly influences capillary-driven fluid transport in paper-based devices, yet systematic comparative studies correlating
geometric design with flow behaviour and analyte confinement remain limited. The present study investigates five distinct channel geometries namely converging-diverging, diverging-converging, wide-to-narrow, circular, and rectangular that was fabricated on cellulose filter paper with a standardized area of 32.5 mm\textsuperscript{2} and analyzed using geometry-adapted extensions of the Lucas–Washburn equation. Pyrene and benz[{\alpha}]anthracene were employed as fluorescent model analytes to enable UV-based quantification of analyte confinement within each geometry. Flow transport times ranged from 23.1 s (circular, fastest) to 65.0 s (diverging-converging, slowest), with corresponding mean velocities of 0.571 and 0.284 mm/s for pyrene respectively, demonstrating that channel geometry strongly influences capillary transport in paper-based devices. Diverging-converging and wide-to-narrow designs produced the greatest analyte confinement by imposing flow retardation and sustained channel acceleration respectively, while circular and rectangular designs yielded relatively uniform velocity distributions and weaker confinement. Cyclodextrin-functionalized chitosan coatings served as a surface chemistry tool to anchor analyte retention at designated preconcentration zones, enabling
geometric effects to be isolated and quantified. Computational fluid dynamics simulations, calibrated against experimental flow data and validated through a mesh independence study, reproduced the experimentally observed velocity magnitude distributions across all five geometries, showing semi-quantitative agreement with geometry-adapted Lucas–Washburn predictions.
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General Relativity and Quantum Cosmology
Effect of the magnetic monopole charge on Dirac entanglement and Bell non-locality in Hayward spacetime
Abdessamie Chhieb and Mohamed Ouchrif
We investigate bipartite
quantum correlations of Dirac fields in the spacetime of a Hayward regular black hole. Using the Wootters concurrence and the CHSH Bell parameter, we analyze the influence of Hawking radiation on an entangled state shared by an inertial observer and a near-horizon observer. We show that, unlike the bosonic case, fermionic correlations remain nonzero even in the infinite-temperature limit owing to the Pauli exclusion principle, while part of the
entanglement is redistributed to inaccessible modes inside the horizon. The accessible modes exhibit Bell nonlocality for all finite Hawking temperatures, whereas the interior modes never violate Bell's inequality. The Hayward regularity parameter $g$ affects the correlations only through the Hawking temperature, whose decrease with increasing $g$ enhances the preservation of
quantum information. These results suggest a close connection between singularity resolution and the robustness of fermionic
quantum correlations in regular black-hole spacetimes.
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General Relativity and Quantum Cosmology
Thermodynamics of thin-shell wormholes
Francisco S. N. Lobo and Manuel E. Rodrigues
We develop a unified thermodynamic description of dynamic thin-shell wormholes, starting from the transparent (
vacuum bulk) case and then relaxing the transparency condition to include bulk matter crossing the throat. For isolated shells, we show that the
entropy is conserved under transparent
evolution, $TdS=0$, which holds for arbitrary dynamical motion of the throat within the assumptions of the thin-shell formalism. When bulk matter is present, the generalised first law becomes $T\dot{S}=A\Phi$, where $\Phi$ is the net energy flux;
entropy increases (decreases) when matter flows into (out of) the shell. Explicit expressions for the flux are provided for null
dust and massless scalar fields, and
quantum pair production (Hawking-like emission) is also discussed. A formulation of the generalised second law is presented, and it is consistent with standard thermodynamic expectations under conditions where heat flows from hotter to colder regions. As a concrete astrophysical application, we study
accretion of null
dust: the critical
accretion rate above which the throat becomes dynamically unstable depends sensitively on the spacetime geometry and the shell equation of state, highlighting the environmental dependence of these configurations. Fluctuations in the energy flux induce a
stochastic force on the throat dynamics, leading to a Langevin description with an associated fluctuation-dissipation relation. This results in
diffusion of the throat radius and additional
entropy production. The framework applies to a broad class of spherically symmetric thin-shell constructions within general relativity. Our results provide evidence that thin-shell wormholes admit a consistent thermodynamic description, quantify their sensitivity to
accretion processes, and suggest possible avenues for probing exotic compact objects with future gravitational wave observations.
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Earth and Planetary Astrophysics
The Astrodynamics Primer on Cislunar and Translunar Space
Aaron J. Rosengren, Anjali Rawat, Bhanu Kumar et al. (+1 more)
The Earth-Moon environment is multiscale and strongly nonuniform, yet it is often discussed as a single cislunar regime. In reality, circumterrestrial space is partitioned by changes in perturbation hierarchy, by gateway
topology, and secular and resonant structures that differ qualitatively across the domain. This paper develops a unified spatiographic description of that structure, combining perturbative theory, semi-analytical resonance cartography, restricted multi-body dynamics, and direct numerical mapping. The terrestrial-cislunar transition is sharpened through the Laplace radius, beyond which lunisolar torques overtake the classical oblateness-dominated picture. Earthward of the Moon, cislunar space divides into a secularly dominated inner zone and an outer zone structured by interior lunar mean-motion resonances. Near the Moon, circumlunar space forms a distinct dynamical enclave organized by the EM gateway geometry and the lunar SOI. Beyond the Moon, translunar space forms an outer circumterrestrial province in which the Moon acts as an interior perturber, the Sun remains an exterior perturber, and the resulting dynamics acquire a mixed lunisolar secular and resonant architecture before weakening outward toward heliocentric behavior. These results are synthesized through MEGNO and fate-class cartographies across six numerical map domains. The maps reveal where quasiperiodic confinement survives, where resonance overlap and gateway transport produce sticky residence and organized escape, and where
solar forcing becomes a qualitative architectural ingredient. Placed alongside a curated catalog of satellites and debris, the framework provides a dynamical geography of this environments that clarifies the transitions among cislunar, circumlunar, and translunar motion and offers a more precise basis for interpreting stability, transport, and long-term Earth-bound behavior.
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All authors Aaron J. Rosengren, Anjali Rawat, Bhanu Kumar, Shane D. Ross
Instrumentation and Methods for Astrophysics
Extending the SKA Across Africa: The Case for a Continental African VLBI Network
Emmanuel K. Bempong-Manful, Jompoj Wongphechauxsorn, Jack Radcliffe et al. (+31 more)
The African continent holds the key to unlocking the full potential of global Very Long Baseline Interferometry (VLBI). Strategic placement of
radio telescopes across Africa provides the crucial north-south and intermediate baselines that are currently missing from the global VLBI network. This expansion will dramatically enhance imaging fidelity and resolution. In this chapter, we propose a
vision for a continental African VLBI Network (AVN) that will operate in close synergy with SKA-Mid, enabling transformational science across all
cosmic scales. While only the Hartebeesthoek
Radio Astronomy Observatory (HartRAO) in South Africa and the Ghana
Radio Astronomy Observatory (GRAO) are currently operational, several partner countries are in the process of refurbishing or converting existing
antennas. Here, we advocate for the expansion of this network through the deployment of a limited number of SKA-Mid-type
telescopes across the continent, creating an "African arm" of SKA-VLBI. With a maximum baseline of ~ 9000 km (from Rabat, Morocco to Cassis, Mauritius), the proposed continental facility will surpass for example, the resolution that will be achieved by the next generation Very Large Array (ngVLA) by ~ 10 % at similar observing frequencies and significantly enhance global VLBI coverage. Beyond the scientific and technical gains, the AVN represents a unique opportunity for sustainable growth in human capital, education, and innovation across Africa. Developing and operating a continental VLBI array will train the next generation of engineers, data scientists, and astronomers, stimulate local industry, and inspire public engagement in science and technology. We outline the current status, challenges, and potential roadmap towards realizing this
vision, and we highlight how a continental African VLBI network will position Africa at the forefront of global
radio astronomy.
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All authors Emmanuel K. Bempong-Manful, Jompoj Wongphechauxsorn, Jack Radcliffe, Melvin Hoare, Olga Bayandina, Pfesesani V. van Zyl, Cristina García-Miró, Candela Chico, Naomi Asabre Frimpong, Hans-Rainer Klöckner, Valente Cuambe, Carla S. Mitchell, Saul P. Phiri, Benedicta Woode, Emmanuel Proven-Adzri, Willice Obonyo, Tyler L. Bourke, Cristiana Spingola, Matthias Kadler, Ailing Wang, Roger P. Deane, Isabella Prandoni, Rocco Lico, James O. Chibueze, Robert Beswick, Simon Garrington, Benito Marcote, Tao An, Marcello Giroletti, Isaac M. Mutie, Anne-Kathrin Baczko, Johannes Allotey, Stefano Giarratana, Rasha M. Samir
Plasma Physics
Integrating Gyrokinetic Flux Predictions with Ideal MHD Stability Boundaries
J. McClenaghan, K. E. Thome, T. F. Neiser et al. (+5 more)
Accurate prediction of pedestal height and width in tokamaks remains a critical issue as it strongly influences the predicted
plasma performance of all future reactors. We present an integrated pedestal-stability workflow that combines
equilibrium scans with magnetohydrodynamic (MHD) stability analysis using ELITE and GATO and gyrokinetic transport predictions using CGYRO/QLGYRO. The workflow reproduces the characteristic KBM first- and second-stability structure previously identified in gyrokinetic pedestal studies. Applied to spherical tokamaks (STs), the workflow shows good agreement with past studies when low-n peeling stability is included, emphasizing the importance of resolving low-n physics in ST pedestals. Extending the analysis to SPARC-like, high toroidal field
plasmas, kinetic ballooning mode (KBM) and microtearing mode (MTM) heat fluxes are found to increase strongly with toroidal field, suggesting that access to the KBM second-stability region may become significantly more difficult in high toroidal field devices. Comparison with global ELITE finite-n analysis at SPARC parameters suggests that the H-mode pedestal lies in an intermediate regime bounded by local KBM second stability on one side and global finite-n ballooning instability on the other, consistent with the EPED picture once global effects are included
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All authors J. McClenaghan, K. E. Thome, T. F. Neiser, J. Candy, F. D. Halpern, T. H. Osborne, S. Saarelma, the MAST-U team
Atmospheric and Oceanic Physics · Cross-listed from cs.LG
Does Aurora Encode Atmospheric Structure? Latent Regime Analysis and Attribution
Emma Kasteleyn and Ana Lucic
ML foundation models are able to emulate atmospheric dynamics accurately and efficiently but operate as opaque “black boxes”. We investigate the internal representations of the Aurora model using spatially pooled PCA and layer-wise relevance propagation (LRP). We find evidence that Aurora's latent space is primarily organized by seasonal cycles, whereas extreme storm events do not form a linearly separable cluster. LRP indicates that the model attends to features consistent with the 3D vertical structure of the Great Storm of 1987. Perturbation tests show masking relevant regions degrades forecasts $3.31\times$ more than random masking. These findings suggest that Aurora learns meteorological coherence and vertical structure without explicit instruction.
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Earth and Planetary Astrophysics
Predictions of Transiting Exoplanet Confirmations from Rubin LSST Surveys
Suber Corley, Eric Feigelson, Claudio Caceres et al. (+2 more)
We assess the prospects for
exoplanet transit observations in the 10-year Wide Fast Deep (WFD) and Deep Drilling Field (DDF) surveys within the Legacy Survey of Space and Time (LSST) mission of the Vera C. Rubin Observatory. We construct a framework for systematic assessment of expected
exoplanet yields, highlighting the principal limitations imposed by the survey observing strategy and cadence. We simulate light curves with a wide range of exoplanetary system models derived from
planet occurrence rates developed with data from the Kepler mission. Transit counts for the
stellar population are calculated using the TRILEGAL
Galactic structure model, incorporating
telescope sensitivity and survey cadences. We apply the constraints that the full duration of at least three transits must be observed and that the signal-to-noise ratio will support detectability. The observations were then validated using the Transit Least Squares periodogram. Our findings indicate a limited potential for
exoplanet confirmations under the current survey design. Only a small number of hot
planets orbiting faint M class main sequence
stars will be confirmed in the DDF fields. The WFD survey is projected to produce no confirmations. These findings underscore the constraints imposed by the sparse, multi-band observing strategy, which prioritizes cosmology and extragalactic science over the continuous photometric coverage required for confirmations.
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All authors Suber Corley, Eric Feigelson, Claudio Caceres, Bolivia Cuevas-Otahola, Andjelka Kovacevic
High Energy Physics (Theory)
Deformed BTZ Radiance and Single Trace $T\bar{T}$ Holography
Daniel Vainshtein
We generalize the "holar wind" mechanism proposed in arXiv:2303.00234 to the case of rotating $\lambda$-deformed BTZ black holes. These backgrounds, which interpolate between $AdS_3$ in the infrared and a linear dilaton spacetime in the ultraviolet, are realized as an exact $\frac{SL(2,\mathbb{R})_k\times U(1)}{U(1)}$ gauged-WZW worldsheet theory. The long string sector of the theory provides a
holographic dual to single-trace $T\overline{T}$ deformed symmetric product $\mathcal{M}^p/S_p$ $CFT_2$ with a seed $\mathcal{M}$ carrying a central charge $c=6k$. By analyzing the geodesics and tunneling rates of probe particles and winding long strings, we show that the emission probabilities for both positive and negative deformation couplings are universally governed by the change in the Bekenstein-Hawking
entropy, $\Delta S_{BH}$. A central result of our analysis is that the consistency of long string emission within the grand canonical ensemble dictates a unique value for the background B-field at the origin. We demonstrate that this thermodynamically fixed value matches precisely the prediction required for the string excitation spectrum to agree with the $\mathbb{Z}_w$ twisted sector of a single-trace $T\overline{T}$ deformed symmetric product orbifold. Finally, we sketch the extension of these results to a broader class of black holes whose long string sector is dual to single-trace $T\overline{T} + J\overline{T} + T\overline{J}$ deformed theories.
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Astrophysics of Galaxies
Probing the Nature of Lyman Continuum Emitting and Low-metallicity Galaxies Using the SKA
Omkar Bait, Daniel Schaerer and Mark Sargent
The sources responsible for
cosmic reionization remain a key open question in observational cosmology. Recent JWST results increasingly suggest that low-mass
star-forming
galaxies (e.g., compact starbursts and strong emission-line systems) dominated the ionizing
photon budget. The physical mechanisms driving Lyman continuum (LyC)
photon escape, including
supernova, radiative, and
cosmic-ray feedback, and the origin of extreme ionization conditions, remain poorly understood.
Radio continuum (RC) emission, a well-established
star-formation tracer in normal
galaxies, is not yet well characterized in such extreme systems, which exhibit high
star-formation rate densities, young
stellar populations, low
metallicity, and hard ionizing spectra. Targeted mid-frequency ($1-15$,GHz) observations with SKA precursors have begun probing low-
redshift LyC emitters (LCEs), revealing links between RC spectral index, LyC escape fraction, ionization conditions,
metallicity, and SFR surface density, alongwith deviations from the canonical RC$-$SFR relation. The higher sensitivity of the SKA Array Assemblies across Bands $\sim 1-5$ will enable systematic studies of fainter LCEs and low-mass, metal-poor
galaxies. We present number density predictions for LCE candidates at $z \sim 1$-$3$, showing that SKA-Mid surveys can assemble samples of $\sim10-100$ candidates per square degree over a
star-formation rate range of $1-100$,$M_{\odot}$yr$^{-1}$, making a dedicated SKA Large Programme scientifically feasible. With the full SKA, in synergy with JWST and next generation
telescopes, multi-wavelength analyses will robustly constrain the thermal and non-thermal RC components and
cosmic-ray energy spectra, providing critical insights into the feedback processes governing LyC escape and
star formation in the early universe.
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Quantum Physics
Equivalence of non-local computation tasks beyond Clifford operations
Andreas Bluhm, Simon Höfer, Alex May et al. (+2 more)
Non-local
quantum computation (NLQC) studies how two collaborating players can implement channels on distributed systems using a single simultaneous round of
quantum communication and shared
entanglement. NLQC has applications in diverse areas, ranging from
quantum position-verification to
quantum gravity. Recently, it has been realized that the relationships among families of NLQC tasks are highly structured: many seemingly distinct tasks are related by reductions, wherein implementations of one task can be used to efficiently implement a second task. This is analogous to the notion of reduction in complexity theory, and reveals the relative hardness of NLQC tasks. In this work we continue the study of reductions among NLQC tasks. We focus on NLQC examples of the greatest interest in
quantum position-verification; in particular examples involving large classical inputs and fixed-size
quantum inputs, since these constitute the most feasible protocols for position-verification schemes. Within this setting, we find many new relationships among NLQC tasks. For instance, protocols for the simplest example of redirecting a
quantum system based on a classical control imply protocols for controlled single
qubit measurements in arbitrary bases, the controlled application of any Clifford
unitary, and even the controlled application of any
unitary of the form $U=C_1DC_0$ with $D$ an arbitrary diagonal
unitary and $C_0, C_1$ Clifford
circuits. This implies that many feasible position-verification schemes have the same asymptotic scaling for their
entanglement cost, and hence a similar level of security. Our techniques rely on ideas from gate teleportation and measurement based
quantum computation, among other areas, bringing several new strategies into NLQC which may be of independent interest.
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All authors Andreas Bluhm, Simon Höfer, Alex May, Florian Speelman, Philip Verduyn Lunel
Fluid Dynamics
Variational derivation of a moist thermal rotating shallow water model
Colin J. Cotter, Darryl D. Holm and Oliver D. Street
We introduce a new energy-conserving, moist shallow water model with thermal stratification and rotation. The model is derived from a variational principle, using a Lagrangian expressed in terms of enthalpy. In this model, the latent heat from phase transitions modifies the buoyancy dynamics, which in turn feeds back to alter the vertically integrated hydrodynamic motion. Finally, we generalise this moisture parameterisation to non-hydrostatic Green-Naghdi equations.
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Optics
Generalized vibration curves for apodization and super-resolution in far-field diffraction
Lowell T. Wood
The Cornu spiral, widely used to analyze Fresnel diffraction, is a familiar example of a vibration curve, also known as an amplitude-phase curve or phasor diagram. A related construction appears in discussions of Fraunhofer diffraction, where the aperture function is uniform, making the curve's shape depend solely on phase. When the aperture function varies with position, however, both amplitude and phase determine the geometry. Here, vibration curves are extended to continuous, monotonic, symmetric, nonuniform aperture functions that produce either apodization (broadening of the central maximum with suppression of side maxima) or super-resolution (narrowing of the central maximum with enhancement of side maxima). These generalized vibration curves provide an intuitive visualization of how aperture structure shapes the far-field diffraction pattern. They clarify the mechanisms behind apodization and super-resolution and reveal how phasor rotation at the first diffraction zero provides a signature that characterizes the two effects. This unified perspective serves as a useful pedagogical tool for connecting
Fourier transforms, optical diffraction, and vibration curves in the undergraduate and graduate curriculum.
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Earth and Planetary Astrophysics
Architectures of Planetary Systems III: Excitation of Eccentricities and Inclinations
Alex R. Howe, Juliette C. Becker and Fred C. Adams
The current census of planetary systems displays a wide range of architectures. Extending earlier work, this paper investigates the correlation between our classification framework for these architectures and the distribution of eccentricities and inclinations of planetary orbits using both dispersion and normalized angular momentum deficit (NAMD) metrics. Orbital inclinations prove to be too strongly affected by observational biases to yield meaningful results, but the patterns in eccentricities reveal significant correlations. We find that systems with large gaps between
planets are more dynamically excited than closely-spaced systems, based on dispersion in eccentricity and an eccentricity-specific NAMD metric. Systems with detected outer
planets also appear dynamically excited, to a degree where our own
solar system appears to be dynamically colder than expected. We also predict the existence of a population of highly-inclined long-period
planets that is likely to be observed by upcoming astrometric surveys.
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General Relativity and Quantum Cosmology
Time-domain framework for the Teukolsky equation with a particle source using comoving hyperboloidal coordinates
Aditya Vaswani, Leor Barack, Oliver Long et al. (+1 more)
We present a scheme and implementation code for time-domain integration of the Teukolsky equation in 1+1 dimensions with a point-particle source, based on comoving, spatially compactified hyperboloidal coordinates. We demonstrate that the scheme evades the problem of nonphysical growing modes that plague some numerical
evolution schemes without compactification. Our use of comoving coordinates greatly simplifies the application of jump conditions on the particle's worldline. We develop our method and test its performance for a scalar field on a Schwarzschild background, first for a circular geodesic orbit source and then for a scattering geodesic orbit. We then present a test implementation of the method for the $s = -2$ Teukolsky equation, illustrating its long-term stability and absence of growing-mode behavior through comparison with similar results using noncompactified characteristic coordinates. Our method paves the way to calculations of the full gravitational self-force in extreme-mass-ratio scattering.
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All authors Aditya Vaswani, Leor Barack, Oliver Long, Rodrigo Panosso Macedo
Strongly Correlated Electrons
Odd-parity electronic order near the semiconductor limit
Jack Tregidga, Dibyata Rout, Johannes Hielscher et al. (+3 more)
Identifying materials platforms in which dilute carriers experience strong Coulomb interactions is a central challenge in the search for interaction-driven
quantum phases. In such systems, weak carrier screening can promote a variety of collective instabilities beyond the conventional
Fermi liquid paradigm, including superconductivity, Wigner crystallization, and odd-parity electronic order. Experimental realizations of such dilute, strongly interacting electronic systems remain rare in crystalline materials. Here we report a spontaneous odd-parity phase transition in the phosphide
semiconductor family $\textit{Ln}$Cd$_3$P$_3$ ($\textit{Ln}$ = La, Ce, Pr, Nd). Using optical second harmonic generation, we observe the onset of bulk inversion and rotational
symmetry breaking accompanied by the emergence of an in-plane polar axis. Second harmonic microscopy reveals three domain variants related by 120$^\circ$ rotations, while ultrafast transient reflectivity measurements uncover a pronounced electronic reconstruction across the transition. Remarkably, the ordered phase appears only in lightly self-hole-doped compounds and is absent in insulating SmCd$_3$P$_3$, indicating an essential role for itinerant carriers despite their extremely low concentration. Guided by density functional theory, we develop a four-band model of the valence states and show that modest interactions can stabilize odd-parity electronic order. The resulting phase combines a spontaneous
Fermi surface distortion with a momentum-dependent
bilayer polarization that breaks inversion
symmetry. Our results establish a route to interaction-driven parity breaking in dilute-carrier
semiconductors and identify honeycomb
bilayer systems as a promising platform for odd-parity electronic phases.
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All authors Jack Tregidga, Dibyata Rout, Johannes Hielscher, Josiah Turner, Stephen D. Wilson, John W. Harter
Lattice Field Theory
Isospin breaking corrections to a lattice QCD calculation of $\varepsilon'$
Norman H. Christ and Erik Lundstrum
Because of the $\Delta I = 1/2$ rule, the effects of electromagnetism and the isospin-breaking light
quark mass difference on the direct CP violation parameter $\varepsilon'$ may be as large as 25% and are consequently of immediate interest. In a
lattice QCD calculation the effects of isospin breaking on the various features of kaon decay can be clearly distinguished and those effects enhanced by the $\Delta I=1/2$ rule on $\varepsilon'$ explicitly identified. We show that all such enhanced effects can be captured in a QCD + QED
lattice calculation in which the exchanged
photon has an energy in an accessible, intermediate range between 0.5-2.0 GeV. Short-distance effects ($2.0 \mathrm{\ GeV} \lesssim E_\gamma$), usually treated in QCD and electroweak perturbation theory, are not enhanced by the $\Delta I=1/2$ rule, beyond the well-understood contribution of the two electroweak penguin operators. Infrared
photons do not contribute to $\varepsilon'$ while low-energy
photons ($E_\gamma \lesssim 0.5$ GeV) are not $\Delta I=1/2$ rule enhanced or are suppressed by one order in
chiral perturbation theory (ChPT). An explicit ChPT estimate of this low-energy-
photon contribution, a contribution that is difficult to determine in a finite-volume
lattice calculation, suggests that the effect on $\varepsilon'$ is on the order of 0.5%.
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High Energy Astrophysical Phenomena
Debiasing the Observed Fast Radio Burst Population with the CHIME/FRB Selection Function
Kyle McGregor, Jason W. T. Hessels, Victoria M. Kaspi et al. (+26 more)
The recent release of CHIME/FRB Catalog~2 provides the largest sample to date with which to investigate the intrinsic distributions of fast
radio bursts (FRBs). Leveraging an expanded campaign of 587,367 synethetic bursts injected into the live CHIME/FRB search pipeline, we perform a population analysis of the fluence, scattering timescale, pulse width, and dispersion measure distributions of Catalog~2 FRBs. We first infer the intrinsic population using a resampling-based framework that accounts for instrumental selection effects following previous CHIME/FRB population studies. A central goal of this work is to constrain the intrinsic distribution of scattering timescales, that remained weakly constrained in Catalog~1 owing to limited statistics at moderate and large scattering times ($\tau \gtrsim 10\,\mathrm{ms}$ at 600~MHz) and sparse injection coverage in this regime. Second, we construct an explicit multidimensional selection function by training a logistic regression model on the injected events. This model estimates the detection probability as a function of FRB observable properties, including higher-order interaction terms. We incorporate this selection function into a simulation-based inference framework to refine the inferred intrinsic scattering-timescale distribution. We find evidence for a slight downturn in the intrinsic FRB scattering timescale distribution, though a flat or slightly rising distribution cannot be ruled out, that is further supported through a comparison with the higher-frequency scattering timescale distribution observed by Commensal Real-time ASKAP Fast Transients (CRAFT) survey.
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All authors Kyle McGregor, Jason W. T. Hessels, Victoria M. Kaspi, Kaitlyn Shin, Fengqiu A. Dong, Naman Jain, Robert A. Main, Mawson W. Sammons, Michele Woodland, Daniel Amouyal, Derek Bingham, Charanjot Brar, Amanda M. Cook, Radu Craiu, Alice P. Curtin, Gwendolyn Eadie, Bryan M. Gaensler, Jeff Huang, Afrokk Khan, Calvin Leung, Kiyoshi W. Masui, Ayush Pandhi, Swarali Shivraj Patil, Aaron B. Pearlman, Sachin Pradeep E. T., Paul Scholz, Seth R. Siegel, Kendrick Smith, David C. Stenning
Earth and Planetary Astrophysics
DiskMINT-GARDEN: Self-consistent Models to Estimate Disk Masses
Dingshan Deng, Uma Gorti, Ilaria Pascucci et al. (+1 more)
We present DiskMINT-GARDEN, a grid of self-consistent models together with a fast, open source inference tool for disk masses. The grid is built on DiskMINT, a tool which couples hydrostatic disk structure, continuum/line radiative transfer, and a reduced CO chemical network including freeze-out, grain-surface conversion, and isotope-selective photodissociation. DiskMINT-GARDEN model grid spans a large range of
stellar mass ($0.1-2.0\,M_\odot$), gas disk mass ($10^{-5}-10^{-1}\,M_\star$),
dust-to-gas ratio ($0.003-0.1$), and characteristic radius ($10-300\,{\rm au}$), and provides synthetic ALMA observables. We train a machine-learning regression model to infer the disk mass,
dust-to-gas mass ratio, and disk size from the
dust continuum and $\mathrm{C^{18}O}$ line observations. Applying DiskMINT-GARDEN to archival ALMA data of 34 disks, we find gas masses in good agreement with dynamical and HD-based estimates. Comparing our results with estimates from chemical modeling using DALI, we find that their need for large-scale elemental or CO depletion can be accounted for by grain-surface chemistry implemented in DiskMINT, with CO conversion to CO$_2$ being one of the main reactions. Therefore, extant data suggest little chemical processing due to disk evolutionary processes.
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All authors Dingshan Deng, Uma Gorti, Ilaria Pascucci, Maxime Ruaud
Materials Science
Nanoscale Phase Distribution Governs Exchange Bias in Multiphase Magnetic Nanoparticles
Murtaza Bohra, Stefanos Giaremis, Vidyadhar Singh et al. (+3 more)
Exchange bias at ferromagnet-antiferromagnet interfaces underpins
magnetic memory, spintronic devices, and nanoscale electromagnetic technologies, yet its behaviour in complex nanoscale
heterostructures remains poorly understood. Here we uncover how exchange bias emerges in functional multiphase metal-
oxide nanoparticles by combining gas-phase synthesis, advanced
magnetic characterisation, and first-principles-informed
spin-dynamics simulations. Using Ni-Cr/NiO nanoparticles as a model system, we show that exchange bias is governed not simply by the presence of
ferromagnetic and
antiferromagnetic phases, but critically by their nanoscale spatial distribution and interfacial
topology. At 10 K, significant negative exchange bias (0.8 kOe) and coercivity enhancement (1.4 kOe) was exhibited; both decreased due to either Cr-segregation (at low Cr content) or to Cr accumulation inside the core (at high Cr content). The resulting competition between
magnetic phases produces a temperature-driven inversion from negative to positive exchange bias and a crossover from exchange-dominated to dipolar interactions. By linking density-functional-theory calculations directly to
spin-dynamics simulations of nanoparticle ensembles, we establish a predictive framework for designing exchange-coupled nanomagnets capable of operating beyond the superparamagnetic limit.
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All authors Murtaza Bohra, Stefanos Giaremis, Vidyadhar Singh, Joseph Kioseoglou, Stephan Steinhauer, Panagiotis Grammatikopoulos
Quantum Physics
Improving device-independent quantum key distribution protocols through multiple routed Bell tests
Sujan Vijayaraj and Mauro Paternostro
Device-independent
quantum key distribution (DI-QKD) guarantees security with a minimal set of assumptions about the experimental setup. The challenge posed by its implementation could be tackled using routed Bell tests with
entanglement swapping, or distant Bell state measurement (BSM) units. However, practical distances still require local tests with close-to-ideal violations or BSMs with high efficiency. We propose a DI-QKD protocol based on a multi-port BSM, and multiple sources and measurement devices, where in each round, routed tests are performed on randomly selected local devices. The violation of local Bell tests is checked even for the subset of rounds where successful BSM projections are achieved. By requiring that this violation remain consistent with the overall average, we specifically show improvements in the critical efficiencies of a three-port BSM, of up to $6\%$ in absolute terms for high visibilities. Without ideal violations, we also achieve arbitrarily small efficiencies with arbitrarily many BSM ports. Our approach enables long-distance DI-QKD, with access to highly efficient loophole-free routing setups, and multiple local tests (possibly imperfect) with very high local detection efficiencies. Remarkably, it avoids the use of
quantum memories and the need for long-range Bell tests. Finally, we extend the concept of routing to dimension witnesses, where
qubit-bounded sources send states to the BSM. This can be seen as a semi-device-independent extension of the aforementioned protocol.
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Nuclear Theory
Studying the QCD Matter produced in Heavy-Ion Collisions using the MUSES Calculation Engine
Johannes Jahan, Kevin P. Pala, Yumu Yang et al. (+42 more)
The equation of state of hot and dense matter is essential for describing heavy-ion collisions at all collision energies. Here, we explore the capabilities of the latest version of the MUSES Calculation Engine, $\textit{Calliope}$, focusing on software modules and workflows that compute the equation of state and observable properties of the matter produced in heavy-ion collisions. These include several equations of state, ranging from first-principles
lattice QCD to phenomenological approaches, with or without a critical point, and with phase-space dimensionality ranging from two dimensions defined by temperature $T$ and
baryon chemical potential $\mu_B$, to four dimensions after the addition of strangeness and electric-charge chemical potentials $\mu_S$ and $\mu_Q$. We also discuss modules that provide additional thermodynamic quantities and observables relevant for heavy-ion modeling, including elements of the pressure Hessian
matrix and transport coefficients. Workflow examples are constructed that merge two equations of state thermodynamically consistently to extend phase-diagram coverage, and feed the results into an equation of state inverter to produce inputs suitable for hydrodynamic simulations. Finally, we apply this framework to perform a relativistic viscous hydrodynamic simulation with equations of state with an extended $T$ and $\mu_B$ coverage and a movable critical point, including effects from transport coefficients that phenomenologically encode critical scaling, at collision energies $\sqrt{s_{NN}}=7.7, 19.6$, and $39$ GeV.
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All authors Johannes Jahan, Kevin P. Pala, Yumu Yang, Isabella Danhoni, Prachi Garella, Jonathan Gonzales, Joaquin Grefa, Mauricio Hippert, Surkhab Kaur Virk, Micheal Kahangirwe, Musa R. Khan, Feyisola Nana, Mateus Reinke Pelicer, Tulio E. Restrepo, Hitansh Shah, T. Andrew Manning, Mark Alford, Dekrayat Almaalol, Ahmed Abuali, Alexander Clevinger, Nikolas Cruz-Camacho, Carlos Conde-Ocazionez, Francesco Di Clemente, David Friedenberg, Hosein Gholami, Marco Hofmann, Jeremy W. Holt, Isaac Legred, Jamie M. Karthein, Toru Kojo, Konstantin Maslov, Paolo Parotto, Leonardo Pena, Grégoire Pihan, Christopher Plumberg, Roman Poberezhniuk, Romulo Rougemont, Jordi Salinas San Martín, Rajesh Kumar, Volodymyr Vovchenko, Veronica Dexheimer, Jorge Noronha, Jacquelyn Noronha-Hostler, Claudia Ratti, Nicolás Yunes
Astrophysics of Galaxies
Probing the molecular gas content of galaxies in an over-dense group at z~0.7: A test case for environmental quenching
Jonathan Freundlich, Benoît Epinat, Thierry Contini et al. (+14 more)
We investigated the impact of group environment on molecular gas reservoirs at an intermediate
redshift by observing the CO(2-1) emission from the
galaxy group COSMOS-Gr30 at $z \sim 0.7$ with the Institut de Radioastronomie Millimetrique (IRAM) NOrthern Extended Millimeter Array (NOEMA) and 30m
telescope. This dense environment, located at the intersection of large-scale
cosmic web filaments hosts a large ($\sim 10^{4}$ kpc$^{2}$) ionized gas structure revealed by MUSE. We detect CO emission in four
galaxies in the group with a signal-to-noise ratio (S/N) greater than five and derive upper limits for the remaining group members with secure spectroscopic
redshifts. Stacked measurements indicate that group
galaxies exhibit, on average, molecular gas contents reduced by $\sim 0.5$ dex relative to field scaling relations, corresponding to gas fractions that are $20- 40\%$ of those found in typical main-sequence
galaxies. Although the uncertainties are significant, this suggests that environmental processes efficiently deplete molecular gas reservoirs in the
galaxies of this group. The 30m observations place an upper limit on the molecular gas associated with the extended ionized structure, $M_{\rm gas} < 2 \times 10^{10} \rm M_\odot$, implying that less than a third of the gas in the intragroup medium is in a cold,
star-forming phase. Together, these results show how environmental mechanisms in dense group environments act to remove or suppress molecular gas within
galaxies, capturing quenching processes in action.
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All authors Jonathan Freundlich, Benoît Epinat, Thierry Contini, Philippe Salomé, Françoise Combes, Baptiste Jego, Davor Krajnović, Wilfried Mercier, Constanza Muñoz López, Matthieu Béthermin, Leindert Boogaard, Rodrigo Herrera-Camus, Diana Ismail, Fangzhou Jiang, Katarina Kraljic, Florent Renaud, Sandro Tacchella
High Energy Physics (Phenomenology)
Flavor Alignment and Mass Hierarchy: Doing Everything Scotogenically
Ernest Ma
Flavor alignment and mass hierarchy in
quarks are shown to be achievable together in a renormalizable theory using the dark sector, while keeping only the one
Higgs doublet of the standard model.
Quantum Physics
Aldo Lamarre and Dominik Šafránek
Autoencoders transformed classical machine learning by solving the curse of dimensionality, enabling principled weight initialization and learning compact, structured representations. In this work, we extend this paradigm to
quantum machine learning by introducing a variational autoencoder framework that learns task-specific
quantum embeddings of classical data. We demonstrate that high-dimensional
datasets, including ImageNet, can be compressed into a 13-
qubit quantum representation while remaining reconstructable through a learned decoder. On MNIST (3 vs 5), our approach achieves 98.5% validation accuracy using a
circuit-centric
quantum classifier, within 1.2 percentage points of a classical neural network baseline (99.7%) and more than 30 percentage points above a naive amplitude-
embedding approach. Unlike amplitude
embeddings, which require full
quantum state
tomography for recovery, or angle
embeddings, which generally rely on
circuit inversion under restrictive assumptions, the proposed framework reconstructs the original data from only a
polynomial number of measurements. The framework was further validated on IBM
quantum hardware, confirming that the learned
embeddings remain stable and reconstructable under real device noise.
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Optics
Fiber Bragg grating-based acoustic sensing system enabled by ML-trained, sub-picometer-tunable hybrid III-V/SiN lasers
Prabhav Gaur, Premanand Chandramani, Yossef Ehrlichman et al. (+7 more)
Distributed acoustic emission (AE) sensing is critical for early detection of structural degradation, yet conventional electrical sensors are difficult to scale and fiber-based approaches are limited by interrogation complexity and resolution. Here, we report an intelligent fiber Bragg grating (FBG) sensing system enabled by machine learning (ML)-trained hybrid III-V/SiN tunable
lasers that achieve uniform, mode-hop-free, sub-picometer wavelength control. A supervised gradient-descent
algorithm is used to learn the nonlinear electro-thermal tuning space of Vernier-based external-cavity
lasers, enabling continuous tuning with <0.1 pm resolution and <0.5 dB power variation. This capability allows precise
alignment to FBG reflection slopes for high-sensitivity acoustic detection. We demonstrate a four-
laser interrogation system monitoring 16 FBG sensors distributed across multiple metallic structures, operating over a 35 nm wavelength span. The system autonomously identifies sensor resonances, dynamically tracks spectral shifts, and reconfigures interrogation wavelengths in response to localized acoustic events. Using pencil-lead break tests as calibrated AE sources, we show simultaneous multi-channel detection and adaptive spatial localization. The combination of narrow linewidth (<10 kHz), wide tunability, and ML-driven calibration enables robust, scalable, and high-resolution sensing. This approach establishes a pathway toward fully autonomous, distributed photonic sensing networks for real-time structural health monitoring.
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All authors Prabhav Gaur, Premanand Chandramani, Yossef Ehrlichman, Mohammed Alshamari, Yufei Chu, Abu Mitul, John Simons, Ibrahim G. Yayla, Ming Han, Ashok V. Krishnamoorthy