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Physics Physics

physics Watch Physics

Friday 26 June

Applied Physics · Cross-listed from cond-mat.mtrl-sci

Unlocking Cryogenic Energy Storage by Constructing Dipole Glass with Unit-cell-level Polar Disorder

Yangyang Si, Denan Li, Yijie Li et al. (+21 more)

Cryogenic energy storage is vital for frontier technologies including deep-space exploration and quantum computing, yet conventional electrochemical energy systems fail below ~230 K due to frozen ion migration. While relaxor-based dielectric capacitors provide high efficiency at room temperature, the intrinsic freezing/growth of polar nanodomains at extended cryogenic regime limits their applications with deteriorated hysteresis losses. Here, we realize superior cryogenic energy-storage performance by designing unit-cell-level disordered dipole-glass state in Pb0.6Sr0.4ZrO3 thin films with composition near antiferroelectric-paraelectric phase boundary. The antiferroelectric-derived dipole-glass introduces enhanced unit-cell-level complexity of dipole interaction that suppresses long-range ferroelectric order. This enables ultralow-hysteresis operation (efficiency > 88%) down to 4 K, delivering record-high energy density (211 J/cm^3) at 9 MV/cm, stability over 10^8 charge/discharge cycles and microsecond-scale charge/discharge capability. This work establishes a dipole-glass paradigm for cryogenic dielectric capacitors, opening a new avenue to highly-efficient energy-storage systems with broad applications in frontier nanoelectronics.
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All authors Yangyang Si, Denan Li, Yijie Li, Changsheng Chen, Jingxuan Li, Chao Zhou, Hao Xiong, Tianfu Zhang, Wenjin Liao, Zhongqi Ren, Huaicheng Yuan, Dong Li, Jing-Kai Qin, Cheng-Yan Xu, Ye Zhu, Yunlong Tang, Sujit Das, Jieun Kim, Junling Wang, Hao Pan, Fei Li, Zhen Chen, Shi Liu, Zuhuang Chen

Atmospheric and Oceanic Physics

Ocean-atmosphere interaction at the Gulf Stream sea surface temperature front: variability and impacts on midlatitude atmospheric circulation

Luca Famooss Paolini

Sea surface temperature (SST) gradients associated with western boundary currents affect the atmospheric circulation across a range of spatial and temporal scales. Yet, several aspects of ocean-atmosphere interactions linked to oceanic fronts remain unclear. This PhD thesis analyses such interactions for the Gulf Stream SST front (GSF). The first part assesses the atmospheric response to the interannual GSF meridional shifts and its dependence on model horizontal resolution, using ERA5 reanalysis and atmosphere-only simulations forced by observed SST. Results show that the response is strongly resolution dependent, with only simulations finer than 50km resembling observed anomalies. Locally, diabatic heating near the GSF is mainly balanced by vertical motion and transient eddy heat transport. At large-scale, the GSF shifts is associated with a homo-directional shift in the North Atlantic eddy-driven jet and storm track, mediated by changes in low-level baroclinicity. The second part assesses the North Atlantic Oscillation (NAO)-GSF interaction and the mechanisms through which the NAO forces the GSF shifts on decadal timescale, using atmosphere and ocean reanalyses. The NAO and GSF covary on decadal timescales only during 1972-2018. This non-stationarity is also reflected in their lead-lag relationship: the NAO leads the GSF shifts by 3 years during 1972-1990 and by 2 years during 1990-2018. The lag is interpreted as the joint effect of the fast response of wind-driven oceanic circulation, the lagged response of deep oceanic circulation, and the propagation of Rossby waves. However, Rossby wave propagation is evident only before 1990, suggesting that its non-stationarity may explain the different NAO-GSF time lag before and after 1990. Overall, the thesis improves understanding of GSF variability and its role in North Atlantic and extratropical climate variability.
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Physics and Society

Extracting behavioural properties from face-to-face interactions temporal networks: a measure of egonet persistency

Gabriel Maurial, Elisa Klüger and Mathieu Génois

Understanding how individuals repeat social interactions over time is a central problem in the analysis of temporal networks. In social systems, repeated interactions shape processes such as information diffusion, collective coordination, and the emergence of social structure. Existing measures of egonet persistence often conflate genuine behavioural regularities with structural effects such as node degree, making it difficult to distinguish meaningful temporal correlations from random mixing. In this work, we introduce the Neighbourhood Persistency Criterion (NPC), a statistically grounded framework for quantifying egonet persistence across time. NPC combines classical similarity measures with tailored null models controlling for network topology and interaction weights. We apply this framework to high temporal resolution face-to-face interaction networks collected at four Computational Social Science conferences using the SocioPatterns platform. Our results reveal a common behavioural structure across events, characterised by an exploration$\unicode{x2013}$exploitation trade-off in social interactions. While many individuals alternate between both strategies, others exhibit stable interaction patterns throughout the event. Importantly, these behaviours show little systematic association with socio-demographic attributes, suggesting that interaction strategies are shaped primarily by contextual factors rather than stable individual traits. NPC thus provides a flexible and interpretable tool for studying egonet persistence in temporal networks and social systems.
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Plasma Physics

Collisionless dynamo seeds from phase mixing-induced electron slippage

István Pusztai, Lise Hanebring and James Juno

Magnetic fields permeating the Universe on the largest astrophysical scales are thought to result from dynamo amplification in weakly collisional turbulence, but the origin of the seed fields remains an open problem of cosmic magnetogenesis. We identify a kinetic mechanism for magnetic-field generation in initially unmagnetized, collisionless plasmas, arising from phase-mixing-induced braking of spatially varying electron flows. Using analytical theory, fully kinetic Vlasov simulations, and turbulent scaling arguments, we show that this process generates coherent magnetic seed fields on scales far larger than the characteristic kinetic scales of the plasma, with strengths comparable to or exceeding classical Biermann battery estimates. The mechanism requires neither a finite initial magnetic field nor misaligned thermodynamic gradients and occurs naturally in electron-ion plasmas.
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Atomic and Molecular Clusters · Cross-listed from cond-mat.quant-gas

Universality in strongly interacting bosonic clusters

L. Madeira, F. Pederiva and U. van Kolck

We develop an effective field theory (EFT) for strongly interacting bosonic clusters, using $^4$He as a paradigmatic example of universality in systems with large scattering length. At leading order (LO), two- and three-body zero-range interactions are entirely determined by the dimer and trimer ground-state energies. We show that ground-state energies for up to $N=15$ particles converge to cutoff-independent limits with extrapolation coefficients of natural size. At next-to-leading order (NLO), corrections stemming from the two-body interaction range and a four-body force, calibrated to the tetramer ground-state energy, reduce cutoff sensitivity. Close agreement with results from a realistic potential is found at LO and improved at NLO, demonstrating systematic convergence with few parameters at each order. The resulting EFT is directly applicable to larger clusters and bulk helium.
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Optics · Cross-listed from quant-ph

Detector-Conditioned Source-Space Nulls and Null-Mask Loss in a Programmable Two-Slit Interferometer

Jianming Wen

Afshar's double-slit experiment probes wave–particle complementarity by placing a wire grid at the dark fringes of a downstream interference pattern while retaining an imaging basis that appears to preserve which-path information. Here we propose and analyze a time-reversed Young–Afshar configuration in which the corresponding null test is transferred from the downstream field plane to the source-label plane of a time-reversed Young interferometer. In this reciprocal geometry, a point-addressable source illuminates a double slit, while the detector remains fixed. The observed fringe is therefore not a single-shot spatial intensity pattern, but a detector-conditioned response reconstructed by scanning the source coordinate. Consequently, a null in this pattern is not a node of a freely propagating field; it is a source label for which the coherent two-slit transfer amplitude to the selected detector vanishes. A mask placed at such source-plane labels is invisible to that detector when both slits are open, yet becomes visible when either slit is opened alone. We develop the scalar Fresnel model, derive the source-space null condition, introduce a detector-conditioned null-mask loss, and examine how this loss evolves under a tunable which-path marker. The source-space visibility and path distinguishability satisfy the standard duality relation, so no violation of complementarity is implied. The essential new feature is instead a reciprocal, detector-conditioned form of complementarity: Afshar's field-space transparency is replaced by response-function transparency in a reconstructed source basis.
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Optics · Cross-listed from cond-mat.mes-hall

A real-space exceptional ring mediates an eigenframe-charge transition in a non-Hermitian skyrmion

Kejun Liu

The integer topological charge of a skyrmion is the standard example of topological protection. We ask what happens to that protection when the local generator is made non-Hermitian by polarization-selective gain or loss. The texture charge of a smoothly evolving state remains homotopy-protected under the usual fixed-boundary condition: after projective normalization, the gain/loss contribution has the Gilbert relaxation form on the target sphere. The spectral charges of the local generator behave differently. Its biorthogonal eigenframe charge is quantized while the texture avoids exceptional points. At linewidth matching, the skyrmion equator becomes a real-space exceptional ring on which the biorthogonal Bloch field diverges, and the eigenframe class jumps from +1 to 0 in a parameter-driven spectral transition. The closed contour relies on constant splitting along the equator, or an equivalent design constraint; a partial or amplitude-anisotropic realization instead leaves isolated real-space exceptional points. We use an operational Jones parametrization of an isolated polarization doublet and give a Stokes-tomography reconstruction of the left-right frame. The result identifies a spatially resolved exceptional contour that mediates an integer transition of a real-space eigenframe charge.
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Applied Physics · Cross-listed from quant-ph

Industry-ready spin-photon interfaces for hybrid photonic quantum computing

Hêlio Huet, Hubert Lam, Thibaut Pollet et al. (+45 more)

Hybrid photonic quantum computers, combining stationary matter qubits and flying photonic qubits, offer an intrinsically networked and resource-efficient route to large-scale, error-corrected quantum computation. Their core components are cavity-coupled matter qubits that act as light–matter interfaces, enabling: high-efficiency on-demand single-photon generation, stable near-unity photon indistinguishability and spin–multi-photon entanglement. Semiconductor quantum dots in microcavities are a leading platform for realizing such devices. Yet reaching the performance, reproducibility and spin-coherence thresholds for large-scale error correction remains a major challenge requiring industrial fabrication and control. Here we report thousands of monolithic semiconductor quantum-dot devices fabricated using a III–V pilot production-line process compatible with large-scale deployment. Systematic control of source parameters yields state-of-the-art efficiency and supports a path to optical losses below fault-tolerance thresholds. Using field-quadrature state reconstruction as a stringent joint test of efficiency and indistinguishability, we observe near-unity photon quantum purity stable over tens of minutes and a record single-photon Wigner-function negativity. We further demonstrate seven-partite spin–multi-photon entanglement and spin coherence extendable to microsecond timescales in the low-magnetic-field regime. Finally, photons from distant sources are as indistinguishable as photons emitted successively by a single source. These results establish foundry-compatible III–V quantum dots as a scalable platform for hybrid photonic quantum computing.
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All authors Hêlio Huet, Hubert Lam, Thibaut Pollet, Petr Steindl, Alice Bernard, Albert Adiyatullin, Petr Stepanov, William Hease, Victor Guilloux, Nico Margaria, Joris Verstraten, Raksha Singla, Samuel T. Mister, Anton Pishchagin, Lara Couronné, Samuel Huber, David Sebastian, Duc Duy Tran, Thi Hao Nhi Nguyen, Thi Phuong Do, Joseph Sulpizio, Yann Portella, Kiarn T. Laverick, Thinhinane Bennour, Tomas Alexandre De Sousa, Davide Stefani, Mathias Pont, Maxime Descampeaux, Bianca Scaparra, Martin A. Jacobsen, Klaus D. Jöns, Rinaldo Trotta, Aristide Lemaître, Martina Morassi, Olivier Krebs, Loïc Lanco, Niels Gregersen, Alexia Auffèves, Maria Maffei, Shane Mansfield, Jean Senellart, Thomas Volz, Viviana Villafañe, Stephen C. Wein, Dario A. Fioretto, Sebastien Boissier, Thi Huong Au, Pascale Senellart

Fluid Dynamics

Statistical equilibria of two-dimensional turbulent flows for generic initial vorticity fields on a sphere, calculated on the basis of the original Miller-Robert-Sommeria theory

Koki Ryono and Keiichi Ishioka

Based on the original Miller-Robert-Sommeria theory, we explicitly compute a statistical equilibrium of two-dimensional turbulent flow on a sphere for a generic initial vorticity field introduced in a previous study. The macroscopic vorticity field corresponding to the obtained statistical equilibrium has a quadrupole structure. The resulting quadrupole structure is topologically consistent with the final state of the long-term time integration of the vorticity equation. However, the statistical equilibrium does not predict the formation of concentrated vortices as seen in the time integration. We also calculate statistical equilibria for the initial vorticity field with a planetary vorticity term, and find a change of statistical equilibria from quadrupole states to zonally symmetric states as the angular velocity of the sphere increases. The quadrupole statistical equilibria show nearly linear relations between the macroscopic vorticity and the macroscopic stream function, implying that higher-order Casimir invariants are virtually ineffective even when all Casimir invariants are considered. The discrepancy between the equilibria and the time integration results emphasizes the importance of mixing barriers, which prevent the relaxation of the evolving vorticity field to the statistical equilibria and allow the point-vortex-like dynamics of coherent vortices to persist.
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Fluid Dynamics

Optothermal Actuation of Unidirectional Thermo-osmotic Flows

Tetsuro Tsuji, Shota Suzuki, Satoshi Taguchi et al. (+2 more)

In this paper, we experimentally demonstrate the microscale direction control of thermoosmotic flows using a focused-laser heating. The key is the off-center laser irradiation on an immobilized light-absorbing microparticle, which generates a nonuniform, asymmetric heat source. The resulting thermo-osmotic flows are evaluated using the optically trapped particle tracking velocimetry (ot-PTV), presented in our preceding paper (T. Tsuji, et al., Physical Review Fluids 11, 034901 (2026)). It is shown that the flow characteristics can be modulated by the ionic strength of a sample solution and/or the surface molecular coating of the substrate. In particular, the significance of ionic strength on thermo-osmotic flows are discussed based on the surface potential of the substrate measured by frequency-modulated atomic force microscopy.
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All authors Tetsuro Tsuji, Shota Suzuki, Satoshi Taguchi, Haruya Ishida, Hideaki Teshima

Computational Physics · Cross-listed from math.NA

Analysis, thermodynamics, and a numerical solver for a pressure-temperature equilibrium closure of the four-equation model

Bennett Clayton, Joshua McConnell and Clell Solomon

We analyze an often used closure model for multi-material hydrodynamics where pressure-temperature equilibrium (PTE) is assumed for every state; emphasis is placed on tabular equations of state. This multi-material model is often referred to as the four-equation model. The identification of the admissible set is presented and is proven to be convex, setting the foundation for development of invariant-domain preserving methods for this model. A novel numerical method is presented for solving the highly nonlinear system for the equilibrated pressure and temperature with an arbitrary number of materials. This new method is compared with some traditional iterative solvers through a collection of different tests. Additionally, we provide a detailed analysis of the thermodynamics of the mixture model for general equations of state and prove existence and uniqueness of the pressure-temperature equilibrium solution under some thermodynamic assumptions.
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Optics · Cross-listed from cs.CV

VLM-Aware Meta-Optic Front-End Design for Frozen Vision-Language Models

Chanik Kang, Raphaël Pestourie and Haejun Chung

Conventional machine-vision pipelines typically rely on high-quality optics that produce clean, human-interpretable images, and optical design has therefore been driven by image-level criteria such as resolution, aberration correction, and pixel fidelity. However, such optics are often impractical for size-, cost-, or form-factor-constrained applications, where compact meta-optics offer an attractive alternative but operate under strict physical efficiency limits. We propose CODA, a co-design framework that optimizes a continuous-density meta-optic front-end for frozen-model recognition using differentiable image formation and adjoint-gradient updates of Maxwell-based simulations. CODA directly optimizes the cross-entropy loss of a fixed zero-shot CLIP classifier without learned reconstruction, image signal processing, or image-fidelity auxiliary objectives. In a two-dimensional simulated imaging benchmark on ImageNet-100, CODA improves CLIP ViT-L/14 zero-shot accuracy from 53.75 $\pm$ 3.57$\%$ with a focal-concentration baseline to 65.41 $\pm$ 3.99$\%$. The optimized optics further transfer without re-optimization across CLIP, SigLIP, and DINOv2 on ImageNet-100, CIFAR-100, and Food-101. These results demonstrate that, under constrained meta-optic imaging, downstream recognition can be improved by aligning optical design with frozen vision-model objectives rather than conventional image-formation criteria.
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Instrumentation and Detectors · Cross-listed from gr-qc

First Demonstration of Optical Feedback Control to Parametric Instability at Advanced LIGO

Juntao Pan, Carl Blair, Vladimir Bossilkov et al. (+5 more)

Increasing the circulating power in gravitational-wave detectors to the megawatt level is essential for future sensitivity improvement, but this is critically limited by optomechanical parametric instabilities. Current mitigation strategies are projected to be inadequate against instabilities when circulating power reaches a megawatt. Optical feedback offers a novel independent paradigm to mitigate parametric instability. In this Letter, we report the first demonstration of optical feedback control in a full-scale gravitational wave detector. We successfully suppressed an unstable mode at 10.428 kHz, reducing the parametric gain from R = 2 to R < 0.02. This work validates optical feedback control as an effective mitigation scheme for kilometre-scale interferometric gravitational-wave detectors, providing an effective strategy to allow detectors to reach the megawatt level.
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All authors Juntao Pan, Carl Blair, Vladimir Bossilkov, Jian Liu, Alex Adam, Chunnong Zhao, Li Ju, Anamaria Effler

Biological Physics

Self-organized robustness in mean-field interacting systems

Emmy Blumenthal and Gautam Reddy

Self-organization is a defining feature of living systems, with order often maintained through interactions between constituent units rather than centralized feedback. We introduce a tractable mean-field model of self-organized robustness, formulated as meta-optimization over the system's response to perturbations. The resulting interaction structure has an intuitive picture as a dynamically modulated landscape (“seascape”) whose shape is determined self-consistently to accelerate relaxation back to equilibrium. The collective dynamics follows an optimized Wasserstein gradient flow toward an attractor in the space of collective states. When communication is limited, interactions preferentially encode slowly relaxing modes and modes that are frequently perturbed. The model further shows that robust collective states are associated with flatter equilibrium landscapes and predicts a continuum of intermediate “reservoir states” in such systems. The model offers a perspective of self-organization as a hierarchical associative memory that operates on the scale of a collective of interacting computational units.
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Plasma Physics

Inferring solar-wind plasma structures from sparse probe trajectories using recurrent reduced-order learning

Maryam Reza and Farbod Faraji

In space plasma studies, spacecraft measurements often provide time histories of the solar-wind plasma. However, many heliospheric plasma processes are organized over spatial scales that cannot be directly resolved by limited local sampling. This creates a persistent challenge: how to use limited probe measurements to recover the spatial plasma distributions needed to interpret evolving solar-wind structures. In this work, we present a recurrent reduced-order learning framework to address this challenge. The method is demonstrated using WSA-ENLIL solar-wind simulation data to reconstruct two-dimensional meridional and equatorial fields from a small number of virtual probes, with radial velocity and plasma density considered as target quantities on both planes. From sparse temporal probe signals as inputs, the model recovers the dominant radial and latitudinal variations in the meridional plane and the spiral-shaped organization of the equatorial solar wind. It is also able to reconstruct spatial distributions of dynamically coupled plasma fields not directly sensed. Sensitivity studies are performed to assess the dependence of reconstruction accuracy on key parameters of the machine-learning framework: modal rank, number of probes, and input-history length. The outcomes underline the methodology's promise as a practical route for extracting spatial plasma-state information from spacecraft measurements in support of studies on the underlying physics of space and solar-wind plasmas.
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Fluid Dynamics

Interface tracking with Microscale Topological Surgery for two-dimensional filament breakup

Raaghav Ramani

We design and implement a Microscale Topological Surgery (MTS) algorithm to detect and enforce topological transitions in two-dimensional tracked interfaces. The method combines classical Lagrangian tracking with an intermittent topological processor that: (i) constructs Eulerian snapshots from which an interface family with microscale-resolved topology is extracted, (ii) infers adjacency topology between dual Lagrangian and Eulerian interface families, and (iii) performs interface surgery to stitch the two families together across microscale defect regions. A novel long-time nonlinear alternating-shear flow is introduced, in which repeated stretching and folding generate rich multiscale interface dynamics with filamentation at microscales. Using the MTS algorithm and a posteriori geometric and material diagnostics, we compute and visualize microscale filament-breakup dynamics. Error analysis and scaling studies demonstrate second-order geometric convergence and optimal computational scaling of the MTS algorithm, with topology-processing costs comparable to those of the underlying Lagrangian evolution. Ensemble simulations generated by pseudo-random perturbations of the flow further reveal coherent droplet size distributions and statistically robust filament-breakup dynamics.
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Optics

Enhancing Co-packaging Optics Enabled Silicon Photonics Security Assurance Hardware Fingerprinting

Liton Kumar Biswas, M Shafkat M Khan, Himanandhan Reddy Kottur et al. (+3 more)

Silicon photonics enables integration of optical components using standard semiconductor processes, greatly improving data communication bandwidth and energy efficiency. However, photonics integrated circuits (PICs) face unique security challenges, such as counterfeit or tampering threats, that conventional electronic security methods do not address. We propose a novel hardware fingerprinting technique that embeds two dimensional photonic crystal patterns into the density control filler regions of a PIC. Each PhC pattern is designed to resonate a specific visible to near infrared wavelengths, producing a distinctive optical signature (based on wavelength, polarization, and incident angle) for each device. Finite difference time domain (FDTD) simulation using ANSYS Lumerical is employed to optimize nanostructure dimensions and spacing so that each device's reflection/absorption spectrum contains unique narrowband peaks. No extra fabrication steps or materials are required beyond standard lithography, keeping costs low. The embedded nanostructures have sub-50nm precision, making forgery extremely difficult. Our method yields a high resolution, scalable fingerprint for silicon photonic chips, enabling cost-effective device authentication and improved supply chain security.
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All authors Liton Kumar Biswas, M Shafkat M Khan, Himanandhan Reddy Kottur, Hao Wang, Hamed Dalir, Navid Asadizanjani

Thursday 25 June

Popular Physics

Improving Punching "Power": Reconsidering the roles of initial strike velocity and effective mass

Joseph L. Natale

We review the principal features of one-dimensional, elastic collisions pertinent to modeling strike-mediated impacts in martial arts and combat sports contexts. Arguing for the post-collision velocity of a stationary, target mass as a useful proxy for determining overall punch efficacy, we demonstrate that pre-collision velocities for real strikes are bounded, such that speed prior to impact has a more limited effect on the impulse experienced by said target than suggested by supporting literature. We find that the value of incoming, "effective" mass – despite eluding uniform establishment criteria or measurement protocols across the same body of literature – exerts an independent influence on the target velocity which can, in principle, match or exceed that of the strike speed. We perform explicit numerical analyses to supplement these theoretical considerations, in dynamical regimes relevant to real human combat, and then briefly discuss the potential for a given fighter to attain a fold-increase in effective mass (from a reasonable baseline value based on bodyweight, and supported by previous work) sufficient to realize limits for upper-limb strikes to the body, in practice, as a trainable goal.
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Computational Physics · Cross-listed from cs.LG

Diffusion-corrected Autoregressive Fourier Neural Operator for Droplet Evolution Prediction

Jinghao Cao, Minsung Kang, Hongyue Sun et al. (+5 more)

Predicting droplet evolution in material jetting, or Inkjet Printing (IJP), is essential for maintaining printing quality. However, long-horizon forecasts remain challenging due to error accumulation and the complex coupling of process variables. In this work, we introduce the Diffusion-corrected Auto-Regressive Fourier Neural Operator (DiffARFNO), a two-stage framework that combines an autoregressive Fourier-MIONet with a conditional Denoising Diffusion Implicit Model (DDIM) corrector. Fourier-MIONet is trained as a coarse predictor and deployed autoregressively for long-horizon forecasting. In the second stage, a DDIM-based conditional corrector refines the coarse prediction within each sliding window through efficient iterative denoising. By combining coarse predictions from Fourier-MIONet with a DDIM corrector that restores fine details, DiffARFNO aims to provide high-fidelity predictions for long-horizon forecasts. Extensive experiments on droplet datasets from ANSYS Fluent demonstrate that DiffARFNO significantly outperforms existing state-of-the-art models.
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All authors Jinghao Cao, Minsung Kang, Hongyue Sun, Chi Zhou, Jihoon Chung, Xubo Yue, Sanchoy Das, Bo Shen

General Physics

Dynamical dark energy in the Bianchi Type-V Universe with DESI DR2 BAO, SNIa compilation and RSD measurements

Shambel Sahlu, Álvaro de la Cruz-Dombriz, A. H. A. Alfedeel et al. (+2 more)

We investigate the cosmological implications of dynamical dark energy (DDE) models within an anisotropic, spatially homogeneous Bianchi Type-V spacetime framework using a $1+3$ covariant thermodynamics approach. By implementing both constant ($w$) and time-varying ($w_0, w_a$) parameterized equations of state, we evaluate the background expansion history and track linear matter perturbations via the quasi-static approximation. We confront these scenarios with the latest cosmological datasets, including the Dark Energy Spectroscopic Instrument (DESI) DR2 Baryon Acoustic Oscillations (BAO), the Union3 and Dark Energy Survey 5-year (DESY5) Type Ia Supernovae compilations, Cosmic Chronometers (CC), and Redshift-Space Distortion (RSD) measurements. Our joint statistical analyses reveal that the introduction of spatial anisotropy coupled with DDE efficiently accommodates recent late-time measurements and provides a viable mechanism to mitigate the persistent $H_0$ and $S_8$ cosmological tensions. Model selection metrics show that while Akaike criteria strongly support the extended Bianchi Type-V scenarios across most joint data combinations, Bayesian criteria continue to favor the simpler standard $\Lambda$CDM baseline due to its lower dimensionality. Finally, we establish tight constraints on the current matter density parameter $\Omega_{m,0}$, the shear parameter $\Omega_{\sigma,0}$, and the dark energy evolution parameters, confirming that anisotropic extensions remain viable and testable frameworks for modern precision cosmology.
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All authors Shambel Sahlu, Álvaro de la Cruz-Dombriz, A. H. A. Alfedeel, Gonzalo J. Olmo, Amare Abebe

Instrumentation and Detectors

CUORE Data Release for ML Applications: Pulse Shape Analysis Dataset

CUORE Collaboration

We present a public dataset from the CUORE (Cryogenic Underground Observatory for Rare Events) experiment, designed to support the development and benchmarking of Artificial Intelligence and Machine Learning (AI/ML) algorithms for cryogenic calorimeter data analysis. CUORE uses TeO$_2$ cryogenic calorimeters to measure particle energy depositions as thermal fluctuations. This dataset contains thermal pulses measured during calibration data taking. Each data point is provided as a one-dimensional, time-series array corresponding to a thermal pulse, accompanied by a binary classification label to distinguish between single-pulse events and pile-up events with two or more pulses; pulse normalization parameters and relevant metadata are also included, with all data stored in HDF5 format. This data release enables the testing of supervised learning approaches to pulse shape analysis, pile-up identification, and related tasks in the context of rare-event searches with cryogenic calorimeters.
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General Physics

Another one bites the dust – how red supergiants keep surprising us

Jacco Th. van Loon

Extreme red supergiant WOH G64 has led researchers a merry dance these last few years, but what does it reveal about the secret lives of these beasts? This article sets the latest observations of WOH G64 in the context of what has been observed in other supergiants such as Betelgeuse and what we are learning from the massive stars that have been identified to explode as a supernova.
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Data Analysis and Statistics · Cross-listed from cond-mat.stat-mech

Comparison of different exact generalized Langevin equations with a non-linear potential of mean force and an observable-dependent mass and friction

Benjamin J. A. Héry, Lucas Tepper and Roland R. Netz

The Mori-Zwanzig projection formalism constitutes a powerful and robust framework for deriving equations of motion in terms of generalized Langevin equations (GLEs) for an arbitrary observable using evolution and projection operators. Based on this framework, we analyze the properties of four distinct GLEs for a scalar observable including a Markovian force derived from a generally non-linear potential, a non-Markovian friction force, and an orthogonal force, commonly interpreted as a random force. While all four GLEs are exact, they differ in the memory friction kernel, which may either be dependent or independent of the observable, and by the potential, which may either include or exclude the effective kinetic energy of the observable. Inclusion of the kinetic energy in the potential is advantageous for observables whose velocity satisfies Wick's theorem, since this reproduces the correct distribution of the observable and its velocity even without contributions from the friction force and the orthogonal force.
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Biological Physics · Cross-listed from q-bio.QM

Metabolic scaling, von Bertalanffy growth and an exponent equation

Hana Krakovská, Klaus Stiefel and Rudolf Hanel

In this work, we interpret developmental growth as a metabolic energy allocation problem and link the von Bertalanffy growth model to metabolic energy investments into the growth channel. Using a framework that specifies how metabolic energy is allocated among baseline maintenance, growth, and other processes, we analyse the resulting growth allocation patterns and derive direct relationships between key scaling exponents: the mass-growth exponent, the length-based exponent, the metabolic scaling exponent, and the geometric exponent, which describes the mass-length relationship. These exponents determine the metabolic investment exponent, which controls the qualitative behaviour of the growth-allocation function. Requiring the inferred allocation fraction to remain biologically feasible, we derive constraints on developmental velocity and characteristic mass scales. This provides a physical, energy-based interpretation of phenomenological growth curves and clarifies how metabolic scaling, geometric scaling, and growth dynamics are interrelated within a single allocation framework.
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Fluid Dynamics

Toward a Universal Framework for the Internal Gravity Wave Spectrum

Leticia Fabre-Lima, Jeffrey Early and Miles A. Sundermeyer

The Garrett-Munk (GM) spectrum has long provided a canonical model of the oceanic internal gravity wave field. However, it relies on hydrostatic assumptions and idealized stratification that limit its applicability where non-hydrostatic dynamics, vertical boundary effects, or non-monotonic stratification are important. Here we develop a generalized framework for the internal wave spectrum based on non-hydrostatic vertical modes formulated in horizontal wavenumber-vertical mode space. Energetic orthogonality among wave modes requires that such a formulation be cast in horizontal wavenumber space rather than frequency space. In this formulation, the deformation radius associated with each vertical mode provides a proxy for distinguishing hydrostatic and non-hydrostatic regimes. Vertical modes are obtained numerically from the fixed-K Sturm-Liouville problem, allowing arbitrary stratification and multiple turning depths. Combined with a generalized spectral function, the formulation yields expected distributions of horizontal kinetic, vertical kinetic, and potential energy as functions of depth, frequency, and horizontal wavenumber. Example applications illustrate departures from GM theory associated with boundary effects and non-hydrostatic dynamics, including improved representation of vertical variance and high-frequency vertical kinetic energy, while reproducing observed features of horizontal wavenumber spectra.
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Optics · Cross-listed from astro-ph.IM

Laboratory characterization of a multi-photonic lantern optical waveguide using off-axis holography

Aditya R. Sengupta, Benjamin L. Gerard, Dominic Sanchez et al. (+7 more)

Photonic lanterns (PLs) are waveguides that convert multi-mode input light to single-mode outputs. Wavefront sensing (WFS) and spectroscopy using a PL have been demonstrated, but PL simulations and experiments show significant mismatches. For the WaveDriver project, a proposed Habitable Worlds Observatory pathfinder that uses a PL for WFS as well as for integral field spectroscopy, we manufactured an optical waveguide consisting of an array of seven 19-port PLs in one device. We present laboratory characterization of the individual PLs, consisting of measurements of the principal modes at each PL input using digital off-axis holography. We compare our mode measurements to simulations to assess the variation in the PL manufacturing process. We discuss expected WFS performance in the WaveDriver configuration.
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All authors Aditya R. Sengupta, Benjamin L. Gerard, Dominic Sanchez, Matthew DeMartino, Rebecca Jensen-Clem, Kevin Bundy, Michael J. Messerly, Paul Pax, Daren Dillon, Eric Strang

Optics · Cross-listed from astro-ph.IM

Experimentally-determined performance limits for joint imaging and wavefront sensing with a photonic lantern

Aditya R. Sengupta, Vincent Chambouleyron, Rebecca Jensen-Clem et al. (+16 more)

The photonic lantern (PL) is a focal-plane wavefront sensor (WFS) that can be used for second-stage control of extreme adaptive optics (AO) systems. While the number of sensed modes and the dynamic range with respect to each mode have been relatively well characterized, little attention has been paid to the PL's sensitivity, i.e. how measurement noise impacts the accuracy of PL wavefront reconstruction. We compute the PL's sensitivity to photon noise as a function of spatial frequency, and compare it to existing WFSs, using simulations as well as experiments on the muirSEAL testbed. We further assess these metrics in the case where only a subset of PL ports are available for wavefront sensing. In this configuration, the remaining ports are used to spatially and spectrally reconstruct the observed scene using algorithms such as SPADE. Using more ports for wavefront sensing enables greater aberration sensitivity but leaves less spatial information for image reconstruction. This allows us to trade off between fewer samples with smaller aberrations and more samples with larger aberrations. This work sets the stage for AO system design incorporating the PL as a joint WFS and imager.
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All authors Aditya R. Sengupta, Vincent Chambouleyron, Rebecca Jensen-Clem, Emiel Por, Benjamin L. Gerard, Jordan Diaz, Zoe Weber-Porter, Yoo Jung Kim, Steph Sallum, Matthew DeMartino, Daren Dillon, Kevin Bundy, Anna K. Gagnebin, Philip Hinz, Caleb Dobias, Tara Crowe, Stephen S. Eikenberry, Rodrigo Amezcua-Correa, Stephanos Yerolatsitis

Fluid Dynamics

Two-Dimensional Locally Adaptive Non-Hydrostatic Extension of Shallow Water Equations

Kemal Firdaus and Jörn Behrens

We introduce a two-dimensional non-hydrostatic model for shallow water wave dispersion. The model is based on a locally adapted application of a non-hydrostatic correction to the hydrostatic shallow water equations (SWE) in a predictor-corrector scheme. Applying the non-hydrostatic correction uniformly to the entire domain demands a high computational cost, since an elliptic system of equations needs to be solved for the correction terms. We demonstrate that by determining the area where the non-hydrostatic effects are significant, and applying the correction only locally, the computational effort can be reduced by approximately 40% without sacrificing accuracy in tsunami-like scenarios. As indicators for the non-hydrostatic effect, we use the ratio between total water depth and surface elevation, as well as horizontal velocity norms. Results are shown for several well-known test cases, including wave trains over a semi-circular shoal, static, and moving bottom tsunami-like wave propagation.
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Fluid Dynamics

The multifractal nature of turbulent energy dissipation

Charles Meneveau and K.R. Sreenivasan

The intermittency of the rate of turbulent energy dissipation ${\epsilon}$ is investigated experimentally, with special emphasis on its scale-similar facets. This is done using a general formulation in terms of multifractals, and by interpreting measurements in that light. The concept of multiplicative processes in turbulence is (heuristically) shown to lead to multifractal distributions, whose formalism is described in some detail. To prepare proper ground for the interpretation of experimental results, a variety of cascade models is reviewed and their physical contents are analysed qualitatively. Point-probe measurements of ${\epsilon}$ are made in several laboratory flows and in the atmospheric surface layer, using Taylor's frozen-flow hypothesis. The multifractal spectrum $f({\alpha})$ of ${\epsilon}$ is measured using different averaging techniques, and the results are shown to be in essential agreement among themselves and with our earlier ones. Also, long data sets obtained in two laboratory flows are used to obtain the latent part of the $f({\alpha})$ curve, confirming Mandelbrot's idea that it can in principle be obtained from linear cuts through a three-dimensional distribution. The tails of distributions of box-averaged dissipation are found to be of the square-root exponential type, and the implications of this finding for the $f({\alpha})$ distribution are discussed. A comparison of the results to a variety of cascade models shows that binomial models give the simplest possible mechanism that reproduces most of the observations. Generalizations to multinomial models are discussed.
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Medical Physics

Ridge-filter crosstalk in conformal proton FLASH planning: dependence on beamlet pitch and iterative mitigation

Zongsheng Hu, Yuting Li, Henry Meyer et al. (+5 more)

Objective: Patient-specific ridge filters (PSRFs) can enable conformal single-energy proton FLASH delivery without energy switching. However, converting optimized spot-based dose distributions into physically adjacent ridge-filter structures may introduce inter-beamlet modulation errors not captured by conventional isolated-spot optimization. This study characterized ridge-filter (RF) crosstalk, evaluated its dependence on the beam-width-to-pitch relationship, and developed an iterative mitigation strategy. Approach: A Monte Carlo dose influence matrix was generated for monoenergetic proton beamlets passing through RFs of varying thickness. A baseline spot-weighted IMPT plan was optimized to meet dose constraints and converted into PSRF geometries. PSRF dose distributions were calculated by explicitly modeling the PSRF in the scanned beam path. RF crosstalk was quantified by comparing PSRF and baseline IMPT plans. Lateral beamlet spacings of 8, 10, 12, and 15 mm were evaluated using gamma analysis, DVH metrics, and mean relative dose difference. An iterative re-optimization method was tested in water-phantom and patient CT geometries. Results: RF crosstalk produced hot and cold spots, reducing agreement between PSRF and baseline IMPT plans. For the same spot size and target geometry, crosstalk increased as beamlet spacing decreased. Iterative re-optimization substantially reduced dose discrepancies, lowering the mean relative dose difference in the target from 8.9% to 3.4% in water and from 3.7% to 1.8% in CT. Significance: RF crosstalk is an important source of dose inconsistency in ridge-filter-based conformal proton FLASH planning. Its dependence on the beam-width-to-pitch relationship and mitigation through iterative re-optimization provide a practical framework for improving the accuracy and robustness of patient-specific single-energy proton FLASH delivery.
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All authors Zongsheng Hu, Yuting Li, Henry Meyer, Xiaochun Wang, Susan L. McGovern, Emil Scheueler, Radhe Mohan, Uwe Titt