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2603.10120 2026-03-12 astro-ph.HE astro-ph.IM gr-qc

On the angular localization of gravitational-wave signals by pulsar timing arrays

Stephen R. Taylor

Comments 14 pages, 9 figures

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We provide a complete study of the factors influencing gravitational-wave signal localization using pulsar timing arrays. We derive analytical expressions for the Cramér-Rao sky localization precision that delineate the impact of the angular proximity, $ξ$, between the pulsar and the gravitational wave source, and the precision, $σ_L$, with which pulsar distances are known. Interference between the Earth and pulsar terms creates rapid angular oscillations for sky-coordinate Fisher matrix elements that aids localization, which is complemented by more broadly varying antenna response gradient information. The relative importance of these factors depends on whether pulsar distances are known precisely [i.e., $σ_L\leqλ_\mathrm{GW}/(1-\cosξ)$] or imprecisely, respectively. If the former, tightening pulsar distance precisions improves signal localization according to $ΔΩ_\mathrm{sky}\proptoσ_L^2$ until the Earth-pulsar system reaches its diffraction limit. If the latter, localization precision is degraded, but more pulsars in close proximity to the source is the best means of improving. With $α$ indexing pulsars, this scales as $ΔΩ_\mathrm{sky}~\propto~(\sum_α\mathrm{SNR}_α^2/ξ_α^2)^{-1}$ in the small-angle limit of the unmarginalized Fisher matrix, and we derive the analytic generalization to any angle between a pulsar and the source. Finally, we study a scenario where pulsar-term phases are treated as nuisance variables that are unconnected to binary or PTA properties. This phase-decoupled scenario, which is how all PTA continuous wave searches are currently conducted, delivers localization performance similar to the antenna-response--driven case, and does not exhibit significant improvement as pulsar distance precisions are tightened.

2603.10119 2026-03-12 quant-ph cond-mat.quant-gas

Digital dissipative state preparation for frustration-free gapless quantum systems

Johannes Feldmeier, Yu-Jie Liu, Mikhail D. Lukin, Soonwon Choi

Comments 5 + 18 pages

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Preparing algebraically correlated ground states of quantum many-body systems is an important, yet challenging task for quantum simulation. We introduce a protocol that employs local projective measurements and unitary feedback for frustration-free gapless systems. Our approach prepares a priori unknown ground states in time that scales polynomially with system size. We analytically show the performance our protocol for the dynamics of a single-particle; we argue the same mechanism generalizes to many-body systems based on the physics of quasiparticles. Our theory predicts that a transient cooling dynamics directly reveals the system's universal critical properties. In particular, the state preparation time is linear in the inverse of the finite-size gap (up to log correction) when the system's dynamical critical exponent is larger or equal the effective spatial dimension explored by the quasiparticles. We verify these predictions in numerical simulations of ferromagnetic Heisenberg models in one- and two dimensions, a Fredkin spin chain, and a two-dimensional model of resonating valence bond states. Our protocol stabilizes gapless many-body ground states fully digitally without requiring analog rotations, enabling access to high-fidelity states beyond conventional adiabatic approaches in near-term experiments.

2603.10118 2026-03-12 astro-ph.GA

A Statistical Framework to Identify Kinematically Outlying LMC Globular Clusters and Implications for the LMC's Dark Matter Profile

Tamojeet Roychowdhury, Navdha, Himansh Rathore, Knut A. G. Olsen

Comments 21 pages, 5 figures, submitted to The Astrophysical Journal

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The LMC's Globular Clusters (GCs) bring a novel opportunity to understand the LMC's assembly history and dark matter (DM) properties, provided the kinematically outlying GCs can be reliably identified. However, traditional diagnostics like the Energy-Angular Momentum space fail because of large uncertainties on the GC velocities. In this work, we develop a new, robust statistical framework for identifying kinematically outlying LMC GCs, by using their Gaia-DR3 Proper Motions (PMs) combined with previous Line-of-Sight (LoS) velocity measurements. We use the difference between a GC's velocity vector and the average velocity vector of the surrounding red clump stars as a metric for quantifying a GC's kinematic peculiarity. We account for both the velocity measurement uncertainties and the LMC's intrinsic velocity dispersion. We find 5 LMC GCs to be kinematically outlying based on PM differences alone, and additional 6 GCs if LoS velocity information is also used. Majority of the GCs with outlying PMs are clustered at a distance of 3-4 kpc from the LMC center. The inclusion of outlying LMC GCs introduces a bias of upto 30% in the LMC's enclosed mass estimates derived using GCs as dynamical tracers; caution must be exercised in choosing the GC sample for precisely determining the LMC's DM content. We discuss the possibility that the kinematically outlying LMC GCs may have been accreted from external galaxies, and motivate future spectroscopic follow-up of the GC population to better understand the assembly history of massive satellite galaxies of Milky Way like hosts.

2603.10117 2026-03-12 hep-th

Entanglement and Renormalization Group Irreversibility of Quantum Field Theory in AdS

Nicolás Abate, Ignacio Salazar, Gonzalo Torroba

Comments 35 pages, 12 figures

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We study nonperturbative aspects of quantum field theory (QFT) in rigid anti de Sitter (AdS) spacetime using quantum information theoretic methods. While irreversibility of renormalization group (RG) flows is well established in flat space, it is not obvious whether it persists in AdS, where negative curvature and an asymptotic timelike boundary significantly modify infrared dynamics. Using strong subadditivity and AdS invariance, we derive an entropic second-order differential inequality for the difference between the vacuum entanglement entropy of a QFT and that of its ultraviolet fixed point, evaluated for spherical bulk regions. This inequality allows us to define RG charges that measure the relevant number of degrees of freedom, and we prove the irreversibility of the RG in $2,\,3,$ and $4$ spacetime dimensions. We further analyze free scalar and fermion theories in AdS, developing lattice formulations adapted to the geometry and computing entanglement entropies and RG charges. In AdS$_2$, we obtain analytic results for a massive Dirac fermion and compare them with numerical lattice calculations. These examples illustrate the general irreversibility theorem and clarify the distinction between conformal and massive theories in AdS.

2603.10116 2026-03-12 gr-qc

Adiabatic evolution of asymmetric binaries on generic orbits with new fundamental fields I: characterization of gravitational wave fluxes

Sara Gliorio, Matteo Della Rocca, Susanna Barsanti, Leonardo Gualtieri, Andrea Maselli, Thomas P. Sotiriou

Comments 33 pages, 25 figures, 5 tables

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We investigate the dynamics of asymmetric binaries in extensions of General Relativity featuring a massless scalar field non-minimally coupled to gravity, focusing on the interplay between eccentricity and inclination in fully generic bound orbits. Building on an effective field theory framework tailored to extreme- and intermediate-mass-ratio inspirals, we compute scalar-field perturbations using a new arbitrary-precision C++ code capable of evolving perturbations along generic Kerr geodesics, STORM. We investigate the complete set of scalar fluxes at infinity and through the horizon across the relevant parameter space and analyze their harmonic structure as a function of orbital geometry and black-hole spin. Our results advance ongoing efforts to construct accurate waveform models for asymmetric binaries beyond GR and lay the groundwork for precision tests of fundamental physics with next-generation gravitational-wave detectors.

2603.10115 2026-03-12 hep-ph hep-th

Production of global vortices with quantum mediation

Omer Albayrak, Tanmay Vachaspati

Comments 9 pages, 8 figures with subfigures

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We study global vortex production in (numerical) scattering experiments when the scatterer and the vortex degrees of freedom interact only due to intermediary quantum variables. We work in $2+1$ dimensions with a complex scalar field, $ϕ$, that supports global vortices, a real scalar field, $ψ$, that is the scatterer, and a quantum field, $ρ$, that couples to both $ϕ$ and $ψ$, acting as a mediator. We simulate the scattering of relativistic Gaussian wavepackets of $ψ$ and scan parameter space for regions where vortex-antivortex pairs are produced. The results show that vortex production is highly sensitive to the initial Gaussian parameters, and the parameter space is chaotic with ``holes" and isolated regions of vortex production.

2603.10114 2026-03-12 hep-ph astro-ph.CO

Stodolsky effect in the framework of Generalised Neutrino Interactions

Siddhartha Bandyopadhyay, Ujjal Kumar Dey

Comments 24 pages, 4 figures, 2 tables

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We study the Stodolsky effect utilizing the most general form of neutrino interactions with electrons below the electroweak scale by considering all possible Lorentz invariant operators respecting SU(3)$\otimes$U(1) symmetry. We perform our calculation for both Dirac and Majorana neutrinos and find that in the most general setting, only the non-standard neutrino interactions and the tensor interaction terms provide a non-zero contribution, apart from the Standard Model contribution. We investigate the implications for the possible detection of the cosmic neutrino background (C$ν$B) by analysing the energy shifts that are characteristic of the Stodolsky effect. We also discuss the implication of considerable asymmetry in the C$ν$B on the present scenario.

2603.10113 2026-03-12 astro-ph.CO

Steeling Weak Lensing Source Galaxy Samples against Systematics using Wide Field Spectroscopy

Joseph DeRose, Noah Weaverdyck, Martin White, Shi-Fan Chen, David Schlegel, Anže Slosar

Comments 35 pages, 14 figures, 2 appendices

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We investigate the cosmological constraining power of combined weak galaxy lensing and galaxy clustering probes, i.e. $3\times2$-point analyses, assuming flexible models for redshift uncertainty, and Lagrangian perturbation theory and hybrid effective field theory models for galaxy intrinsic alignments, galaxy bias and baryonic physics. In this context, we provide a detailed accounting of the limiting systematics on $3\times2$-point analyses. Our main finding is that in the presence of current levels of uncertainty on baryonic physics, the information content of weak lensing analyses saturates on quasi-linear scales, allowing the use of source galaxy samples that are significantly less dense, e.g. with number densities of $5\rm \, arcmin^{-2}$, without sacrificing constraining power, provided that redshift distributions can be calibrated at the $σ(\langle z\rangle)=0.005$ level. We show that for sufficiently narrow lens and source redshift distributions, intrinsic alignment contributions can be largely self-calibrated, though sufficient flexibility must be given to the redshift and scale dependence of this signal. The near optimality of such relatively sparse source galaxy samples opens the possibility to directly calibrate the redshift distributions and intrinsic alignment contamination of such a sample using a spectroscopic instrument like DESI, thus mitigating the dominant systematics in weak lensing analyses.

2603.10112 2026-03-12 cond-mat.str-el cond-mat.stat-mech

Classical Kitaev model in a magnetic field

Paul A. McClarty, Roderich Moessner, Karlo Penc, Jeffrey G. Rau

Comments 16 pages, 12 figures

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Motivated by experiments on spin-orbit coupled magnets with Kitaev exchange in magnetic fields, we present an analysis of the classical Kitaev honeycomb model in the presence of a magnetic field. We show that there is a spin liquid regime that exists within a finite window of fields from zero up to a finite threshold before transitioning into the polarized paramagnet. We uncover constraints that spins need to satisfy in the ground state and show that they determine the exact limiting zero temperature behavior of the heat capacity and magnetic susceptibility within the spin liquid as a function of field. When the field is finite, both the two-point spin and the quadrupolar correlations are short-ranged, in contrast to the zero-field case. We rationalize an effective mass for the quadrupolar correlations in terms of a coarse-grained theory with fluctuating effective charge degrees of freedom. Finally, we show that weak site-dilution does not change the magnetization within the spin liquid -- a kind of "perfect" compensation of the site dilution.

2603.10111 2026-03-12 astro-ph.HE

XMM-Newton Observations of Flares and a Possible Pulse Dropout in the Supergiant X-ray binary 4U 1909+07

Joel B. Coley, Ralf Ballhausen, McKinley Brumback, Robin H. D. Corbet, Camille M. Diez, Felix Fuerst, Nazma Islam, Gaurava K. Jaisawal, Peter Kretschmar, Christian Malacaria, Katja Pottschmidt, Pragati Pradhan

Comments 18 pages, 9 figures, 3 tables, accepted for publication in The Astrophysical Journal on 2026 March 6

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We report on a pair of X-ray Multi-Mirror Mission (XMM-Newton) observations of the Supergiant X-ray binary 4U 1909+07, which were performed on 2021 October 3 and 2021 October 8, respectively. We measure the neutron star rotation period in each observation to be $\sim$602.62 s. This continues a long spin-up trend that has persisted since 2001 where the neutron star spin period was found to be $\sim$604.66 s. In our timing analysis, we observe strong variations in the amplitude of the 1--10 keV pulse profile as a function of time, and for the first time we find a low flux interval extending for a single pulse period in which pulsations are no longer detected. We interpret this low flux interval as a pulse dropout similar to those observed in Vela X-1 and GX 301-2, which were each explained by a low-density cavity in the wind driving the propeller effect. In our time-resolved spectral analysis, we observed the spectral continuum, which can be described as an absorbed power law modified by a high-energy cutoff, to significantly soften during the pulse-dropout phase. No evidence of an increasing absorption column density was found. The observed softening in 4U 1909+07 also supports an interpretation that the observed pulse dropout may be driven by the propeller effect, but the quasi-spherical settling accretion regime cannot be ruled out.

2603.10110 2026-03-12 gr-qc hep-th

Regular Geometries from Singular Matter in Quasi-Topological Gravity

Pablo Bueno, Robie A. Hennigar, Ángel J. Murcia, Aitor Vicente-Cano

Comments 28 pages, 3 figures

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Vacuum quasi-topological gravity with infinitely many terms in the action satisfies Markov's limiting curvature hypothesis: the spherically symmetric solutions are regular and all curvature invariants are bounded by solution-independent scales. We study how this picture changes when the theory is coupled to matter. We find that minimally coupled matter spoils the scaling properties of the vacuum equations that lead to the validity of Markov's hypothesis, but the corresponding geometries often remain regular. We make this precise by developing a set of sufficient conditions on general static, spherically symmetric stress-tensors such that the corresponding solutions have bounded curvature. These conditions cover regular matter sectors but also singular matter profiles that are sufficiently singular in a sense we quantify. Our conclusions hold independently of the matter field equations and include configurations in which matter exhibits divergent energy density and pressure at finite radius or at Killing horizons, results that may have implications for mass inflation in these models. We then explore non-minimal couplings, focusing on theories with infinite towers of higher-curvature and electromagnetic terms in the action. In this class, Markov's hypothesis can be restored: we present theories admitting a universal upper bound on curvature, independent of the mass and charge. Overall, our results highlight subtleties in coupling quasi-topological gravity to matter and suggest Markov's hypothesis as a potential selection criterion for resummed gravity-matter effective theories.

2603.10105 2026-03-12 physics.chem-ph physics.comp-ph quant-ph

Localized intrinsic bond orbitals decode correlated charge migration dynamics

Imam S. Wahyutama, Madhumita Rano, Henrik R. Larsson

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For decades, scientists have studied the intricate charge migration dynamics, where after ionization a localized charge distribution ("hole") migrates across the molecule on a femtosecond timescale. This has the potential for controlling electrons in molecules, yet a comprehensive understanding of the many aspects of charge migration is still missing. In this work, we analyze charge migration using an extension of localized intrinsic bond orbitals (IBOs). These orbitals lead to a compact representation of the dynamics and map the complex, correlated many-electron charge migration to chemical concepts such as curly arrows and orbital-orbital interactions. By analyzing multiple challenging scenarios, we show how IBOs enable us to identify key mechanisms in charge migration. For example, we show that different mechanisms are responsible for converting a $π$-shaped hole to a $σ$-shaped hole and vice versa. We explain these in terms of hyperconjugation interactions and configurations that couple orbitals with different symmetries. We further demonstrate how IBOs can be used to find molecules with high charge migration efficiency. We carry out all simulations using an efficient set up of the time-dependent density matrix renormalization group (TDDMRG), correlating as many as 45 electrons in 50 orbitals. We believe that our results will be useful to design future experiments. The proposed IBO analysis is applicable to other types of real-time electron dynamics and spectroscopy.

2603.10104 2026-03-12 astro-ph.GA

A Kiloparsec-Scale Stellar Cavity in the Center of Abell402-BCG May be Caused by Dynamic Interactions with an Ultramassive Black Hole

Michael McDonald, Gourav Khullar, David Lagattuta, Guillaume Mahler, Shashank Dattathri, Jose M. Diego, Alastair C. Edge, Benjamin Floyd, Michael D. Gladders, Scott A. Hughes, Mathilde Jauzac, Nader Khonji, Gavin Leroy, Richard Massey, Mireia Montes, Priyamvada Natarajan, Michael Reefe, Keren Sharon, Frank van den Bosch, Stepane Werner, Adi Zitrin

Comments 11 pages, 6 figures, w/ more in appendix. Submitted to ApJL. Comments welcome!

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We present new observations from JWST NIRCam that reveal a striking kpc-wide cavity in the stellar distribution of the central galaxy in the cluster Abell402. Supporting data from HST allow us to rule out extinction due to dust as an explanation and, instead, suggest that this is a localized depression in the stellar density field corresponding to ~2x10^9 Msun in missing stars within a volume of 0.5kpc^3. On larger scales, both the JWST and HST data show evidence for a 2.2kpc flattened core in the stellar distribution (on which the smaller-scale cavity is superimposed), which implies the presence of a central ultra-massive black hole with M_BH = 6 +/- 4 x10^10 Msun. We report evidence for a mid-IR-bright point source at one edge of the cavity, suggesting that this black hole is actively accreting. MUSE spectroscopy reveal that this source is a LINER AGN and that there is a second candidate AGN on the opposite side of the cavity with a relative velocity of 370km/s -- if real, this implies the presence of a kpc-separation dual AGN with a total binary mass of 6 +/- 2 x10^10 Msun, which would make this the most massive binary black hole system discovered to date. We propose that this unique stellar cavity is the result of a short-lived dynamical interaction between at least one supermassive black hole and the background stellar density field, caused either by three-body scattering during binary hardening or the induction of a dipole instability in the stellar density field.

2603.10103 2026-03-12 cond-mat.str-el cond-mat.dis-nn cond-mat.mes-hall

Symmetric localization of $ν_{\text{tot}}=4/3$ fractional topological insulator edges

Yang-Zhi Chou, Sankar Das Sarma

Comments 7 pages, 1 figure

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Motivated by the recent twisted MoTe$_2$ experiment [arXiv:2601.18508], we develop a disordered interacting edge theory of a fractional topological insulator at $ν_{\text{tot}}=4/3$, consisting of two time-reversal-conjugated $ν=2/3$ fractional quantum Hall states. For an $S_z$-conserving edge, we uncover three distinct phases with two possible conductance values per edge in the long-edge limit: $\frac{2}{3}\frac{e^2}{h}$ and $\frac{4}{3}\frac{e^2}{h}$. In the presence of $S_z$-changing perturbations (e.g., Rashba spin-orbit coupling), an interaction-induced insulating edge state can emerge without breaking time-reversal or charge-conservation symmetry, corresponding to the absence of a topologically protected edge state. We further provide an exact mapping to a noninteracting fermionic theory exhibiting Anderson localization. Our results showcase an explicit, experimentally relevant example that the edge-state two-terminal transport is insufficient to identify the $ν_{\text{tot}}=4/3$ fractional topological insulators.

2603.10097 2026-03-12 gr-qc hep-th

Optical and orbital characterization of spherically symmetric static black holes of self-gravitating new nonlinear electrodynamics model

İlim İrfan Çimdiker, Ali Övgün, Yosef Verbin

Comments 28 pages, 14 figures

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Horizon scale imaging and precision lensing have turned black holes into quantitative laboratories for strong gravity and for non standard electromagnetic physics. We study the optical appearance and orbital dynamics of a new class of static spherically symmetric black holes sourced by a Palatini inspired nonlinear electrodynamics model, minimally coupled to Einstein-Hilbert gravity. Using a unified geodesic analysis, we identify the key radii that organize the strong field phenomenology. For photons we determine the unstable photon sphere, the associated critical capture threshold, and the resulting shadow size for a distant observer, and we map how these observables respond to the charge and to the nonlinearity index $n$. For massive probes we compute circular orbits and the innermost stable circular orbit, clarifying the departure from the Schwarzschild and Reissner-Nordström cases. We then connect to classical tests by evaluating the light deflection angle and periastron advance, providing additional diagnostics that complement the shadow. Our results furnish a practical reference model for confronting first order nonlinear electrodynamics black holes with current and forthcoming imaging and lensing data.

2603.10096 2026-03-12 math.GM

Adaptive Filtering via Canonical Systems with Time-Varying Hamiltonians

Keshav Raj Acharya, Pitambar Acharya

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In many practical applications, signals and environments are time- varying, which makes fixed filters unreliable. Adaptive filtering, on the other hand, updates in real time to suppress noise, track nonstationary signals, and identify unknown systems. This paper investigates an adaptive filtering frame- work based on canonical systems with time-varying symmetric positive semi- definite Hamiltonian matrices. The proposed method adapts the Hamiltonian matrix using a gradient-based scheme designed to minimize the squared er- ror between the system output and a desired reference signal. We establish theoretical stability guarantees via Lyapunov analysis, ensuring boundedness of system trajectories and convergence of the error signal under suitable as- sumptions. Furthermore, we present numerical integration schemes preserving the underlying Hamiltonian structure and projective techniques to maintain positive semidefiniteness of the Hamiltonian matrix. Extensive simulations on synthetic nonstationary signals illustrate the effectiveness and robustness of the proposed adaptive filter.

2603.10089 2026-03-12 stat.ME stat.AP

Trajectory-informed graph-based clustering for longitudinal cancer subtyping

Lara Cavinato, Marco Rocchi, Luca Viganò, Francesca Ieva

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Cancer subtyping plays a crucial role in informing prognosis and guiding personalized treatment strategies. However, conventional subtyping approaches often rely on static, biopsy-derived scores that hardly capture the biological heterogeneity and temporal evolution of the disease. In this study, we propose a novel trajectory-informed clustering method for cancer subtyping that integrates multi-modal clinical data and longitudinal patient trajectories. Our method constructs a patient similarity graph using time-varying imaging-derived features, clinical covariates, and transitions among key clinical states such as therapy, surveillance, relapse, and death. This graph structure enables the identification of patient subgroups that are not only phenotypically and genotypically distinct but also aligned with patterns of disease progression. We position our approach within the landscape of existing subtyping methods and highlight its advantages in terms of temporal modeling and graph-based interpretability. Through simulation studies and application to a real world dataset of liver metastases, we demonstrate the ability of our framework to uncover clinically relevant subtypes with distinct prognostic trajectories. Our results underscore the potential of trajectory-informed clustering to enhance personalized oncology by bridging cross-sectional biomarkers with dynamic disease evolution.

2603.10087 2026-03-12 cs.AR cs.DC

Pooling Engram Conditional Memory in Large Language Models using CXL

Ruiyang Ma, Teng Ma, Zhiyuan Su, Hantian Zha, Xinpeng Zhao, Xuchun Shang, Xingrui Yi, Zheng Liu, Zhu Cao, An Wu, Zhichong Dou, Ziqian Liu, Daikang Kuang, Guojie Luo

Comments Submitted to EuroMLSys'26

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Engram conditional memory has emerged as a promising component for LLMs by decoupling static knowledge lookup from dynamic computation. Since Engram exhibits sparse access patterns and supports prefetching, its massive embedding tables are well-suited for offloading to lower-tier memory. In this paper, we propose using Compute Express Link (CXL) memory pool for Engram storage. Compared to RDMA, CXL provides fine-grained and low-latency access required by minimal and discrete retrieval patterns of Engram. We integrate the CXL-based Engram pool into SGLang, achieving near-DRAM end-to-end performance. This provides a scalable and cost-efficient storage solution for future Engram-integrated LLMs without compromising inference performance.

2603.10086 2026-03-12 nlin.PS math.AP math.DS

How inertia affects autotoxicity-mediated vegetation dynamics: from close-to to far-from-equilibrium patterns

Giancarlo Consolo, Carmela Currò, Gabriele Grifò, Annalisa Iuorio, Giovanna Valenti, Frits Veerman

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In this work, the influence of inertial effects on the formation and evolution of vegetation patterns on sloped arid terrains is investigated from the onset of instability to far-from-equilibrium. Analyses are carried out in a hyperbolic extension of the one-dimensional Klausmeier model, where autotoxicity effects are also taken into account. As the system moves away from the wave bifurcation threshold, two classes of solutions arise: small-amplitude periodic migrating bands near onset and large-amplitude travelling pulses in far-from-equilibrium conditions. For the first class, results of LSA reveal that inertia has a twofold role at onset: it acts as a destabilising mechanism, thereby enlarging the parameter region in which uphill migrating vegetation bands can emerge, and it reduces the pattern migration speed. Its role also manifests itself close to onset, as proved by the Stuart-Landau equation for the pattern amplitude deduced via multiple-scale WNA. Indeed, it is shown that inertial effects may reverse the dynamical regime, from supercritical to subcritical, thus leading to hysteresis. For the second class of solutions, the travelling vegetation pulses are first captured via numerical simulations and then investigated via Geometric Singular Perturbation Theory (GSPT). In far-from-equilibrium conditions, inertia is shown to increase pulse speed while preserving the intrinsic multiscale structure of the solution, in full agreement with the numerical findings. Overall, the proposed combined analytical-numerical investigations have depicted several ecological scenarios as a function of the distance from the instability threshold, elucidating that inertia does not exclusively act as a time lag.

2603.10082 2026-03-12 gr-qc hep-th math-ph math.MP

Batalin-Fradkin-Vilkovisky quantization of Einstein gravity with off-diagonal solutions encoding Hořava type generating functions

Elşen Veli Veliev, Sergiu I. Vacaru

Comments latex2e, 11pt, 33 pages

Journal ref Eur. Phys. J. C 86 (2026) 80

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We develop and apply the Batalin-Fradkin-Vilkovisky (BFV) formalism for quantizing off-diagonal solutions of the Einstein equations in general relativity. In the quasi-classical limit of quantum gravity, such solutions possess specific nonlinear symmetries and encode Hořava - Lifshitz (HL) configurations with anisotropic scaling and effective cosmological constants. The geometric constructions are performed on Lorentz manifolds enabled with nonholonomic 2+2 and 3+1 fibration structures.

2603.10081 2026-03-12 cs.DB

Categorical Calculus and Algebra for Multi-Model Data

Jiaheng Lu

Comments In Proceedings ACT 2025, arXiv:2603.07595. arXiv admin note: substantial text overlap with arXiv:2504.09515

Journal ref EPTCS 442, 2026, pp. 75-90

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Multi-model databases are designed to store, manage, and query data in various models, such as relational, hierarchical, and graph data, simultaneously. In this paper, we provide a theoretical basis for querying categorical databases. We propose two formal query languages: categorical calculus and categorical algebra, by extending relational calculus and relational algebra respectively. We demonstrate the equivalence between these two languages of queries. We propose a series of transformation rules of categorical algebra to facilitate query optimization. Finally, we analyze the expressive power and computation complexity for the proposed query languages.

2603.10076 2026-03-12 astro-ph.EP astro-ph.IM

A test of the Dedalus software for exoplanet atmospheric dynamics

Rick Bonhof, Quentin Changeat, James Y-K. Cho

Comments 4 pages, Accepted in Research Notes of the AAS

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Studying exoplanet flow and variability requires solving atmospheric dynamics equations accurately. Here we use the shallow-water equations to evaluate and employ Dedalus3, a spectral method-based software package for solving differential equations. A well-known jet instability test is used for the evaluation; then, the package is used to investigate the nonlinear evolution of observed, Jupiter's zonal (east--west) jets; finally, the package is used to compare hot-Jupiter flows with different initial conditions. Our results indicate that Dedalus3 can be a useful tool for investigating planetary flow dynamics, but careful testing and execution are necessary for each problem.

2603.10073 2026-03-12 math.ST cs.IT math.IT math.PR stat.TH

Universal Shuffle Asymptotics, Part II: Non-Gaussian Limits for Shuffle Privacy -- Poisson, Skellam, and Compound-Poisson Regimes

Alex Shvets

Comments 35 pages. Part II of a series; Part I is arXiv:2602.09029

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Part I of this series (arXiv:2602.09029) develops a sharp Gaussian (LAN/GDP) limit theory for neighboring shuffle experiments when the local randomizer is fixed and has full support bounded away from zero. The present paper characterizes the first universality-breaking frontier: critical sequences of increasingly concentrated local randomizers for which classical Lindeberg conditions fail and the shuffle score exhibits rare macroscopic jumps. For shuffled binary randomized response with local privacy $\varepsilon_0 = \varepsilon_0(n)$, we prove experiment-level convergence (in Le Cam distance) to explicit shift limit experiments: a Poisson-shift limit for the canonical neighboring pair when $\exp(\varepsilon_0(n))/n \to c^2$, and a Skellam-shift limit for proportional compositions $k/n \to π\in (0,1)$ in the same scaling, including an explicit disappearance of the two-sided $δ$-floor away from boundary compositions. For general finite alphabets, we introduce a sparse-error critical regime and prove a multivariate compound-Poisson / independent Poisson vector limit for the centered released histogram, yielding a multivariate Poisson-shift experiment and an explicit limiting $(\varepsilon, δ)$ curve as a multivariate Poisson series. Together with Part I, these results yield a three-regime picture (Gaussian/GDP, critical Poisson/Skellam/compound-Poisson, and super-critical no privacy) under convergent macroscopic scalings.

2603.10070 2026-03-12 astro-ph.IM astro-ph.CO gr-qc

CHRONOS Science Program

Yuki Inoue, Mario Juvenal S Onglao, Vivek Kumar, Daiki Tanabe

Comments 202 pages

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Cryogenic sub-Hz cROss torsion-bar detector with quantum NOn-demolition Speed meter(CHRONOS) is a proposed next-generation ground-based gravitational-wave observatory designed to explore the sub-Hz frequency band with unprecedented sensitivity. Utilizing a cryogenic torsion-bar interferometric configuration with quantum non-demolition speed-meter readout, CHRONOS targets a frequency window that bridges space-based missions and current high-frequency ground-based detectors, opening a new frontier in gravitational-wave astronomy. The observatory will enable long-duration tracking of compact binary inspirals well before merger, significantly improving source localization, parameter estimation, and tests of general relativity. In addition to transient signals, CHRONOS is optimized to probe the stochastic gravitational-wave background (SGWB) in the sub-Hz regime, providing powerful constraints on primordial gravitational waves, inflationary tensor spectra with red or blue tilts, first-order phase transitions, cosmic strings, and other relics of high-energy physics. By connecting gravitational-wave measurements across cosmological frequency scales-from cosmic microwave background polarization to pulsar timing arrays and high-frequency interferometers-CHRONOS will contribute to a coherent reconstruction of the gravitational-wave spectrum over more than twenty orders of magnitude. Crossing critical sensitivity thresholds in the sub-Hz band, CHRONOS will establish a new pillar of gravitational-wave astronomy and cosmology, enabling transformative advances in astrophysics and fundamental physics.

2603.10066 2026-03-12 math.GT

A Gap in Stanfield's Proof of Sachs' Linear Linkless Embedding Conjecture

Ramin Naimi

Comments 4 pages, 4 figures

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英文摘要

This is a short note describing what I believe is a serious gap in Stanfield's proof of Sachs' conjecture that every linklessly embeddable graph has a linear linkless embedding in $\mathbb{R}^3$.

2603.10063 2026-03-12 cs.CR cs.SE

Building Privacy-and-Security-Focused Federated Learning Infrastructure for Global Multi-Centre Healthcare Research

Fan Zhang, Daniel Kreuter, Javier Fernandez-Marques, BloodCounts Consortium, Gregory Verghese, Bernard Butler, Nicholas Lane, Suthesh Sivapalaratnam, Joseph Taylor, Norbert C. J. de Wit, Nicholas S. Gleadall, Carola-Bibiane Schönlieb, Michael Roberts

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英文摘要

Collaborative healthcare research across multiple institutions increasingly requires diverse clinical datasets, but cross-border data sharing is strictly constrained by privacy regulations. Federated learning (FL) enables model training while keeping data local; however, many existing frameworks remain proof-of-concept and do not adequately address governance risks such as unauthorised participation, misuse, and lack of accountability. In particular, enforceable mechanisms for authentication, authorisation, and accounting (AAA) are often missing, limiting real-world clinical deployment. This paper presents FLA$^3$ (Federated Learning with Authentication, Authorisation, and Accounting), a governance-aware federated learning platform that operationalises regulatory obligations through runtime policy enforcement. FLA$^3$ integrates eXtensible Access Control Markup Language (XACML) compliant attribute-based access control (ABAC), cryptographic accounting, and study-scoped federation directly into the federated learning orchestration layer to enforce institutional sovereignty and protocol adherence. We evaluate FLA$^3$ through two complementary studies. First, we demonstrate operational feasibility by deploying the platform infrastructure across five BloodCounts! Consortium institutions in four countries: United Kingdom, Netherlands, India, and The Gambia. Second, we assess clinical utility using simulated federation of full blood count (FBC) data from 54,446 samples from 35,315 subjects across 25 centres in the INTERVAL study. Results show that FLA$^3$ achieves predictive performance comparable to centralised training while strictly enforcing governance constraints. These results show that enforceable governance can function as a first-class privacy-preserving control, improving trustworthiness for scalable artificial intelligence (AI) in cross-jurisdictional healthcare deployments.

2603.10058 2026-03-12 physics.med-ph physics.plasm-ph

Controlled kHz laser-driven electron irradiations for pre-clinical applications

C. M. Lazzarini, M. Favetta, E. R. Szabo, I. Zymak, L. V. N. Goncalves, M. Jech, S. Lorenz, M. Nevrkla, J. Sisma, A. Spadova, F. Vitha, R. Antipenkov, P. Bakule, A. Grenfell, V. Sobr, W. Szuba, J. Dudas, A. Ebert, R. Molnar, R. Polanek, S. V. Bulanov, K. Hideghety, G. M. Grittani

Comments 14 pages, 9 figures

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英文摘要

We report the first in-air irradiations of biological samples with kHz laser-driven electrons with beam energy 20 MeV, high-energy tail extending to 40 MeV, and average dose rate up to 30 Gy/min. An in-house procedure has been developed to characterize and deliver on-demand (i.e. pre-agreed date and time) the target electron beam energy, dose and dose uniformity. We present a tolerance analysis on the laser electron parameters, highlighting the importance of beam stability for precise irradiations of in vivo zebrafish embryos and in vitro U251 glioblastoma cell line. The observed improvement in the survival rate of the zebrafish embryos, combined with unchanged cytotoxicity in the cell cultures, indicates promising results for normal tissue sparing while maintaining anticancer efficacy. The pre-clinical results of this work represent an important milestone towards the clinical translation of laser-plasma accelerators.

2603.10056 2026-03-12 cs.CR cs.NI cs.SE

OAuthHub: Mitigating OAuth Data Overaccess through a Local Data Hub

Qiyu Li, Yuhe Tian, Haojian Jin

Comments Accepted to PETS 2026

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英文摘要

Most OAuth service providers, such as Google and Microsoft, offer only a limited range of coarse-grained data access. As a result, third-party OAuth applications often end up accessing more user data than necessary, even if their developers want to minimize data access. We present OAuthHub, a development framework that leverages users' personal devices as the intermediary controller for OAuth-based data sharing between cloud services. The key innovations of OAuthHub are: (1) the insight that discretionary data access is largely unnecessary for most OAuth apps, which typically only require access at three well-defined moments-during installation, in response to user actions, and at scheduled intervals; (2) a development framework that requires explicit declarations of intended data access and supports the three common access patterns through intermittently available personal devices; and (3) a centralized runtime permission model for managing OAuth access across providers. We evaluated OAuthHub with three real-world apps on both PCs and mobile phones and found that OAuthHub requires moderate changes to the application code and imposes insignificant performance overheads. Our study with 18 developers showed that participants completed programming tasks significantly faster (9.1 vs. 18.0 minutes) with less code (4.7 vs. 15.8 lines) using OAuthHub than conventional OAuth APIs.

2603.10050 2026-03-12 math.NA cs.NA

Geometrically Explicit Cosserat-Rod Modeling with Piecewise Linear Strain for Complex Rod Systems

Lingxiao Xun, Brahim Tamadazte

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英文摘要

This paper presents a geometrically explicit formulation for Cosserat rods that unifies configuration-space and strain-based representations within a single modeling framework. The proposed method uses nodal configurations on the Lie group SE(3) as generalized coordinates, while internal strains are reconstructed via a piecewise-linear parameterization. This hybrid design preserves the geometric rigor of Lie-group formulations and retains the locality, simplicity, and computational efficiency characteristic of strain-parameterized rod models. The formulation naturally avoids shear and membrane locking without additional stabilization techniques, and it accommodates arbitrary rod networks, closed-loop architectures, and gridshell-like structures through element-wise assembly. A Riemannian Newton solver is further developed to solve the equilibrium equations directly on SE(3), providing rapid convergence and consistent treatment of rotations. Numerical examples demonstrate that the method achieves high accuracy with only a few elements and generalizes seamlessly from single rods to complex multi-rod systems. These properties highlight the potential of the proposed formulation as a fast, robust, and scalable simulation tool for slender mechanisms and compliant structures.

2603.10045 2026-03-12 math.NA cs.NA physics.flu-dyn

A 3D sharp and conservative VOF method for modeling the contact line dynamics with hysteresis on complex boundaries

Chong-Sen Huang, Tian-Yang Han, Jie Zhang, Ming-Jiu Ni

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英文摘要

We propose a sharp and conservative 3D numerical method for simulating moving contact lines on complex geometries, developed within a coupled geometric Volume-of-Fluid (VOF) and embedded boundary framework. The first major contribution is a modified VOF advection and reconstruction scheme specifically designed for mixed cells containing liquid, gas, and solid phases. This formulation ensures strict local mass conservation in the presence of arbitrarily shaped embedded boundaries. To overcome the severe time-step limitation caused by small cut cells, a redistribution advection strategy is introduced, which completely removes the CFL constraint while preserving both local and global volume conservation. The second key contribution is a novel 3D contact angle imposition technique built upon the height function framework. By incorporating a pre-fitting paraboloid procedure, the method achieves robust curvature estimation and accurate enforcement of contact angle conditions on irregular solid surfaces. In addition, contact angle hysteresis is modeled to capture more realistic wetting dynamics. A series of challenging benchmark tests have been conducted to demonstrate the accuracy, robustness, and superiority of the proposed method compared with existing sharp-interface approaches. This study, for the first time, establishes a fully geometric and conservative VOF-based scheme capable of accurately resolving contact line dynamics on arbitrarily complex 3D surfaces.