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Nuclear Theory·nucl-th

Thursday·June 19, 2025

11 papers—5 primary·6 cross-listed

All11Primary5Cross-lists6
  1. 06

    [Submitted on 17 Jun 2025] (cross-list from astro-ph.HE)

    A NICER view of the 1.4 solar-mass edge-on pulsar PSR J0614-3329

    Lucien Mauviard🇫🇷 · Sebastien Guillot🇫🇷 · Tuomo Salmi🇫🇮 · Devarshi Choudhury🇳🇱 · Bas Dorsman🇳🇱 · Denis González-Caniulef🇫🇷 · Mariska Hoogkamer🇳🇱 · Daniela Huppenkothen🇳🇱 · Christine Kazantsev🇫🇷 · Yves Kini🇳🇱 · Jean-Francois Olive🇫🇷 · Pierre Stammler🇫🇷 and 11 other authors

    Four neutron star radius measurements have already been obtained by modeling the X-ray pulses of rotation-powered millisecond pulsars observed by the Neutron Star Interior Composition ExploreR (NICER). We report here the radius measurement of PSR J0614-3329 employing the same method with NICER and XMM-Newton data using Bayesian Inference. For all different models tested, including one with unrestricted inclination prior, we retrieve very similar non-antipodal hot regions geometries and radii. For the preferred model, we infer an equatorial radius of km for a mass of (median values with equal-tailed credible interval), the latter being essentially constrained from radio timing priors obtained by MeerKAT. A more complex model, fitting the data equally well, resulted in a consistent inferred radius. We find that, for all different models, the pulse emission originates from two hot regions, one at the pole and the other at the equator. The resulting radius constraint is consistent with previous X-ray and gravitational wave measurements of neutron stars in the same mass range. Equation of state inferences, including previous NICER and gravitational wave results, slightly soften the equation of state with PSR J06143329 included and shift the allowed mass-radius region toward lower radii by m, which is compatible with previous analyses to within less than one standard deviation.

    Comments:
    25 pages, 12 figures and 4 tables. Accepted for publication in ApJ. Data files available in Zenodo
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Theory (nucl-th)
    arXiv:
    2506.14883 [pdf]
    ApJ(2025)·130 citations
  2. 07

    [Submitted on 17 Jun 2025] (cross-list from hep-ph)

    Review of heat and charge transport in strongly magnetized relativistic plasmas

    Igor A. Shovkovy🇺🇸 · Ritesh Ghosh🇺🇸

    We review field-theoretic studies of charge transport in hot relativistic plasmas under strong magnetic fields and extend the analysis to thermal conductivity. The calculations rely on accurately determining the fermion damping rate. Using the Landau-level representation, these damping rates are computed exactly at leading order and incorporated into the Kubo formula to obtain the thermal and electrical conductivity tensors. Our analysis reveals that the mechanisms underlying longitudinal and transverse transport differ significantly. Strong magnetic fields markedly suppress transverse charge transport by confining particles within localized Landau orbits, allowing transport only through quantum transitions between these discrete states. In contrast, longitudinal charge transport is enhanced, as it primarily depends on the reduced scattering probability of particles moving along the direction of the magnetic field. The anisotropy of thermal conductivity is also nontrivial but less pronounced since its underlying transport mechanism is different. We also examine the modification of the Wiedemann--Franz law in strongly magnetized plasmas.

    Comments:
    21 pages, 4 multipanel figures; corrected and improved
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2506.14956 [pdf]
    AAPPS Bull.(2025)·6 citations
  3. 08

    [Submitted on 17 Jun 2025] (cross-list from hep-ph)

    Thermalization from quantum entanglement: jet simulations in the massive Schwinger model

    Adrien Florio🇩🇪 · David Frenklakh🇺🇸 · Sebastian Grieninger🇺🇸 · Dmitri E. Kharzeev🇺🇸 · Andrea Palermo🇺🇸 · Shuzhe Shi🇨🇳

    We investigate the emergence of thermalization in a quantum field-theoretic model mimicking the production of jets in QCD -- the massive Schwinger model coupled to external sources. Specifically, we compute the expectation values of local operators as functions of time and compare them to their thermal counterparts, quantify the overlap between the evolving density matrix and the thermal one, and compare the dynamics of the energy-momentum tensor to predictions from relativistic hydrodynamics. Through these studies, we find that the system approaches thermalization at late times and elucidate the mechanisms by which quantum entanglement drives thermalization in closed field-theoretic systems. Our results show how thermodynamic behavior emerges in real time from unitary quantum dynamics.

    Comments:
    20 pages, 21 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
    arXiv:
    2506.14983 [pdf]
    PRD(2025)·27 citations
  4. 09

    [Submitted on 18 Jun 2025] (cross-list from hep-ph)

    Ambiguities in the Partial-Wave Analysis of the Photoproduction of Pairs of Pseudoscalar Mesons

    J. Guo🇺🇸 · E. Barriga🇺🇸 · K. Scheuer🇺🇸 · A. Austregesilo🇺🇸 · P. Eugenio🇺🇸 · D. I. Glazier🇬🇧 · B. Grube🇺🇸 · W. Imoehl🇺🇸 · C. A. Meyer🇺🇸 · A. Ostrovidov🇺🇸 · J. R. Stevens🇺🇸

    Applying the technique of partial-wave analysis, there are cases where more than one set of underlying complex-valued amplitudes can describe the measured observables. These ambiguities can sometimes be resolved using additional information, but assumptions are often required. It is known that the partial-wave analysis of two-pseudoscalar meson systems produced in photoproduction with a linearly polarized photon beam is free from discrete ambiguities stemming from the Barrelet zeros when the nucleon spin is ignored. In this article, we show that continuous ambiguities are possible for certain wave sets, even though the discrete ambiguities do not appear. We also explore ways to resolve these ambiguities and determine the maximal amount of information that can be obtained from analyses that suffer from these continuous ambiguities.

    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2506.15128 [pdf]
    PRD(2025)·1 citation
  5. 10

    [Submitted on 18 Jun 2025] (cross-list from hep-ph)

    Effects of a Brueckner-Hartree-Fock-corrected effective mass on speed of sound, conformality, and observables of dark matter-admixed neutron stars

    Arijit Das🇮🇳 · Prashanth Jaikumar🇺🇸 · Adarsh Karekkat🇮🇳 · Tanumoy Mandal🇮🇳

    We construct an equation of state describing cold and dense matter in the core of neutron stars which includes an admixture of fermionic dark matter and incorporates nucleon effective masses derived from the relativistic Brueckner-Hartree-Fock (BHF) many-body approach within a relativistic mean-field model. Such a BHF-informed mixed-model approach increases stellar compactness, with mass-radius configurations which are consistent with smaller, lighter pulsars. The model displays the expected non-monotonic behavior of sound speed hinted at by neutron star data, and is closer to the conformal bound at maximum mass. We find that the model displays tension with bounds on heavier pulsars, suggesting that the hypothesis of an aggregated dark component in neutron stars needs further critical study.

    Comments:
    18 pages, 5 figures and 5 tables, matches with the journal version
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
    arXiv:
    2506.15328 [pdf]
    PRC(2025)·2 citations
  6. 11

    [Submitted on 18 Jun 2025] (cross-list from hep-th)

    Relaxation for massive particles: transport and causality

    Matej Bajec🇸🇮 · Alexander Soloviev🇸🇮

    Correlators at finite density and temperature encode important information about a physical system, such as transport and causality. For a massive gas of particles in the relaxation time approximation of kinetic theory, we provide complete analytic results for all first order transport coefficients, including thermoelectric coefficients. We demonstrate the first complete picture of the complex structure of the correlators as a function of mass, providing an interpretation in terms of the causal structure of lightcones. We provide a simple criterion to extract the effective lightcone velocity from the cut of the retarded correlator.

    Comments:
    26 pages, 14 figures, v2: Added references and typos fixed, version accepted for publication
    Subjects:
    High Energy Physics — Theory (hep-th); Quantum Gases (cond-mat.quant-gas); Nuclear Theory (nucl-th)
    arXiv:
    2506.15531 [pdf]
    PRD(2025)·11 citations

Affiliations

first authorsco-authorsvia INSPIRE