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Nuclear Theory·nucl-th

Thursday·July 3, 2025

14 papers—7 primary·7 cross-listed

All14Primary7Cross-lists7
  1. 08

    [Submitted on 1 Jul 2025] (cross-list from quant-ph)

    Quantum Simulation of QED in Coulomb Gauge

    Xiaojun Yao🇺🇸

    A recent work considered quantum simulation of Quantum Electrodynamics on a lattice in the Coulomb gauge with gauge degrees of freedom represented in the occupation basis in momentum space. Here we consider the more efficient representation of the gauge degrees of freedom in field basis in position space and develop a quantum algorithm for real-time simulation. We show that the continuum Coulomb gauge Hamiltonian is equivalent to the temporal gauge Hamiltonian when acting on physical states consisting of fermion and transverse gauge fields. The Coulomb gauge Hamiltonian is discretized by using the Green's function of the discrete Laplacian operator under the Dirichlet boundary conditions. Both the continuum Coulomb gauge Hamiltonian and the discretized one proposed here guarantee that the unphysical longitudinal gauge fields are decoupled and commute with the corresponding Hamiltonian. Thus there is no need to impose any constraint. The local gauge field basis and the canonically conjugate variable basis are swapped efficiently using the quantum Fourier transform. We prove that the qubit cost to represent physical states and the gate count for real-time simulation scale polynomially with the lattice size, energy, time, accuracy, and Hamiltonian parameters in lattice units. The gate cost here for implementing the time evolution of the gauge field is reduced at least by a factor on the order of for modest lattice size and accuracy level compared with the previous work.

    Comments:
    32 pages; v2: published version, added a comparison of gate costs with previous work
    Subjects:
    Quantum Physics (quant-ph); High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2507.01089 [pdf]
    PRD(2026)·10 citations
  2. 09

    [Submitted on 1 Jul 2025] (cross-list from astro-ph.HE)

    Effect of symmetry energy on properties of rapidly rotating neutron stars and universal relations

    Pion Sudarshan Yeasin🇵🇱 · Stefanos Tsiopelas🇵🇱 · Armen Sedrakian🇵🇱 · Jia-Jie Li🇨🇳

    We investigated universal relations for compact stars rotating at the Keplerian (mass-shedding) limit, which is highly relevant for understanding the rapidly rotating objects formed in the aftermath of a neutron star-neutron star merger. Our analysis is based on a set of nucleonic equations of state (EoSs) featuring systematic variations in the symmetry energy slope parameter and the isoscalar skewness parameter , varied within ranges that are broadly consistent with current laboratory and astrophysical constraints. The global observable properties of isolated maximally rotating stars are examined, focusing on the mass-radius relation, moment of inertia, quadrupole moment, and the Keplerian (maximum) rotation frequency, as well as their variations in the - parameter space. Next, we demonstrate that, in the limit of Keplerian rotation, universal relations remain valid across the same set of EoSs characterized by varying and . In particular, we present explicit results for the moment of inertia () and quadrupole moment () as functions of compactness, as well as for the moment of inertia-quadrupole moment relation. All of these relations exhibit excellent universality, with deviations typically within a range from a few percent to 10\% across a wide range of parameters. Additionally, we verify for our set of EoSs that the universality of - holds to higher accuracy (at the level of 1\%) in the slow-rotation approximation compared with the Kepler limit, where the relative error increases up to . Our findings support the applicability of -Love--type universal relations in observational modeling of maximally rotating compact stars and the gravitational wave emitted by them.

    Comments:
    v2: 12 pages, 9 figures, journal version. v1: 11 pages, 8 figures
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th)
    arXiv:
    2507.01093 [pdf]
    PRD(2025)·2 citations
  3. 10

    [Submitted on 2 Jul 2025] (cross-list from astro-ph.HE)

    Self-bound hybrid stars with strong phase transitions can relieve major compact star observation tensions

    Chen Zhang🇨🇳 · Juan M. Z. Pretel🇧🇷 · Renxin Xu🇨🇳

    Some recent pulsar observations cannot naturally fit into the conventional picture of neutron stars: the compact objects associated with HESS J1731-347 and XTE J1814-338 have too small radii in the low-mass regime, while the secondary component of GW190814 is too massive for neutron stars to be compatible with constraints from the GW170817 event. In this study, we demonstrate that all these anomalous observations and tensions, together with other conventional ones such as recent NICER observations of PSR J0740+6620, J0030+0451, and PSR J0437-4715, can be naturally explained simultaneously by a new general type of self-bound hybrid stars with large density discontinuities, and thus are radially stable in either the slow or rapid phase transition context. As a proof of concept, we use hybrid quark stars, inverted hybrid stars, and hybrid strangeon stars as benchmark examples to explicitly demonstrate the advantage and feasibility of self-bound hybrid stars with strong phase transitions in relieving all tensions related to compact stars' masses, radii, and tidal deformabilities.

    Comments:
    15 pages, 5 figures; PRD accepted version
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2507.01371 [pdf]
    PRD(2026)·13 citations
  4. 11

    [Submitted on 2 Jul 2025] (cross-list from nucl-ex)

    Nuclear Physics Confronts Relativistic Collisions Of Isobars

    Giuliano Giacalone🇩🇪 · Jiangyong Jia🇺🇸 · Vittorio Somà🇫🇷 · You Zhou🇩🇰 · Anatoli Afanasjev🇺🇸 · Massimiliano Alvioli🇮🇹 · Benjamin Bally🇫🇷 · Federica Capellino🇩🇪 · Jean-Paul Ebran🇫🇷 · Hannah Elfner🇩🇪 · Fernando G. Gardim🇧🇷 · André V. Giannini🇧🇷 and 34 other authors

    High-energy collisions involving the isobars Zr and Ru have been performed in 2018 at Brookhaven National Laboratory's Relativistic Heavy Ion Collider (RHIC) as a means to search for the chiral magnetic effect in QCD. This would manifest itself as specific deviations from unity in the ratio of observables taken between Zr+Zr and Ru+Ru collisions. Measurements of such ratios (released at the end of 2021) indeed reveal deviations from unity, but these are primarily caused by the two collided isobars having different radial profiles and intrinsic deformations. To make progress in understanding RHIC data, nuclear physicists across the energy spectrum gathered in Heidelberg in 2022 as part of an EMMI Rapid Reaction Task Force (RRTF) to address the following question. Does the combined effort of low-energy nuclear structure physics and high-energy heavy-ion physics enable us to understand the observations made in isobar collisions at RHIC?

    Comments:
    112 pages, 39figs; Report of the EMMI RRTF "Nuclear Physics Confronts Relativistic Collisions of Isobars" https://indico.gsi.de/event/14430/ https://indico.gsi.de/event/15627/
    Subjects:
    Nuclear Experiment (nucl-ex); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2507.01454 [pdf]
    26 citations
  5. 12

    [Submitted on 2 Jul 2025] (cross-list from hep-ph)

    Pentaquarks made of light quarks and their admixture to baryons

    Nicholas Miesch🇺🇸 · Edward Shuryak🇺🇸 · Ismail Zahed🇺🇸

    This paper is a continuation of our studies of multiquark hadrons. The anti-symmetrization of their wavefunctions required by Fermi statistics is nontivial, as it mixes orbital, color, spin and flavor structures. In our previous papers we developed a method to find them based on the representations of the permutation group, and derived the explicit wave functions for baryons excited to the first and second shells , tetraquarks and hexaquarks (). Now we apply it to light pentaquarks (), in the S- and P-shells (). Using Jacobi coordinates, one can use the hyperdistance approximation in 12-dimensional space. We further address the issue of ``unquenching" of baryons, by considering their mixing with pentaquarks, via two channels, through the addition of -like or -like pairs. This mixing is central for understanding of the observed flavor asymmetry of the antiquark sea, the amount of orbital motion issue as well as other nucleon properties.

    Comments:
    In version 2 one missing reference is added
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2507.01861 [pdf]
    PRD(2025)·2 citations
  6. 13

    [Submitted on 2 Jul 2025] (cross-list from hep-ph)

    Spin hydrodynamics -- recent developments

    Samapan Bhadury🇵🇱 · Zbigniew Drogosz🇵🇱 · Wojciech Florkowski🇵🇱 · Valeriya Mykhaylova🇵🇱

    After briefly touching on relativistic hydrodynamics, we provide a detailed description of recent developments in spin hydrodynamics. We discuss the theory of perfect spin hydrodynamics within two different approaches, which lead to identical generalized thermodynamic relations. We also indicate the applicability range of the theory, finding it compatible with the conditions existing in the late stages of heavy-ion collisions. Finally, we discuss the near-equilibrium dynamics.

    Comments:
    8 pages, Proceedings of 8th International Conference on Physics and Astrophysics of Quark Gluon Plasma (ICPAQGP-2023). arXiv admin note: text overlap with arXiv:2411.19673
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2507.01864 [pdf]
    J.Subatomic Part.Cosmol.(2025)·4 citations
  7. 14

    [Submitted on 2 Jul 2025] (cross-list from hep-ex)

    The Roper Resonance in Nucleon-Nucleon Collisions and the Issue of Dibaryons

    Heinz Clement🇩🇪

    In many reactions leading to excitations of the nucleon the Roper resonance can be sensed only by complex partial-wave analyses. In nucleon-nucleon collisions the isoscalar single-pion production as well as specific two-pion production channels present the Roper excitation free of competing resonance processes at a mass of 1370 MeV and a width of 150 MeV. A detailed analysis points to the formation of dibaryonic systems during the nucleon-nucleon collision process similar to what is known from the threshold.

    Subjects:
    High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2507.01937 [pdf]
    Acta Phys.Polon.B(2026)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE