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Nuclear Theory·nucl-th

Wednesday·April 14, 2021

12 papers—6 primary·6 cross-listed

All12Primary6Cross-lists6
  1. 01

    [Submitted on 13 Apr 2021]

    Properties of a quantum vortex in neutron matter

    Daniel Pęcak🇵🇱 · Nicolas Chamel🇧🇪 · Piotr Magierski🇵🇱 · Gabriel Wlazłowski🇵🇱

    We have studied systematically microscopic properties of a quantum vortex in neutron matter at finite temperatures and densities corresponding to different layers of the inner crust of a neutron star. To this end and in preparation of future simulations of the vortex dynamics, we have carried out fully self-consistent 3D Hartree-Fock-Bogoliubov calculations, using one of the latest nuclear energy-density functionals from the Brussels-Montreal family, which has been developed specifically for applications to neutron superfluidity in neutron-star crusts. By analyzing the flow around the vortex, we have determined the effective radius relevant for the vortex filament model. We have also calculated the specific heat in the presence of the quantum vortex and have shown that it is substantially larger than for a uniform system at low temperatures. The low temperature limit of the specific heat has been identified as being determined by Andreev states inside the vortex core. We have shown that the specific heat in this limit does not scale linearly with temperature. The typical energy scale associated with Andreev states is defined by the minigap, which we have extracted for various neutron-matter densities. Our results suggest that vortices may be spin-polarized in the crust of magnetars. Finally, we have obtained a lower bound for the specific heat of a collection of vortices with given surface density, taking into account both the contributions from the vortex core states and from the hydrodynamic flow.

    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
    arXiv:
    2104.05880 [pdf]
    PRC(2021)·15 citations
  2. 02

    [Submitted on 13 Apr 2021]

    Non-extensive Boltzmann Transport Equation: the Relaxation Time Approximation and Beyond

    Trambak Bhattacharyya🇷🇺

    We derive approximate iterative analytical solutions of the non-extensive Boltzmann transport equation in the relaxation time approximation. The approximate solutions almost overlap with the exact solution for a considerably wide range of the parameter values found in describing particle spectra originated in high-energy collisions. We also discuss the Landau kinetic approximation of the non-extensive Boltzmann transport equation and the emergence of the non-extensive Fokker-Planck equation, and use it to estimate the drag and diffusion coefficients of highly energetic light quarks passing through a gluonic plasma.

    Comments:
    10 pages, 10 figures, in press
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2104.05949 [pdf]
    Physica A(2023)·8 citations
  3. 03

    [Submitted on 13 Apr 2021]

    Heavy Magnetic Neutron Stars

    I. A. Rather🇮🇳 · Usuf Rahaman🇮🇳 · V. Dexheimer🇺🇸 · A. A. Usmani🇮🇳 · S. K. Patra🇮🇳

    We systematically study the properties of pure nucleonic and hyperonic magnetic stars using a density-dependent relativistic mean field (DD-RMF) equations of state. We explore several parameter sets and hyperon coupling schemes within the DD-RMF formalism. We focus on sets that are in better agreement with nuclear and other astrophysical data, while generating heavy neutron stars. Magnetic field effects are included in the matter equation of state and in general relativity solutions, which in addition fulfill Maxwell's equations. We find that pure nucleonic matter, even without magnetic field effects, generates neutron stars that satisfy the potential GW190814 mass constraint; however, this is not the case for hyperonic matter, which instead only satisfies the more conservative 2.1 M constraint. In the presence of strong but still somehow realistic internal magnetic fields G, the stellar charged particle population re-leptonizes and de-hyperonizes. As a consequence, magnetic fields stiffen hyperonic equations of state and generate more massive neutron stars, which can satisfy the possible GW190814 mass constraint but present a large deformation with respect to spherical symmetry.

    Comments:
    13 pages, 15 figures, 6 tables: Accepted for Publication in ApJ
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
    arXiv:
    2104.05950 [pdf]
    ApJ(2021)·35 citations
  4. 04

    [Submitted on 13 Apr 2021]

    Spin-triplet proton-neutron pair in spin-dipole excitations

    Kenichi Yoshida · Yusuke Tanimura

    Background: Spin-triplet () proton-neutron (pn) pairing in nuclei has been under debate. It is well known that the dynamical pairing affects the nuclear matrix element of the Gamow-Teller (GT) transition and the double beta decay. Purpose: We investigate the effect of the pn-pair interaction in the channel on the low-lying spin-dipole (SD) transition. We then aim at clarifying the distinction of the role in between the SD and GT transitions. Method: We perform a three-body model calculation for the transition , where is taken as a core. The strength of the pair interaction is varied to see the effect on the SD transition-strength distribution. To fortify the finding obtained by the three-body model, we employ the nuclear energy-density functional method for the SD transitions in several nuclei, where one can expect a strong effect. Results: The effect of the pn-pair interaction depends on the spatial overlap of the pn pair and the angular momentum of the valence nucleons; the higher the angular momentum of the orbitals, the more significant the effect. Conclusions: The dynamical pairing is effective even for SD states although the spatial overlap of the pn pair can be smaller than GT states. The SD transition involving high- orbitals with the same principal quantum number is strongly affected by the dynamical pairing.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2104.06049 [pdf]
    PRC(2021)·2 citations
  5. 05

    [Submitted on 4 Mar 2021]

    Thermonuclear fusion and generalized Gamow penetrability factor in intense laser fields

    Jintao Qi🇨🇳

    A theoretical study on thermonuclear fusion including deuterium-tritium (D-T) fusion and D-He fusion in intense laser fields has been shown in this article. With the laser fields expected to be available in the near future, some quantitative results for the laser-induced modifications to the cross-sections are given. It is reported that the cross-sections are more sensitive to the external laser fields at the lower energies. An explicit generalized form of the Gamow penetrability factor is given for the predictions of the laser-induced effects for some other similar nuclear processes.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2104.06190 [pdf]
    NPA(2022)·5 citations
  6. 06

    [Submitted on 13 Apr 2021]

    The Neutron-Rich Edge of the Nuclear Landscape. Experiment and Theory

    Frédéric Nowacki🇫🇷 · Alexandre Obertelli🇩🇪 · Alfredo Poves🇪🇸

    In this review, we describe the experimental facilities and methods which make it possible to produce and measure the properties of the extreme neutron rich nuclei. We then develop the theoretical framework that will accompany us along the review; the shell-model approach with large scale configuration interaction (mixing) SM-CI, with special emphasis in the competition between the spherical mean field and the nuclear correlations (mainly pairing and quadrupole-quadrupole). The symmetry properties of the latter are treated in detail as they will show to be of great heuristic value. We explore in detail the Islands of Inversion (IoI) at N=20 and N=28. We make a side excursion into the heavier Calcium and Potassium isotopes, to discuss current issues on shell evolution and new magic numbers far from stability. We visit the N=40 Island of Inversion. We discuss the doubly magic nucleus 78Ni, its shape coexistence and the prospect of a new IoI at N=50 below Z=28. We examine the N=70 and N=82 neutron closures approaching the neutron drip line.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2104.06238 [pdf]
    PPNP(2021)·96 citations

Affiliations

first authorsco-authorsvia INSPIRE