Nuclear statistical equilibrium equation of state with a parametrized Dirac-Brückner Hartree-Fock calculation

Shun Furusawa, Hajime Togashi, Kohsuke Sumiyoshi, Koichi Saito, Shoichi Yamada, Hideyuki Suzuki

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

We calculate new equations of state (EOSs) for astrophysical simulations in the framework of the extended nuclear statistical equilibrium, in which we minimize the free energy density for the full ensemble of nuclei in a hot and dense stellar environment. To evaluate bulk and surface energies of heavy nuclei and free energies of uniformly distributed nucleons, we use fitting formulae for the interaction energies and single-nucleon potentials at zero temperature of a Dirac-Brückner Hartree-Fock (DBHF) theory, one of the modern approaches to describe homogeneous nuclear matter. We find that the DBHF EOS exhibits larger mass fractions for medium-mass nuclei and smaller mass fractions for the other nuclei than the EOS obtained using the variational method (VM), another modern model for homogeneous nuclear matter. This effect is due to the more deeply bound energy for symmetric nuclear matter and the larger symmetry energy encoded in the DBHF EOS. At supra-nuclear densities, the DBHF EOS exhibits characteristics of a larger free energy, a higher pressure, and a larger neutron chemical potential of neutron-rich matter, which lead to a larger radius of cold neutron stars than that obtained by the VM EOS.

Original languageEnglish
Article number013D05
JournalProgress of Theoretical and Experimental Physics
Volume2020
Issue number1
DOIs
Publication statusPublished - 2020 Jan 1

Keywords

  • D41
  • D42
  • E26

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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