New Neutron Star Equation of State with Quark-Hadron Crossover

Gordon Baym, Shun Furusawa, Tetsuo Hatsuda, Toru Kojo, Hajime Togashi

Research output: Contribution to journalArticlepeer-review

33 Citations (Scopus)

Abstract

We present a much improved equation of state for neutron star matter, QHC19, with a smooth crossover from the hadronic regime at lower densities to the quark regime at higher densities. We now use the Togashi et al. equation of state, a generalization of the Akmal-Pandharipande-Ravenhall equation of state of uniform nuclear matter, in the entire hadronic regime; the Togashi equation of state consistently describes nonuniform as well as uniform matter, and matter at beta equilibrium without the need for an interpolation between pure neutron and symmetric nuclear matter. We describe the quark matter regime at higher densities with the Nambu-Jona-Lasinio model, now identifying tight constraints on the phenomenological universal vector repulsion between quarks and the pairing interaction between quarks arising from the requirements of thermodynamic stability and causal propagation of sound. The resultant neutron star properties agree very well with the inferences of the LIGO/Virgo collaboration, from GW170817, of the pressure versus baryon density, neutron star radii, and tidal deformabilities. The maximum neutron star mass allowed by QHC19 is 2.35 M o, consistent with all neutron star mass determinations.

Original languageEnglish
Article number42
JournalAstrophysical Journal
Volume885
Issue number1
DOIs
Publication statusPublished - 2019 Nov 1
Externally publishedYes

Keywords

  • dense matter
  • elementary particles
  • equation of state
  • stars: neutron

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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