Equation of State of Dense Matter from a density dependent relativistic mean field model

TL;DR

This paper develops a comprehensive equation of state for dense nuclear matter using a density-dependent relativistic mean field model, covering a wide range of conditions relevant for astrophysics.

Contribution

It introduces a modified RMF model with density-dependent couplings and provides an extensive EoS table for various temperatures, densities, and proton fractions, useful for astrophysical simulations.

Findings

Generated a detailed EoS table with over 107,000 grid points.

Covered a broad range of temperatures and densities relevant for neutron stars.

Implemented self-consistent calculations of nonuniform nuclear matter.

Abstract

We calculate the equation of state (EoS) of dense matter, using a relativistic mean field (RMF) model with a density dependent coupling that is a slightly modified form of the original NL3 interaction. For nonuniform nuclear matter we approximate the unit lattice as a spherical Wigner-Seitz cell, wherein the meson mean fields and nucleon Dirac wave functions are solved fully self-consistently. We also calculate uniform nuclear matter for a wide range of temperatures, densities, and proton fractions, and match them to non-uniform matter as the density decreases. The calculations took over 6,000 CPU days in Indiana University's supercomputer clusters. We tabulate the resulting EoS at over 107,000 grid points in the proton fraction range $Y_P$ = 0 to 0.56. For the temperature range $T$ = 0.16 to 15.8 MeV we cover the density range $n_B$ = 10$^{-4}$ to 1.6 fm$^{-3}$; and for the higher temperature range $T$ = 15.8 to 80 MeV we cover the larger density range $n_B$ = 10$^{-8}$ to 1.6 fm$^{-3}$. In the future we plan to study low density, low temperature (T$<$15.8 MeV), nuclear matter using a Virial expansion, and we will match the low density and high density results to generate a complete EoS table for use in astrophysical simulations of supernova and neutron star mergers.