Generalized density functional equation of state for astrophysical simulations with 3-body forces and quark gluon plasma

TL;DR

This paper introduces a comprehensive nuclear equation of state for astrophysical simulations, incorporating 3-body forces, mesonic states, and phase transitions to QCD matter, improving modeling of supernovae and neutron stars.

Contribution

It develops a generalized DFT-based EoS including high-density effects, pions, and phase transitions, with first simulation results demonstrating its astrophysical relevance.

Findings

The EoS satisfies neutron star maximum mass constraints.

Inclusion of pions softens the core during supernova collapse.

Phase transition to QCD matter affects core dynamics.

Abstract

We present an updated general purpose nuclear equation of state (EoS) for use in simulations of core-collapse supernovae, neutron star mergers and black hole collapse. This EoS is formulated in the context of Density Functional Theory (DFT) and is generalized to include all DFT EoSs consistent with known nuclear and astrophysical constraints. This EoS also allows for the possibility of the formation of material with a net proton excess ($Y_p > 0.5$) and has an improved treatment of the nuclear statistical equilibrium and the transition to heavy nuclei as the density approaches nuclear matter density. We include the effects of pions in the regime above nuclear matter density and incorporate all of the known mesonic and baryonic states at high temperature. We analyze how a 3-body nuclear force term in the DFT at high densities stiffens the EoS to satisfy the maximum neutron star constraint, however the density dependence of the symmetry anergy and the formation of pions at high temperatures allows for a softening of the central core in supernova collapse calculations leading to a robust explosion. We also add the possibility of a transition to a QCD chiral-symmetry-restoration and deconfinement phase at densities above nuclear matter density. This paper details the physics, and constraints on, this new EoS and presents an illustration of its implementation in both neutron stars and core-collapse supernova simulations. We present the first results from core-collapse supernova simulations with this EoS.