Effect of the Coulomb interaction on the liquid-gas phase transition of nuclear matter

TL;DR

This study explores how Coulomb interactions influence the liquid-gas phase transition in nuclear matter with different proton fractions, revealing a reduction in transition temperature but little change in critical density.

Contribution

It provides a detailed analysis of Coulomb effects on phase transition parameters across various proton fractions using quantum molecular dynamics simulations.

Findings

Coulomb interaction lowers transition temperature by 1-2 MeV.

Critical density remains largely unaffected by Coulomb effects.

Transition temperature varies with proton fraction.

Abstract

We investigate the role of the Coulomb interaction on the liquid-gas phase transition of nuclear matter with three different values of proton fraction ($Y_p$=0.5,0.3 and 0.1), relevant for heavy-ion physics as well as various astrophysical scenarios, within the framework of quantum molecular dynamics. We perform simulations for a wide range of density and temperature with and without the Coulomb interaction and calculate the two-point correlation functions of nucleon density fluctuations for all the configurations to determine the phase transition region. We also determine the critical end point of the liquid-gas phase transition for all three values of proton fraction considered. We observe that the Coulomb interaction reduces the transition temperature by about 2 MeV for nuclear matter with $Y_p$=0.5 and 0.3 and by about 1 MeV for nuclear matter with $Y_p$=0.1. However, the critical density is found to be more or less insensitive to the Coulomb interaction.