High density matter

TL;DR

This review surveys recent theoretical developments in modeling the equation of state for high-density matter, incorporating complex compositions like strange baryons and quark matter, and compares models with astrophysical observations.

Contribution

It provides a comprehensive comparison of various EoS models for high-density matter, including their consistency with neutron star data and heavy-ion collision results.

Findings

Model EoS can explain neutron star masses and radii

Composition of neutron stars varies with rotation and temperature

Compatibility between astrophysical and laboratory data is discussed

Abstract

The microscopic composition and properties of matter at super-saturation densities have been the subject of intense investigation for decades. The scarcity of experimental and observational data has lead to the necessary reliance on theoretical models. However, there remains great uncertainty in these models, which, of necessity, have to go beyond the over-simple assumption that high density matter consists only of nucleons and leptons. Heavy strange baryons, mesons and quark matter in different forms and phases have to be included to fulfil basic requirements of fundamental laws of physics. In this review the latest developments in construction of the Equation of State (EoS) of high-density matter at zero and finite temperature assuming different composition of the matter are surveyed. Critical comparison of model EoS with available observational data on neutron stars, including gravitational masses, radii and cooling patterns is presented. The effect of changing rotational frequency on the composition of neutron stars during their lifetime is demonstrated. Compatibility of EoS of high-density, low temperature compact objects and low density, high temperature matter created in heavy-ion collisions is discussed.