Cold quarks in medium: an equation of state

TL;DR

This paper derives a semi-analytical equation of state for cold quark matter within a covariant model, capturing deconfinement and chiral symmetry restoration, and highlighting the impact of confinement on thermodynamics.

Contribution

It provides a compact algebraic form of the quark matter EoS and detailed expressions for density distributions and vacuum pressure differences in different phases.

Findings

Confinement significantly alters distribution functions.

The derived EoS captures phase transitions in cold quark matter.

Vacuum-pressure difference defines the bag constant.

Abstract

We derive a compact, semi-algebraic expression for the cold quark matter equation of state (EoS) in a covariant model that exhibits coincident deconfinement and chiral symmetry restoring transitions in-medium. Along the way we obtain algebraic expressions for: the number- and scalar-density distributions in both the confining Nambu and deconfined Wigner phases; and the vacuum-pressure difference between these phases, which defines a bag constant. The confining interaction materially alters the distribution functions from those of a Fermi gas and consequently has a significant impact on the model's thermodynamic properties, which is apparent in the EoS.