Equation of state in the PNJL model with the entanglement interaction

TL;DR

This paper enhances the PNJL model with an entanglement interaction to better match lattice QCD data, explores the phase diagram, and assesses the impact of hadron effects and volume exclusion on the quarkyonic phase.

Contribution

It introduces an entanglement vertex in the PNJL model and combines it with a hadron gas model to improve the description of QCD thermodynamics and phase structure.

Findings

EPNJL model reproduces lattice QCD data more accurately.

Hadron effects and volume exclusion influence the phase diagram.

The quarkyonic phase persists under various modeling conditions.

Abstract

The equation of state and the phase diagram in two-flavor QCD are investigated by the Polyakov-loop extended Nambu--Jona-Lasinio (PNJL) model with an entanglement vertex between the chiral condensate and the Polyakov-loop. The entanglement-PNJL (EPNJL) model reproduces LQCD data at zero and finite chemical potential better than the PNJL model. Hadronic degrees of freedom are taken into account by the free-hadron-gas (FHG) model with the volume-exclusion effect due to the hadron generation. The EPNJL+FHG model improves agreement of the EPNJL model with LQCD data particularly at small temperature. The quarkyonic phase survives, even if the correlation between the chiral condensate and the Polyakov loop is strong and hadron degrees of freedom are taken into account. However, the location of the quarkyonic phase is sensitive to the strength of the volume exclusion.