Phase structure of hadronic and Polyakov-loop extended NJL model at finite isospin density

TL;DR

This paper investigates the phase transitions in QCD at finite temperature and isospin density using hadronic and Polyakov-loop extended NJL models, revealing critical points and isospin effects on the phase diagram.

Contribution

It extends the study of QCD phase structure by analyzing the hadron-quark transition and critical points with isospin effects using advanced models.

Findings

Identification of phase boundaries and critical points

Significant isospin effects on phase structure

Analysis of the critical endpoint in the Polyakov-loop NJL model

Abstract

It is believed that there exists a rich phase structure of quantum chromodynamics (QCD) at finite temperature and baryon density, namely, the deconfinement process from hadron gas to quark-gluon plasma, the transition from chiral symmetry breaking phase to the symmetry restoration phase, and the color superconductivity at low temperature and high baryon density. In the present work we study the hadron-quark phase transition by investigating the binodal surface and extending it to finite temperature in order to mimic the QCD phase diagram. In order to obtain these conditions we use different models for the two possible phases, namely the quark and hadron phases. The phase separation boundary (binodal) is determined by the Gibbs criteria for phase equilibrium. The boundaries of the mixed phase and the related critical points for symmetric and asymmetric matter are obtained. Isospin effects appear to be rather significant. The critical endpoint (CEP) and the phase structure are also studied in the Polyakov-loop extended Nambu-Jona-Lasinio model.