QCD phase diagram at imaginary baryon and isospin chemical potentials

TL;DR

This paper investigates the phase diagram of two-flavor QCD at imaginary baryon and isospin chemical potentials using analytical methods and the PNJL model, revealing symmetry properties and qualitative agreement with recent lattice data.

Contribution

It provides a combined analytical and numerical analysis of the QCD phase diagram at imaginary chemical potentials, highlighting symmetry features and model-data consistency.

Findings

QCD has no pion condensation at imaginary chemical potentials

The PNJL model reproduces qualitative lattice QCD data

Discrete symmetries are present at imaginary chemical potentials

Abstract

We explore the phase diagram of two-flavor QCD at imaginary values of baryon and isospin chemical potentials analyzing the thermodynamic potential of QCD analytically and that of the Polyakov-loop extended Nambu-Jona-Lasinio (PNJL) model numerically. QCD has no pion condensation at imaginary baryon and isospin chemical potentials, and therefore has discrete symmetries that are not present at real baryon and isospin chemical potentials. The PNJL model possesses all the discrete symmetries. The PNJL model can reproduce qualitatively lattice QCD data presented very lately.