Spontaneous parity and charge-conjugation violations at real isospin and imaginary baryon chemical potentials

TL;DR

This paper explores the phase structure of two-flavor QCD at real isospin and imaginary baryon chemical potentials, revealing spontaneous parity and charge-conjugation violations linked to pion superfluidity and Roberge-Weiss transitions.

Contribution

It introduces an analysis of how parity and charge-conjugation symmetries are spontaneously broken in this regime using the PNJL model, and examines their interplay with chiral and deconfinement crossovers.

Findings

Parity symmetry is spontaneously broken by pion superfluidity.

Charge-conjugation symmetry is spontaneously violated by the Roberge-Weiss transition.

The chiral and deconfinement crossovers are remnants of these symmetry violations.

Abstract

The phase structure of two-flavor QCD is investigated at real isospin and imaginary quark chemical potentials by using the Polyakov-loop extended Nambu--Jona-Lasinio model. In the region, parity symmetry is spontaneously broken by the pion superfluidity phase transition, whereas charge-conjugation symmetry is spontaneously violated by the Roberge-Weiss transition. The chiral (deconfinement) crossover at zero isospin and quark chemical potentials is a remnant of the parity (charge-conjugation) violation. The interplay between the parity and charge-conjugation violations are analyzed, and it is investigated how the interplay is related to the correlation between the chiral and deconfinement crossovers at zero isospin and quark chemical potentials.