Roberge-Weiss transitions at imaginary isospin chemical potential

TL;DR

This paper explores the phase structure of QCD at imaginary isospin chemical potential, revealing Roberge-Weiss transitions and symmetry breaking through perturbative calculations and lattice simulations.

Contribution

It introduces a novel phase diagram for QCD with imaginary isospin chemical potential, combining perturbative analysis with lattice verification.

Findings

Identification of Roberge-Weiss transitions at imaginary isospin chemical potential

Development of a new phase diagram illustrating symmetry breaking

Validation of perturbative results with lattice simulations

Abstract

At finite imaginary values of the chemical potential, QCD is free of the sign problem. Moreover, at high temperatures the partition function exhibits a new symmetry (the Roberge-Weiss symmetry) connecting phases with different orientations of the Polyakov loop, and the corresponding phase transitions between these. In this contribution we investigate the perturbative one-loop effective potential for the Polyakov loop in the presence of imaginary isospin as well as baryon chemical potentials. This leads to a novel phase diagram, which reveals an interesting insight about the rich phase structure of the system and the center symmetry breaking. We check the perturbative results using direct lattice simulations.