Roberge-Weiss phase transition and its endpoint

TL;DR

This paper analyzes the Roberge-Weiss phase transition using the PNJL model, revealing its second-order nature at the endpoint and its relation to deconfinement crossover at zero chemical potential.

Contribution

It provides a detailed analysis of the RW phase transition and its endpoint within the PNJL model, highlighting symmetry properties and the transition order.

Findings

RW phase transition is second order at the endpoint

Charge-conjugation symmetry is spontaneously broken in RW transition

Deconfinement crossover at zero chemical potential is related to the RW transition

Abstract

The Roberge-Weiss (RW) phase transition in the imaginary chemical potential region is analyzed by the Polyakov-loop extended Nambu--Jona-Lasinio (PNJL) model. In the RW phase transition, the charge-conjugation symmetry is spontaneously broken, while the extended Z3 symmetry (the RW periodicity) is preserved. The RW transition is of second order at the endpoint. At the zero chemical potential, a crossover deconfinement transition appears as a remnant of the second-order RW phase transition at the endpoint, while the charge-conjugation symmetry is always preserved.