The three-dimensional, three state Potts model in a negative external field

TL;DR

This study explores the phase transition behavior of the 3D three-state Potts model under a negative external field, identifying a tricritical point and its implications for QCD phase diagram analogies.

Contribution

It provides a precise determination of the tricritical field in the 3D three-state Potts model with a negative external field, linking it to QCD phase studies.

Findings

First/second order transition change at the tricritical point

Precise value of the tricritical external field h_tric

Comparison with previous studies and relevance to QCD

Abstract

We investigate the critical behaviour of the three-dimensional, three state Potts model in presence of a negative external field h, i.e. disfavouring one of the three states. A genuine phase transition is present for all values of |h|, corresponding to the spontaneous breaking of a residual Z_2 symmetry. The transition is first/second order respectively for small/large values of |h|, with a tricritical field h_tric separating the two regimes. We provide, using different and consistent approaches, a precise determination of h_tric; we also compare with previous studies and discuss the relevance of our investigation to analogous studies of the QCD phase diagram in presence of an imaginary chemical potential.