Expanding the thermodynamical potential and the analysis of the possible phase diagram of deconfinement in FL model

TL;DR

This paper investigates the deconfinement phase transition in the FL model at finite temperature and chemical potential, exploring the conditions for first and second order transitions and the potential phase diagram including a tricritical point.

Contribution

It introduces a Landau expansion analysis to identify conditions for second order phase transitions and proposes a phase diagram with both transition types in the FL model.

Findings

First order transition dominates in MFT approximation.

High order fluctuations can cancel the cubic term, enabling second order transitions.

A phase diagram with tricritical point similar to chiral transition is proposed.

Abstract

The deconfinement phase transition is studied in the FL model at finite temperature and chemical potential. At MFT approximation, the phase transition can only be the first order in the whole $\mu-T$ phase plane. By a Landau expansion we further study the phase transition order and the possible phase diagram of deconfinement. We discuss the possibilities of second order phase transitions in FL model. By our analysis the cubic term in the Landau expansion could be cancelled by the high order fluctuations. By an ansatz of the Landau parameters, we obtain the possible phase diagram with both first and second order phase transition including the tricritical point which is similar to that of the chiral phase transition.