Updating the Phase Diagram of the Gross-Neveu Model in 2+1 Dimensions

TL;DR

This paper uses optimized perturbation theory to analyze the phase diagram of the massless Gross-Neveu model in 2+1 dimensions, confirming a tricritical point and first-order transition line suggested by prior lattice simulations.

Contribution

It applies optimized perturbation theory combined with Landau expansion to accurately determine critical points in the model's phase diagram, advancing theoretical understanding.

Findings

Confirmation of a tricritical point in the phase diagram

Identification of a line of first-order phase transitions

Methodology for calculating critical quantities

Abstract

The method of optimized perturbation theory (OPT) is used to study the phase diagram of the massless Gross-Neveu model in 2+1 dimensions. In the temperature and chemical potential plane, our results give strong support to the existence of a tricritical point and line of first order phase transition, previously only suspected to exist from extensive lattice Monte Carlo simulations. In addition of presenting these results we discuss how the OPT can be implemented in conjunction with the Landau expansion in order to determine all the relevant critical quantities.