The Composite Operator (CJT) Formalism in the $(\lambda\phi^4+\eta\phi^{6})_{D=3}$ Model at Finite Temperature

TL;DR

This paper applies the CJT formalism to analyze the finite-temperature behavior of a 3D $\,\lambda\phi^4+\eta\phi^6$ model, revealing a tricritical point through non-perturbative methods.

Contribution

It introduces a non-perturbative analysis of the 3D $\,\lambda\phi^4+\eta\phi^6$ model at finite temperature using the CJT formalism, identifying a tricritical point.

Findings

Identification of a tricritical point at a specific temperature.

Analysis of thermal mass and coupling constant behavior at different temperatures.

Application of the 1/N expansion and CJT formalism to a 3D scalar field theory.

Abstract

We discuss three-dimensional $ \lambda\phi^4+\eta\phi^6 $ theory in the context of the 1/N expansion at finite temperature. We use the method of the composite operator (CJT) for summing a large sets of Feynman graphs. We analyse the behavior of the thermal square mass and the thermal coupling constant in the low and high temperature limit. The existent of the tricritical point at some temperature is found using this non-pertubative method.