High Temperature Resummation in the Linear $\delta$-Expansion

TL;DR

This paper applies the optimized linear delta-expansion to high-temperature lambda phi^4 theory, calculating the thermal mass perturbatively and using a variational approach to determine the critical temperature for phase transition.

Contribution

It introduces a variational nonperturbative method within the linear delta-expansion framework for high-temperature field theory analysis.

Findings

Thermal mass evaluated up to order delta^2.

Critical temperature obtained via variational nonperturbative results.

Comparison with propagator dressing methods shows consistency.

Abstract

The optimized linear $\delta$-expansion is applied to the $\lambda \phi^4$ theory at high temperature. Using the imaginary time formalism the thermal mass is evaluated perturbatively up to order $\delta^2$. A variational procedure associated with the method generates nonperturbative results which are used to obtain the critical temperature for the phase transition. Our results are compared with the ones given by propagator dressing methods.