Effective potential in the BET formalism

TL;DR

This paper computes a non-perturbative one-loop effective potential at finite temperature for massless scalar fields using the boundary effective theory formalism, revealing differences from standard results for large field values.

Contribution

It introduces a non-perturbative calculation of the effective potential within the BET formalism, highlighting differences from traditional methods at high field values.

Findings

The effective potential differs from standard results for field values > T/√λ.

The method relies on classical solutions and Gaussian fluctuations.

The approach provides a non-perturbative perspective on finite-temperature scalar fields.

Abstract

We calculate the one-loop effective potential at finite temperature for a system of massless scalar fields with quartic interaction $\lambda\phi^4$ in the framework of the boundary effective theory (BET) formalism. The calculation relies on the solution of the classical equation of motion for the field, and Gaussian fluctuations around it. Our result is non-perturbative and differs from the standard one-loop effective potential for field values larger than $T/\sqrt{\lambda}$.