Variational approach to thermal masses in compactified models

TL;DR

This paper uses a variational method to study thermal masses and phase transitions in a 5D scalar model with compactification, comparing results with one-loop calculations and analyzing phase transition characteristics.

Contribution

It introduces a variational approach to analyze thermal effects in higher-dimensional models, providing insights beyond traditional one-loop methods.

Findings

Thermal masses depend on the Wilson line phase.

The variational approach yields results consistent with one-loop calculations.

The nature of the phase transition is characterized in the model.

Abstract

We investigate by means of a variational approach the effective potential of a 5D U(1) scalar model at finite temperature and compactified on S^1 and S^1/Z_2 as well as the corresponding 4D model obtained through a trivial dimensional reduction. We are particularly interested in the behaviour of the thermal masses of the scalar field with respect to the Wilson line phase and the results obtained are compared with those coming from a one-loop effective potential calculation. We also explore the nature of the phase transition.