Screened perturbation theory at four loops

TL;DR

This paper applies screened perturbation theory to massless phi-fourth theory, calculating thermodynamic quantities up to four loops and demonstrating improved convergence over traditional weak-coupling methods.

Contribution

It introduces a four-loop calculation of thermodynamics using screened perturbation theory, showing enhanced convergence properties.

Findings

Convergence is significantly improved compared to weak-coupling expansion.

Thermodynamic quantities are computed up to order g^7.

The method systematically reorganizes the perturbative series.

Abstract

We study the thermodynamics of massless phi-fourth theory using screened perturbation theory, which is a way to systematically reorganise the perturbative series. The free energy and pressure are calculated through four loops in a double expansion in powers of g^2 and m/T, where m is a thermal mass of order gT. The result is truncated at order g^7. We find that the convergence properties are significantly improved compared to the weak-coupling expansion.