The Renormalized Thermal Mass with Non-Zero Charge Density

Abstract

The linear $δ$ expansion is used to obtain corrections up to O$(δ^2)$ to the self-energy for a complex scalar field theory with a $λ(ϕ^{\star}ϕ)^2$ interaction at high temperature and non-zero charge density. The calculation is done in the imaginary-time formalism via the Hamiltonian form of the path integral. Nonperturbative results are generated by a systematic order by order variational procedure and the dependence of the critical temperature on the chemical potential $μ$ is obtained.