Finite temperature quantum field theory in the functional Schrödinger picture.

Abstract

We calculate the finite temperature Gaussian effective potential of scalar ${\mathrm{\ensuremath{\varphi}}}^{4}$ theory in the functional Schr\odinger picture. Our method is the direct generalization of the variational method proposed by Eboli, Jackiw, and Pi for quantum-mechanical systems, and gives the same result as that of Amelino-Camelia and Pi who used the self-consistent composite operator method.