Application of a modified mean-field method to a gauge-invariant variational calculation

Abstract

A previously described variational approach turns a gauge problem into a global symmetric equivalent model. The use in the latter of a mean-field method with an effective dimensionality is shown to give agreement with the low- and high-temperature expansions. We apply this method to the Z( 2) gauge and matter field model in any dimension finding in particular that it quantitatively improves the results for the (2 + 1 ) dimensional case.