Calculating boson and fermion loops in 3+1 dimensions and the derivative expansion.

Abstract

We extend our work on the numerical calculation of one-loop quantum corrections from two to four space-time dimensions, using a Green's-function technique. Studying time-independent, spherically symmetric background fields, we illustrate this method by calculating one-boson-loop and one-fermion-loop quantum corrections to the energy. We use our results to test derivative expansions and illuminate their convergence properties.