Nonperturbative calculation of symmetry breaking in quantum field theory

A new version of the δ expansion is presented, which, unlike the conventional δ expansion, can be used to do nonperturbative calculations in a self-interacting scalar quantum field theory having broken symmetry. We calculate the expectation value of the scalar field to first order in $\delta$, where $\delta$ is a measure of the degree of nonlinearity in the interaction term.