An Optimised Perturbation Expansion For a Global O(2) Theory

Abstract

We use an optimised perturbation expansion called the linear delta-expansion to study the phase transition in a Higgs sector with a continuous symmetry and large couplings. Our results show how to use this non-perturbative method successfully for such problems. We also show how to simplify the method without losing any flexibility.

Comments: LaTeX2e, 15 pages, 12 eps figures