Boundary conditions in quantized fields

Abstract

In this project we intend to study the effects imposed by boundary conditions on quantized fields, submitted to external fields. More specifically, we intend to construct exact effective actions at one loop level for Quantum Field Theory (QFT) inspired models under boundary conditions and analyze the vacuum stability of the models. Initially, we will work in analogy between QFT on non-simply connected space-time and QFT at finite temperature in the Matsubara formalism. The influence of boundary conditions on the vacuum expectation value of the fermion number under the action of classical backgrounds fields with topological configurations, mainly in models with gauge invariance in 2+1 dimensions, will also be considered. We also investigate the relevance of surface counter-terms in the calculation of radiative corrections to the Casimir energy, particularly in the theory with Neumman boundary conditions.