Departamento de Fisica Teorica, Universidad de Zaragoza.
50009 Zaragoza, Spain

E-mail: javierc@posta.unizar.es
 
The euclidean propagator in quantum models with non-equivalent instantons

Abstract:
We consider in detail the euclidean propagator in quantum-mechanical models which include the existence of non-equivalent instantons. For such a purpose we resort to the semiclassical approximation in order to take into account the fluctuations over the instantons themselves. The physical effects of the multi-instanton configurations appear in terms of the alternate dilute-gas approximation.