Seminar
A new asymptotic perturbation theory and applications to massless quantum field theories

Hold Date 
20130117 16:00～20130117 17:30 


Place 
Seminar Room 7, Faculty of Mathematics building, Ito Campus 


Object person 



Speaker 
ARAI, Asao (Hokkaido University) 

Abstract：
The standard analytic or asymptotic perturbation theory considers only perturbations of isolated eigenvalues. In this lecture, we present a new asymptotic perturbation theory which may be valid also for the case where the unperturbed operator has a nonisolated eigenvalue (important examples in which the unperturbed operator has nonisolated eigenvalues appear, e.g., in massless quantum field theories). As an application, we consider a quantum field model, called the generalized spinboson model (including the massless case), and, for its ground state energy, we derive an asymptotic expansion in the coupling constant up to an arbitrary finite order.