Strings interactions in gravitational wave backgrounds

by D'appollonio, Giuseppe

Abstract

In this talk I will present the computation of the three and the four point functions for a WZW model based on a non-compact non-semisimple group. I will discuss the role of the spectral flowed representations and some other generic features of these models. I will also show that they can be considered as contraction of semisimple WZW model. From the space time point of view, the contraction amounts to a Penrose limit and in the final part of the talk I will discribe the behaviour of string theory in the corresponding gravitational wave background.