Construction of String Solutions around Non-trivial Backgrounds

Abstract

We present a way of constructing string solutions around non-trivial gravitational backgrounds. The proposed solutions are constructed using $N=4$ superconformal building blocks with $\hat{c}=4$. We give two different and inequivalent realizations of non-trivial four-dimensional subspaces, and we show the emergence of the $N=4$ globally defined superconformal symmetry. The existence of $N=4$ world-sheet symmetry stabilizes our solutions and implies in target space a number of covariantized supersymmetries around space-time dependent gravitational and dilaton backgrounds.

Latex file, 15pp, CERN-TH.6790/93