Gravitational and Axionic Backgrounds for Four-dimensional Superstrings
arXiv:hep-th/9312025
Abstract
We construct new four-dimensional superstring vacua with extended superconformal symmetries. A non-trivial dilaton background implies the existence of Abelian killing symmetries. These are used to construct dual equivalent backgrounds in a way preserving the N=2 superconformal invariance.
(Talk given at the EPS 93 Conference at Marseilles, 7 pages, HUB-IEP-93/7