Heterotic Cosets

Abstract

A description is given of how to construct $(0,2)$ supersymmetric conformal field theories as coset models. These models may be used as non--trivial backgrounds for Heterotic String Theory. They are realised as a combination of an anomalously gauged Wess--Zumino--Witten model, right--moving supersymmetric fermions, and left--moving current algebra fermions. Requiring the sum of the gauge anomalies from the bosonic and fermionic sectors to cancel yields the final model. Applications discussed include exact models of extremal four--dimensional charged black holes and Taub--NUT solutions of string theory. These coset models may also be used to construct important families of $(0,2)$ supersymmetric Heterotic String compactifications. The Kazama--Suzuki models are the left--right symmetric special case of these models.