Exact four-dimensional dyonic black holes and Bertotti-Robinson spacetimes in string theory.

Conformal field theories corresponding to two–dimensional electrically charged black holes and to two–dimensional anti–de Sitter space with a covariantly constant electric field are simply constructed as SL(2, IR)/ZZ WZW coset models. The two–dimensional electrically charged black holes are related by Kaluza–Klein reduction to the 2+1–dimensional rotating black hole of Bañados, Teitelboim and Zanelli, and our construction is correspondingly related to its realization as a WZW model. Four–dimensional spacetime solutions are obtained by tensoring these two–dimensional theories with SU(2)/Z(m) coset models. These describe a family of dyonic black holes and the Bertotti–Robinson universe.