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,R)/Z Wess-Zumino-Witten coset models. Four-dimensional spacetime solutions are obtained by tensoring these two-dimensional theories with $\frac{\mathrm{SU}\mathrm{}\left(2\right)\mathrm{}}{Z\left(m\right)\mathrm{}}$ coset models. These describe a family of dyonic black holes and the Bertotti-Robinson universe.