Pair production of black holes in a U(1)⊗U(1) theory

Charged dilaton black hole solutions have recently been found for an action with two U(1) gauge fields and a dilaton field. I investigate new exact solutions of this theory analogous to the C metric and Ernst solutions of classical general relativity. The parameters in the latter solution may be restricted so that it has a smooth Euclidean section with toplogy ${\mathit{S}}^2$×${\mathit{S}}^2$-{pt}, which gives an instanton describing pair production of the charged dilaton black holes. These instantons generalize those found recently by Dowker and co-workers.