Non-supersymmetric black holes and topological strings

We study non-supersymmetric, extremal four-dimensional black holes which arise upon compactification of type II superstrings on Calabi Yau (CY) threefolds. We propose a generalization of the Ooguri Strominger Vafa (OSV) conjecture for higher-derivative corrections to the non-supersymmetric black hole entropy, in terms of the one-parameter refinement of topological string introduced by Nekrasov. We also study the attractor mechanism for non-supersymmetric black holes and show how the inverse problem of fixing charges in terms of the attractor value of CY moduli can be explicitly solved.