2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/201519We study non-supersymmetric, extremal 4 dimensional black holes which arise upon compactification of type II superstrings on Calabi-Yau threefolds. We propose a generalization of the 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.47 pages, harvmac. v2: footnote(4) expanded, references addedHigh Energy Physics - Theorytext