We discuss non-supersymmetric attractors with an instanton correction in Type IIA string theory compactified on a Calabi-Yau three-fold at large volume. For a stable non-supersymmetric black hole, the attractor point must minimize the effective black hole potential. We study the supersymmetric as well as non-supersymmetric attractors for the D0-D4 system with instanton corrections. We show that in simple models, like the STU model, the flat directions of the mass matrix can be lifted by a suitable choice of the instanton parameters. * email: pramod@physics.iitm.ac.in † email: prasanta@physics.iitm.ac.in arXiv:1010.3373v2 [hep-th] 11 Nov 2010 c X 0 , (2.9)

In this paper we study spherically symmetric single-centered attractors in N = 2 supergravity in four dimensions. The attractor points are obtained by extremising the effective black hole potential in the moduli space. Both supersymmetric as well as non-supersymmetric attractors exist in mutually exclusive domains of the charge lattice. We construct axion free supersymmetric as well as non-supersymmetric multiple attractors in a simple two parameter model. We further obtain explicit examples of two distinct nonsupersymmetric attractors in type IIA string theory compactified on K3 × T 2 carrying D0 − D4 − D6 charges. We compute the entropy of these attractors and analyse their stability in detail.

In this paper we examine the stability of non-supersymmetric attractors in type IIA supergravity compactified on a Calabi-Yau manifold, in the presence of sub-leading corrections to the N = 2 pre-potential. We study black hole configurations carrying D0 − D6 and D0 − D4 charges.We consider the O(1) corrections to the pre-potential given by the Euler number of the Calabi-Yau manifold. We argue that such corrections in general can not lift the zero modes for the D0 − D6 attractors. However, for the attractors carrying the D0− D4 charges, they affect the zero modes in the vector multiplet sector. We show that, in the presence of such O(1) corrections, the D0 − D4 attractors can either be stable or unstable depending on the geometry of the underlying Calabi-Yau manifold, and on the specific values of the charges they carry. *

We study four dimensional non-supersymmetric attractors in type IIA string theory in the presence of sub-leading corrections to the prepotential. For a given Calabi-Yau manifold, the D0 − D4 system admits an attractor point in the moduli space which is uniquely specified by the black hole charges. The perturbative corrections to the prepotential do not change the number of massless directions in the black hole effective potential. We further study non-supersymmetric D0 − D6 black holes in the presence of sub-leading corrections. In this case the space of attractor points define a hypersurface in the moduli space. *