On the Stability of Non-Supersymmetric Quantum Attractors in String Theory

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.Comment: References Added, Typos Corrected, Appendix A.2 Reordere

N=2 Conformal Superspace in Four Dimensions

We develop the geometry of four dimensional N=2 superspace where the entire conformal algebra of SU(2,2|2) is realized linearly in the structure group rather than just the SL(2,C) x U(2)_R subgroup of Lorentz and R-symmetries, extending to N=2 our prior result for N=1 superspace. This formulation explicitly lifts to superspace the existing methods of the N=2 superconformal tensor calculus; at the same time the geometry, when degauged to SL(2,C) x U(2)_R, reproduces the existing formulation of N=2 conformal supergravity constructed by Howe.Comment: 43 pages; v2 references added, acknowledgments update

Electric and magnetic charges in N=2 conformal supergravity theories

General Lagrangians are constructed for N=2 conformal supergravity theories in four space-time dimensions involving gauge groups with abelian and/or non-abelian electric and magnetic charges. The charges are encoded in the gauge group embedding tensor. The scalar potential induced by the gauge interactions is quadratic in this tensor, and, when the embedding tensor is treated as a spurionic quantity, it is formally covariant with respect to electric/magnetic duality. This work establishes a general framework for studying any deformation induced by gauge interactions of matter-coupled N=2 supergravity theories. As an application, full and residual supersymmetry realizations in maximally symmetric space-times are reviewed. Furthermore, a general classification is presented of supersymmetric solutions in $\mathrm{AdS}_2\times S^2$ space-times. As it turns out, these solutions allow either eight or four supersymmetries. With four supersymmetries, the spinorial parameters are Killing spinors of $\mathrm{AdS}_2$ that are constant on $S^2$, so that they carry no spin, while the bosonic background is rotationally invariant.Comment: 49 pages, typos correcte