Static N=2 Black Holes For Quadratic Prepotentials

We employ the principle of minimal central charge and study the entropy of N=2 black holes corresponding to the most general quadratic prepotential. We also give a static black hole solution for these models in which the scalar moduli are non constants. Finally, we speculate on the microscopic origin for our solution.Comment: 8 pages, Latex fil

Classification of Supersymmetric Flux Vacua in M Theory

We present a comprehensive classification of supersymmetric vacua of M-theory compactification on seven-dimensional manifolds with general four-form fluxes. We analyze the cases where the resulting four-dimensional vacua have N = 1,2,3,4 supersymmetry and the internal space allows for SU(2), SU(3) or G_2 structures. In particular, we find for N = 2 supersymmetry, that the external space-time is Minkowski and the base manifold of the internal space is conformally K\"ahler for SU(2) structures, while for SU(3) structures the internal space has to be Einstein-Sasaki and no internal fluxes are allowed. Moreover, we provide a new vacuum with N = 1 supersymmetry and SU(3) structure, where all fluxes are non-zero and the first order differential equations are solved.Comment: 50 pages, clarification of the spinor ansatz added, references added, typos correcte

Topological Objects in 5D Maxwell Einstein Supergravity

In this letter is shown that it is possible to obtain scalar hypersurfaces in 5D N=2 SUGRA where the allowed regions with positive definite scalar metric have a non-trivial topology. This situation may aid in the construction of domain wall solutions which confine gravity to 4 dimensions.Comment: 8 pages, 8 figures, accepted in PLB, reference adde

Non-extreme Calabi-Yau Black Holes

Non-extreme black hole solutions of four dimensional, N=2 supergravity theories with Calabi-Yau prepotentials are presented, which generalize certain known double-extreme and extreme solutions. The boost parameters characterizing the nonextreme solutions must satisfy certain constraints, which effectively limit the functional independence of the moduli scalars. A necessary condition for being able to take certain boost parameters independent is found to be block diagonality of the gauge coupling matrix. We present a number of examples aimed at developing an understanding of this situation and speculate about the existence of more general solutions.Comment: 10 pages of plain TeX. Uses harvmac

Black Holes and Rings of minimal 5-dim. Supergravity

In this talk, I will summarize recent developments in 5-dimensional supergravity. Apart from black ring solutions, we will discuss the way of obtaining regular (bubbling) solutions with the same charges as black holes. We outline the procedure for the solution in five and four dimensions. Finally we explore the close relationship between 4- and 5-dimensional supersymmetric stationary solutions.Comment: 9 pages, to appear in Proceedings of: RTN workshop: ``The quantum structure of space-time and the geometric nature of fundamental interactions'', Corfu, September 2005; improved ref