On the vacuum structure of type II string compactifications on Calabi-Yau spaces with H-fluxes

We discuss the vacuum structure of type IIA/B Calabi-Yau string compactifications to four dimensions in the presence of n-form H-fluxes. These will lift the vacuum degeneracy in the Calabi-Yau moduli space, and for generic points in the moduli space, N = 2 supersymmetry will be broken. However, for certain 'aligned' choices of the H-flux vector, supersymmetric ground states are possible at the degeneration points of the Calabi-Yau geometry. We will investigate in detail the H-flux induced superpotential and the corresponding scalar potential at several degeneration points, such as the Calabi-Yau large volume limit, the conifold loci, the Seiberg-Witten points, the strong coupling point and the conformal points. Some emphasis is given to the question whether partial supersymmetry breaking can be realized at those points. We also relate the H-flux induced superpotential to the formalism of gauged Ar = 2 supergravity. Finally, we point out the analogies between the Calabi-Yau vacuum structure due to H-fluxes and the attractor formalism of Ar = 2 black holes. (C) 2001 Published by Elsevier Science B.V.