We discuss the relation between the Ramond-Ramond charges of D-branes and the topology of Chan-Paton vector bundles. We show that a topologically nontrivial normal bundle induces RR charge and thatâ€¦ (More)

We characterize N = 1 vacua of type II theories in terms of generalized complex structure on the internal manifold M . The structure group of T (M)âŠ•T (M) being SU(3)Ã—SU(3) implies the existence ofâ€¦ (More)

We show that the supersymmetry transformations for type II string theories on six-manifolds can be written as differential conditions on a pair of pure spinors, the exponentiated KÃ¤hler form e andâ€¦ (More)

We exhibit a one-parameter family of regular supersymmetric solutions of type IIB theory that interpolates between Klebanov-Strassler (KS) and Maldacena-NuÃ±ez (MN). The solution is obtained byâ€¦ (More)

Supersymmetric configurations of type II D-branes with nonzero gauge field strengths in general supersymmetric backgrounds with nonzero B fields are analyzed using the Îºsymmetric worldvolume action.â€¦ (More)

We perform a systematic search for N = 1 Minkowski vacua of type II string theories on compact sixâ€“dimensional parallelizable nilâ€“ and solvmanifolds (quotients of sixâ€“dimensional nilpotent andâ€¦ (More)

Membrane/fivebrane duality in D = 11 implies Type IIA string/Type IIA fivebrane duality in D = 10, which in turn implies Type IIA string/heterotic string duality in D = 6. To test the conjecture, weâ€¦ (More)

We study loop corrections to the universal dilaton supermultiplet for type IIA strings compactified on Calabi-Yau threefolds. We show that the corresponding quaternionic kinetic terms receiveâ€¦ (More)

We discuss several implications of R couplings in M theory when compactified on Calabi-Yau (CY) manifolds. In particular, these couplings can be predicted by supersymmetry from the mixedâ€¦ (More)

We study gravitational anomalies for fivebranes in M theory. We show that an apparent anomaly in diffeomorphisms acting on the normal bundle is cancelled by a careful treatment of the M theoryâ€¦ (More)