By looking at phase transitions which occur as parameters are varied in super-symmetric gauge theories, a natural relation is found between sigma models based on Calabi-Yau hypersurfaces in weightedâ€¦ (More)

By exploiting recent arguments about stable nonsupersymmetric D-brane states, we argue that D-brane charge takes values in the K-theory of spacetime, as has been suspected before. In the process, weâ€¦ (More)

The strong coupling dynamics of string theories in dimension d â‰¥ 4 are studied. It is argued, among other things, that eleven-dimensional supergravity arises as a low energy limit of theâ€¦ (More)

N = 2 supersymmetric gauge theories in four dimensions are studied by formulating them as the quantum field theories derived from configurations of fourbranes, fivebranes, and sixbranes in Type IIAâ€¦ (More)

Just as parallel threebranes on a smooth manifold are related to string theory on AdS5 Ã— S, parallel threebranes near a conical singularity are related to string theory on AdS5 Ã— X5, for a suitableâ€¦ (More)

It is shown that 2 + 1 dimensional quantum Yang-Mills theory, with an action consisting purely of the Chern-Simons term, is exactly soluble and gives a natural framework for understanding the Jonesâ€¦ (More)

In the mapping from four-dimensional gauge theories to string theory in AdS space, many features of gauge theory can be described by branes wrapped in different ways on S, RP, or subspaces therefore.â€¦ (More)

The correspondence between supergravity (and string theory) on AdS space and boundary conformal field theory relates the thermodynamics of J\f = 4 super Yang-Mills theory in four dimensions to theâ€¦ (More)

In this paper, we present a systematic analysis of eleven-dimensional supergravity on a manifold with boundary, which is believed to be relevant to the strong coupling limit of the E8Ã—E8 heteroticâ€¦ (More)

Certain two dimensional topological field theories can be interpreted as string theory backgrounds in which the usual decoupling of ghosts and matter does not hold. Like ordinary string models, theseâ€¦ (More)