We investigate a simple class of type II string compactifications which incorporate nongeometric “fluxes” in addition to “geometric flux” and the usual H-field and R-R fluxes. These compactifications… (More)

We consider the spectra of excitations around diagonal and intersecting D-brane configurations on tori. These configurations are described by constant curvature connections in a dual gauge theory… (More)

We investigate further our recent proposal for the form of the matrix theory action in weak background fields. Using Seiberg’s scaling argument we relate the matrix theory action to a low-energy… (More)

We show that the linearized supergravity potential between two objects arising from the exchange of quanta with zero longitudinal momentum is reproduced to all orders in 1/r by terms in the one-loop… (More)

We consider type II string theory compactified on a symmetric T /Z2 orientifold. We study a general class of discrete deformations of the resulting fourdimensional supergravity theory, including… (More)

We prove that inflation is forbidden in the most well understood class of semi-realistic type IIA string compactifications: Calabi-Yau compactifications with only standard NS-NS 3-form flux, R-R… (More)

We present a construction in Matrix theory of longitudinal 5-branes whose geometry in transverse space corresponds to a 4-sphere. We describe these branes through an explicit construction in terms of… (More)

We consider membranes of spherical topology in uncompactified Matrix theory. In general for large membranes Matrix theory reproduces the classical membrane dynamics up to 1/N corrections; for certain… (More)

We calculate the leading term in the low-energy absorption cross section for an arbitrary partial wave of the dilaton field by a stack of many coincident D3-branes. We find that it precisely… (More)