G-flux, M5 instantons, andU(1)symmetries inF-theory

M Theory , Orientifolds and G - Flux

We study the properties of M and F theory compactifications to three and four dimensions with background fluxes. We provide a simple construction of supersymmetric vacua, including some with orientifold descriptions. These vacua, which have warp factors, typically have fewer moduli than conventional Calabi-Yau compactifications. The mechanism for anomaly cancellation in the orientifold models i...

Perturbation Theory with Instantons

The large k asymptotics (perturbation series) for integrals of the form ∫ F μe ikS , where μ is a smooth top form and S is a smooth function on a manifold F , both of which are invariant under the action of a symmetry group G, may be computed using the stationary phase approximation. This perturbation series can be expressed as the integral of a top form on the space M of critical points of S m...

M5-brane in three-form flux and multiple M2-branes

We investigate the Bagger-Lambert-Gustavsson model associated with the Nambu-Poisson algebra as a theory describing a single M5-brane. We argue that the model is a gauge theory associated with the volumepreserving diffeomorphism in the three-dimensional internal space. We derive gauge transformations, actions, supersymmetry transformations, and equations of motions in terms of six-dimensional f...

Some Comments on Branes, G-flux, and K-theory

This talk was divided into 3 parts. In each part we describe how considerations related to D-branes and RR fields of type II string theory naturally lead to mathematics related to K-theory. Part one reviews some work done with D.-E. Diaconescu and E. Witten, and reported in . Here we review the way K-theory theta functions are related to M-theory partition functions. Part two reports on some wo...

Small Instantons in Matrix Theory