We study anomalous Wess-Zumino couplings of D-branes and O-planes in a general background and derive them from a direct string computation by factorizing in the RR channel various one-loop amplitues.… (More)

We derive the general form of the anomaly for chiral spinors and self-dual antisymmetric tensors living on D-brane and O-plane intersections, using both path-integral and index theorem methods. We… (More)

We study higher-dimensional non-supersymmetric orbifold models where the Higgs field is identified with some internal component of a gauge field. We address two important and related issues that… (More)

A precise correspondence between freely-acting orbifolds (Scherk-Schwarz compactifications) and string vacua with NSNS flux turned on is established using T-duality. We focus our attention to a… (More)

We study string-gas cosmology in dilaton gravity, inspired by the fact that it naturally arises in a string theory context. Our main interest is the thermodynamical treatment of the stringgas and the… (More)

We study spin interactions between two moving D-branes using the GreenSchwarz formalism of boundary states. We focus our attention on the leading terms for small velocities v, of the form v4−n/r7−p+n… (More)

We employ the LSZ reduction formula for Matrix Theory introduced in our earlier work to compute the t-pole S-matrix for three form–three form scattering. The result agrees completely with tree level… (More)

We study examples of chiral four-dimensional IIB orientifolds with ScherkSchwarz supersymmetry breaking, based on freely acting orbifolds. We construct a new Z3 × Z3 model, containing only D9-branes,… (More)

We study under what conditions massive fields can be “frozen” rather than integrated out in certain four dimensional theories with global or local N = 1 supersymmetry. We focus on models without… (More)

Six-dimensional orbifold models where the Higgs field is identified with some internal component of a gauge field are considered. We classify all possible T /ZN orbifold constructions based on a… (More)