Recombination of Intersecting D-Branes and Cosmological Inflation

Abstract

We consider the interactions between Dp-branes intersecting at an arbitrary number of angles in the context of type II string theory. For cosmology purposes we concentrate in the theory on R^{3,1} x T^6. Interpreting the distance between the branes as the inflaton field, the branes can intersect at most at two angles on the compact space. If the configuration is non-supersymmetric we will have an interbrane potential that provides an effective cosmological inflationary epoch at the four dimensional intersection between the branes. The end of inflation occurs when the interbrane distance becomes small compared with the string scale, where a tachyon develops triggering the recombination of the branes. We study this recombination due to tachyon instabilities and we find the possibility for the final configuration to be again branes intersecting at two angles. This preserves the interesting features that are present in the intersecting brane models from the string model building point of view also after the end of inflation. This fact was not present in the models of branes intersecting at just one angle. This kind of recombination can be also important in other string contexts.