Assisted inflation in Friedmann-Robertson-Walker and Bianchi spacetimes

Abstract

We use exact general solutions for the spatially flat FRW and the anisotropic Bianchi I cosmologies to show that generically uncoupled scalar fields cooperate to make inflation more probable, while the presence of several interacting fields hinders the occurrence of the phenomenon, in accordance with previous results based on particular power-law solutions. Similar conclusions are reached in the case of Bianchi VI${}_0$ spacetimes, for power-law solutions which are proved to be attractors.

2 eps figures. To appear in PRD