Assisted inflation via tachyon condensation

In this paper we propose a new mechanism of inflating the Universe with non-BPS D4-branes which decay into stable D3-branes via tachyon condensation. In a single brane scenario the tachyon potential is very steep and unable to support inflation. However, if the universe lives in a stack of branes produced by a set of noninteracting unstable D4-branes, then the associated set of tachyons. may drive inflation along our 3 spatial dimensions. After tachyon condensation the Universe is imagined to be filled with a set of parallel stable D3-branes. We study the scalar density perturbations and reheating within this setup. (C) 2001 Elsevier Science B.V. All rights reserved.