String and Mtheory cosmological solutions with Ramond forms
Abstract
A general framework for studying a large class of cosmological solutions of the lowenergy limit of type II string theory and of Mtheory, with nontrivial Ramond form fields excited, is presented. The framework is applicable to spacetimes decomposable into a set of flat or, more generally, maximally symmetric spatial subspaces, with multiple nontrivial form fields spanning one or more of the subspaces. It is shown that the corresponding lowenergy equations of motion are equivalent to those describing a particle moving in a moduli space consisting of the scale factors of the subspaces together with the dilaton. The choice of which form fields are excited controls the potential term in the particle equations. Two classes of exact solutions are given, those corresponding to exciting only a single form and those with multiple forms excited which correspond to Toda theories. Although typically these solutions begin or end in a curvature singularity, there is a subclass with positive spatial curvature which appears to be singularity free. Elements of this class are directly related to certain black pbrane solutions.
 Publication:

Nuclear Physics B
 Pub Date:
 February 1997
 DOI:
 10.1016/S05503213(97)001946
 arXiv:
 arXiv:hepth/9610238
 Bibcode:
 1997NuPhB.495..365L
 Keywords:

 High Energy Physics  Theory
 EPrint:
 34 pages, Latex, 3 figures using epsf