String Cosmology: An Update

Abstract

A string cosmology scenario ("pre-big-bang") postulates that the evolution of the Universe starts from a state of very small curvature and coupling, undergoes a long phase of dilaton-driven kinetic inflation and at some later time joins smoothly standard radiation dominated cosmological evolution, thus giving rise to a singularity free inflationary cosmology. I report on recent progress in understanding some outstanding issues such as initial conditions, graceful exit transition and generation of inhomogeneity perturbations.