Accelerating cosmologies in the Einstein-Gauss-Bonnet theory with a dilaton

Abstract

We study cosmological solutions in low-energy effective heterotic string theory, which consists of the Einstein gravity with the Gauss-Bonnet term and a dilaton. We show that the field equations take the form of an autonomous system for flat internal and external spaces, and we derive all the fixed points in the system. We also examine the time evolution of the solutions and the question of whether the solutions can describe (transient) accelerated expansion of our four-dimensional space in the Einstein frame.