Accelerating Cosmologies in the Einstein-Gauss-Bonnet Theory with Dilaton

TL;DR

This paper investigates cosmological solutions within heterotic string theory incorporating Einstein gravity, Gauss-Bonnet term, and dilaton, focusing on fixed points and potential for accelerated expansion of our universe.

Contribution

It derives all fixed points of the autonomous system and analyzes the conditions for transient accelerated expansion in this theoretical framework.

Findings

Identification of fixed points in the cosmological system.

Conditions for transient acceleration in four-dimensional space.

Analysis of the evolution of solutions over time.

Abstract

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