Emergent Universe Scenario in the Einstein-Gauss-Bonnet Gravity with Dilaton

TL;DR

This paper explores emergent universe solutions within Einstein-Gauss-Bonnet gravity coupled with a dilaton, showing how these terms influence early and late universe dynamics and comparing the model with supernova data.

Contribution

It presents new cosmological solutions demonstrating emergent universe scenarios in Einstein-Gauss-Bonnet gravity with a dilaton, including the role of coupling parameters and potential.

Findings

Gauss-Bonnet terms influence early and late universe evolution.

The model's emergent universe scenario can fit supernova data.

The Einstein static universe solution is unstable.

Abstract

We obtain cosmological solutions which admit emergent universe (EU) scenario in the framework of Einstein Gauss-Bonnet gravity coupled with a dilaton field in four dimensions. The coupling parameter of the Gauss-Bonnet terms and the dilaton in the theory are determined for obtaining an EU scenario. The corresponding dilaton potential which admits such scenario is determined. It is found that the Gauss- Bonnet (GB) terms coupled with a dilaton field plays an important role in describing the dynamics of the evolution of the early as well as the late universe. We note an interesting case where the GB term dominates initially in the asymptotic past regime, subsequently it decreases and thereafter its contribution in determining the dynamics of the evolution dominates once again. We note that the Einstein static universe solution permitted here is unstable which the asymptotic EU might follow. We also compare our EU model with supernova data.