Dark energy problem: from phantom theory to modified Gauss-Bonnet gravity

TL;DR

This paper explores how modified Gauss-Bonnet gravity can explain late-time cosmic acceleration without scalar fields, using ideal fluids and predicting various acceleration regimes.

Contribution

It demonstrates that modified Gauss-Bonnet gravity can naturally produce different types of late-time acceleration, including phantom and quintessence, without scalar fields.

Findings

Modified Gauss-Bonnet gravity predicts late-time acceleration.

The approach can produce quintessence, cosmological constant, or phantom acceleration.

Transition from deceleration to acceleration is naturally explained.

Abstract

The solution of dark energy problem in the models without scalars is presented. It is shown that late-time accelerating cosmology may be generated by the ideal fluid with some implicit equation of state. The universe evolution within modified Gauss-Bonnet gravity is considered. It is demonstrated that such gravitational approach may predict the (quintessential, cosmological constant or transient phantom) acceleration of the late-time universe with natural transiton from deceleration to acceleration (or from non-phantom to phantom era in the last case).