Modified Gauss-Bonnet theory as gravitational alternative for dark energy

TL;DR

This paper proposes a modified gravity theory involving a function of the Gauss-Bonnet term as an alternative explanation for dark energy, capable of explaining late-time cosmic acceleration and passing solar system tests.

Contribution

It introduces a new modified gravity model based on the Gauss-Bonnet term that can account for dark energy phenomena and aligns with solar system constraints.

Findings

The theory can reproduce late-time cosmic acceleration.

It allows crossing the phantom divide.

It passes solar system tests.

Abstract

We suggest the modified gravity where some arbitrary function of Gauss-Bonnet (GB) term is added to Einstein action as gravitational dark energy. It is shown that such theory may pass solar system tests. It is demonstrated that modified GB gravity may describe the most interesting features of late-time cosmology: the transition from deceleration to acceleration, crossing the phantom divide, current acceleration with effective (cosmological constant, quintessence or phantom) equation of state of the universe.