Remarks on generalized Gauss-Bonnet dark energy

TL;DR

This paper explores modified gravity models with F(R,G) Lagrangian, showing they can naturally produce cosmic acceleration and phantom-divide-line crossing, with quantum effects potentially inducing transitions absent classically.

Contribution

It demonstrates that F(R,G) gravity models can account for cosmic acceleration and quantum effects can induce transitions in these models.

Findings

Phantom-divide-line crossing occurs in F(R,G) models.

Quantum effects can induce transitions absent classically.

Results align with known f(R) and f(G) gravity models.

Abstract

The modified gravity with F(R,G) Lagrangian, G is the Gauss-Bonnet invariant, is considered. It is shown that the phantom-divide-line crossing and the deceleration to acceleration transition generally occur in these models. Our results coincide with the known results of f(R)-gravity and f(G)-gravity models. The contribution of quantum effects to these transitions is calculated, and it is shown that in some special cases where there are no transitions in classical level, quantum contributions can induce transitions. The quantum effects are described via the account of conformal anomaly.