De Sitter cosmology from Gauss-Bonnet dark energy with quantum effects

TL;DR

This paper investigates how quantum effects in a Gauss-Bonnet dark energy model inspired by string theory can induce a de Sitter phase, potentially explaining inflation and dark energy without classical constraints.

Contribution

It introduces quantum contributions from conformal anomaly into Gauss-Bonnet dark energy models, revealing new solutions and stability properties leading to de Sitter phases.

Findings

Quantum effects generate new Hubble rate solutions absent classically.

Quantum corrections influence the stability of solutions around the de Sitter point.

Quantum effects enable de Sitter stages even with positive coupling constants.

Abstract

A Gauss-Bonnet dark energy model is considered, which is inspired in string/M-theory and takes also into account quantum contributions. Those are introduced from a conformal quantum anomaly. The corresponding solutions for the Hubble rate, $H$, are studied starting from the Friedmann-Robertson-Walker equation. It is seen that, as a pure effect of the quantum contributions, a new solution for $H$ exists in some region, which does not appear in the classical case. The behavior of all encountered solutions is studied with care, in particular, the role played by the quantum correction term--which depends on the number of matter fields--on the stability of the solutions around its asymptotic value. It is argued that, contrary to what happens in the classical case, quantum effects remarkably lead to the realization of a de Sitter stage which corresponds to the inflation/dark energy stages, even for positive values of the f_0 constant (coupling of the field with the Gauss-Bonnet invariant).