Dark energy cosmology from higher-order, string-inspired gravity and its reconstruction

TL;DR

This paper explores how string-inspired higher-order gravity modifications can produce viable dark energy models, including quintessence, de Sitter, and phantom scenarios, without negative kinetic energy fields, and presents a reconstruction method for these models.

Contribution

It introduces a reconstruction framework for scalar-Gauss-Bonnet gravity with string corrections, enabling the modeling of various dark energy behaviors consistent with observations.

Findings

Higher-order string corrections can produce dark energy models compatible with observations.

The model can realize quintessence, de Sitter, or phantom dark energy without negative kinetic energy.

Explicit reconstructed scalar potentials for accelerated universes are provided.

Abstract

In this paper we investigate the cosmological effects of modified gravity with string curvature corrections added to Einstein-Hilbert action in the presence of a dynamically evolving scalar field coupled to Riemann invariants. The scenario exhibits several features of cosmological interest for late universe. It is shown that higher order stringy corrections can lead to a class of dark energy models consistent with recent observations. The model can give rise to quintessence, deSitter or phantom dark energy, in last case without recourse to negative kinetic energy field. The detailed treatment of reconstruction program for general scalar-Gauss-Bonnet gravity is presented for any given cosmology. The explicit examples of reconstructed scalar potentials are given for accelerated (quintessence, cosmological constant or phantom) universe. Finally, the relation with modified $F(G)$ gravity is established on classical level and is extended to include third order terms on curvature.