Accelerating cosmologies from non-local higher-derivative gravity

TL;DR

This paper develops a local formulation for non-local higher-derivative gravity theories, demonstrating their potential to unify early inflation and late-time cosmic acceleration.

Contribution

It introduces a local scalar field formulation for non-local Gauss-Bonnet gravity, enabling analysis of accelerating cosmologies and unification of inflation with late acceleration.

Findings

Non-local Gauss-Bonnet gravity can be reformulated as scalar-Gauss-Bonnet gravity.

The framework allows for models unifying early inflation and late-time acceleration.

The local formulation simplifies the analysis of complex higher-derivative gravity theories.

Abstract

We study accelerating cosmological solutions of a general class of non-linear gravities which depend on Gauss-Bonnet and other higher derivative invariants. To achieve this goal a local formulation with auxiliary scalars for arbitrary higher-derivative non-local gravity is developed. It is demonstrated that non-local Gauss-Bonnet gravity can be reduced, in the local formulation, to a model of string-inspired scalar-Gauss-Bonnet gravity. A natural unification, in the theory here developed, of the early-time inflation epoch with a late-time acceleration stage can also be realized.