Modified gravity with negative and positive powers of the curvature: unification of the inflation and of the cosmic acceleration

TL;DR

This paper explores a modified gravity model with positive and negative curvature powers, unifying inflation and cosmic acceleration without dark energy, and demonstrating compatibility with solar system tests.

Contribution

It introduces a stable modified gravity framework that naturally explains both early universe inflation and current acceleration.

Findings

Supports inflation with positive curvature terms

Accounts for dark energy with negative curvature terms

Compatible with solar system experiments

Abstract

The modified gravity, which eliminates the need for dark energy and which seems to be stable, is considered. The terms with positive powers of the curvature support the inflationary epoch while the terms with negative powers of the curvature serve as effective dark energy, supporting current cosmic acceleration. The equivalent scalar-tensor gravity may be compatible with the simplest solar system experiments.