On Modified Gravity

TL;DR

This paper explores nonlocal modified gravity models with specific ansatzes, deriving solutions for the scalar curvature in FLRW cosmology, including bounce solutions and late-time behaviors.

Contribution

It introduces new solutions in nonlocal gravity with the ansatz ox R = c R^mma, expanding understanding of cosmological scenarios in such models.

Findings

Derived explicit R(t) solutions for flat FLRW metric.

Found singular and nonsingular bounce solutions.

Identified conditions for late-time deceleration and special cases like R(t)=0.

Abstract

We consider some aspects of nonlocal modified gravity, where nonlocality is of the type $R \mathcal{F}(\Box) R$. In particular, using ansatz of the form $\Box R = c R^\gamma,$ we find a few $R(t)$ solutions for the spatially flat FLRW metric. There are singular and nonsingular bounce solutions. For late cosmic time, scalar curvature R(t) is in low regime and scale factor a(t) is decelerated. R (t) = 0 satisfies all equations when k = -1.