A New Model of Nonlocal Modified Gravity

TL;DR

This paper introduces a novel nonlocal modified gravity model involving an inverse Ricci scalar and a function of the d'Alembertian operator, aiming to find exact cosmological solutions using specific ansatz.

Contribution

It proposes a new nonlocal gravity model with a quadratic ansatz for the Ricci scalar, expanding the class of exact solutions in modified gravity theories.

Findings

Derived exact cosmological solutions under the quadratic ansatz.

Explored the implications of nonlocal terms on cosmological dynamics.

Provided a framework for further analysis of nonlocal gravity models.

Abstract

We consider a new modified gravity model with nonlocal term of the form $R^{-1} \mathcal{F}(\Box) R. $ This kind of nonlocality is motivated by investigation of applicability of a few unusual ans\"atze to obtain some exact cosmological solutions. In particular, we find attractive and useful quadratic ansatz $\Box R = q R^{2}.$