On Modified Gravity

Abstract

We consider some aspects of nonlocal modified gravity, where nonlocality is of the type $R\mathcal{F}(\square )R$. In particular, using ansatz of the form $\square R=c{R}^{\gamma },$ 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.

added references; made some clarifications; 8 pages

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• Route to nonlocal cosmology
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• On Nonlocal Modified Gravity and its Cosmological Solutions
• Cosmological solutions in modified gravity with monomial nonlocality
• On Nonlocal Modified Gravity and Cosmology
• Variations of Infinite Derivative Modified Gravity
• A New Model of Nonlocal Modified Gravity
• Revisiting cosmological diffusion models in Unimodular Gravity and the $H_0$ tension
• Dark energy with oscillatory tracking potential: Observational Constraints and Perturbative effects