A (varying power)-law modified gravity

Abstract

In the present paper we analyze a toy model for an $f(\varphi ,R)$ gravity which has the form of a power-law modified gravity in which the exponent is space-time dependent. Namely, we investigate the effects of adding to the Hilbert-Einstein action an $R^{\varphi }$-term. We present possible equivalences of the model with known models of modified gravity theories and examine the problem of matter stability in this model. Like $f(R)$-gravity toy models, the present one offers the possibility of unifying the early and the late-time evolution of the Universe. We show that the behavior of the scalar field depends globally on the size of the Universe and locally on the surrounding environment. For the early Universe it lets appear a huge cosmological constant that might drive inflation. For the late-times it lets appear globally a tiny cosmological constant.

6 pages, 1 figure

References in corpus (4)

• Unified cosmic history in modified gravity: from F(R) theory to Lorentz non-invariant models
• Conditions for the cosmological viability of f(R) dark energy models
• Are f(R) dark energy models cosmologically viable ?
• Low surface brightness galaxies rotation curves in the low energy limit of $R^n$ gravity : no need for dark matter?

Cited by in corpus (6)

• Noether charge and black hole entropy in teleparallel gravity
• Anisotropic LRS-BI Universe with $f(Q)$ gravity theory
• $f(R)$-Modified Gravity, Wald Entropy, and the Generalized Uncertainty Principle
• Density perturbations in $f(R,\varphi )$-gravity with an application to the (varying power)-law model
• Radiative Corrections in the (Varying Power)-Law Modified Gravity
• Modified gravity from an entropy functional