Cosmological reconstruction and energy bounds in $$f(R,R_{\alpha \beta }R^{\alpha \beta },\phi )$$ f ( R , R α β R α β , ϕ ) gravity

Abstract

We discuss the cosmological reconstruction of f (R, R αβ R αβ , φ) (where R, R αβ R αβ , and φ represent the Ricci scalar, the Ricci invariant, and the scalar field) corresponding to a power law and de Sitter evolution in the framework of the FRW universe model. We derive the energy conditions for this modified theory which seem to be more general and can be reduced to some well-known forms of these conditions in general relativity, f (R) and f (R, φ) theories. We have presented the general constraints in terms of recent values of the snap, jerk, deceleration, and Hubble parameters. The energy bounds are analyzed for reconstructed as well as known models in this theory. Finally, the free parameters are analyzed comprehensively.

Existence of stable wormholes on a non-commutative-geometric background in modified gravity

“…Some other well-known examples include Brans-Dicke gravity, generalized scalar-tensor theory, f (τ ) gravity, where τ is a torsion, Gauss-Bonnet gravity and its generalized forms like f (G) gravity, f (R, G) gravity, and f (τ, τ G ) theory, etc. [17][18][19][20][21][22][23][24][25][26].…”

Dynamics of scalar potentials in theory of gravity

“…We have derived the general form of f (R, Y, ϕ) for dS-model in [58], here we use this form to evaluate the scalar field potential. For this model, function f is defined as…”

“…Now we are utilizing f (R, ϕ) model, independent of Y which we have already constructed in the paper [58] and it is given by…”

“…Here we explore the nature of field potential for f (Y, ϕ) model, independent of R that is constructed in [58]. It has the following form…”

“…Sharif and Waheed [57] studied the nature of scalar field potential for locally rotationally symmetric (LRS) Bianchi type I (BI) universe model in a general scalar-tensor theory via reconstruction technique and they concluded that the reconstructed F o r R e v i e w O n l y potentials are viable on cosmological grounds. In a recent paper [58], we have discussed cosmological reconstruction and energy bounds in a new general f (R, R αβ R αβ , ϕ) gravity. In this gravity, we have also studied the first and second laws of black hole thermodynamics for both equilibrium and non-equilibrium descriptions [59].…”