V cosmological models in f(R,T) modified gravity with Λ(T) by using generation technique

Abstract

A new class of cosmological models in f (R, T ) modified theories of gravity proposed by Harko et al. (2011), has been investigated for a specific choice of f (R, T ) = f1(R) + f2(T ) by considering time dependent deceleration parameter. The concept of time dependent deceleration parameter (DP) with some proper assumptions yield the average scale factor a(t) = sinh 1 n (αt), where n and α are positive constants. For 0 < n ≤ 1, this generates a class of accelerating models while for n > 1, the models of universe exhibit phase transition from early decelerating phase to present accelerating phase which is in good agreement with the results from recent astrophysical observations. Our intention is to reconstruct f (R, T ) models inspired by this special law for the deceleration parameter in connection with the theories of modified gravity. In the present study we consider the cosmological constant Λ as a function of the trace of the stress energymomentum-tensor, and dub such a model "Λ(T ) gravity" where we have specified a certain form of Λ(T ). Such models may display better uniformity with the cosmological observations. The statefinder diagnostic pair {r, s} parameter has been embraced to characterize different phases of the universe. We also discuss the physical consequences of the derived models.

Stability of LRS Bianchi type-I cosmological models in f(R, T)-gravity

“…There are many researchers who have thought about cosmology in this theory of gravity. It is not conceivable to say every one of them has yet been considered; we give some pertinent and most recent references which are specifically identified with our present work (Adhav 2012;Shamir 2014;Chaubey & Shukla 2013;Chandel & Ram 2013;Velten & Caramês 2017;Chakraborty 2013;Moraes 2015;Singh et al 2016;Sahu et al 2017;Sahoo et al 2017;Ahmed & Pradhan 2014;Pradhan et al 2015;Mishra et al 2016;Ahmed et al 2016;Tiwari et al 2017;Pradhan & Jaiswal 2018;Sahoo et al 2018;Nagpal et al 2018;Pullen & Kamionkowski 2007;Samal et al 2008 and references therein).…”

Scalar Field Models of Barrow Holographic Dark Energy in f(R,T) Gravity

“…Different hypothetical models can be obtained for different choices of f in the field equations of f (R, T) gravity due to their dependence on the underlying physical nature of the matter field. Various researchers presented the cosmological consequences of the special class f (R, T) = R + 2 f (T) [93][94][95][96][97][98][99].…”

Cosmographic analysis of a closed bouncing universe with the varying cosmological constant in $f(R,T)$ gravity

“…The classical linear energy conditions (ECs) [102] ( the null ρ + p ≥ 0; weak ρ ≥ 0, ρ + p ≥ 0; strong ρ+3p ≥ 0 and dominant ρ ≥ |p| energy conditions ) need to be replaced by other nonlinear ECs [76][77][78] when semiclassical effects are considered [103]. In addition to the classical ones, we will also consider the following three nonlinear ECs:…”