Role of deceleration parameter and interacting dark energy in singularity avoidance

Abstract

A class of non-singular bouncing FRW models are obtained by constraining the deceleration parameter in the presence of an interacting dark energy represented by a time-varying cosmological constant. The models being geometrically closed, initially accelerate for a certain period of time and decelerate thereafter and are also free from the entropy and cosmological constant problems. Taking a constant of integration equal to zero one particular model is discussed in some detail and the variation of different cosmological parameters are shown graphically for specific values of the parameters of the model. For some specific choice of the parameters of the model the ever expanding models of Ozer & Taha and Abdel-Rahman and the decelerating models of Berman and also the Einstein de-Sitter model may be obtained as special cases of this particular model.

Reconstruction of cosmic history from a simple parametrization of H

“…For a complete set of decay laws of Λ one can see [78]. q = m − 1 [72], [129] q(t) = −αt + m − 1 [75] q(t) = − α t 2 +β − 1 [74] q(a) = −1− αa α 1+a α [130] q(z) = q 0 +q 1 z [131], [132], [133], [134] q(z) = q 0 +q 1 z(1 + z) −1 [134], [135], [136] q(z) = q 0 +q 1 z(1 + z)(1 + z 2 ) −1 [137] q(z) = 1 2 +q 1 (1 + z) −2 [134] q(z) = q 0 +q 1 [1+ ln (1 + z)] −1 [136] q(z) = 1 2 +(q 1 z + q 2 )(1 + z) −2 [138], [140], [139] q(z) = −1+ 3 2 (1+z) q 2 q 1 +(1+z) q 2 [141] q(z) = − 1 4 3q 1 + 1 − 3(q 1 + 1) q 1 e q 2 (1+z) −e −q 2 (1+z) q 1 e q 2 (1+z) +e −q 2 (1+z) [142] q(z) = − 1 4 + 3 4…”

“…In [73] (with β = 1) and its generalized model [74] are obtained here. Model-XI imitate the linearly varying deceleration parameter model (LVDPt) of Akarsu [75] (where 2 β = −k and α β = m).…”

Bianchi types I and V bulk viscous fluid cosmological models in f(R, T) gravity theory

“…(28) into Eq. (29) and integrating the result, Abdussattar and Prajapati [53] derived three different forms of a(t), the simplest form among them is given by ( ) = They have also discussed the non-singular bouncing FRW cosmological models with a(t) give by Eq. (30).…”

Cosmological models filled with a perfect fluid source in the f(R,T) theory of gravity

“…The present work is studied in the framework the f (R, T ) theory of gravity proposed by Hrko et al (2011) in which R and T are the Ricci scalar and trace of the stress energy tensor, respectively, which is different from the f (R, T ) theory used by Myrzakulov [32] in which R is curvature scalar and T is torsion scalar. In the present paper we investigated the LRS Bianchi type I cosmological model used by Abdussattar et al [20] by assuming the spatial law of variation of Hubble's parameter proposed by Berman [33] and Pawar et al [34,35]. We obtained some physical parameters and discussed their physical behaviors.…”

“…Reddy et al [18,19] investigated the higher dimensional Kaluza-Klein cosmological models as well as Bianchi type III cosmological models in the f (R, T ) theory of gravity. A new class of cosmological models using the special form of the average scale factor is derived by Abdussattar and Prajapati, and Pawar et al [20,21]. Dark energy and dark energy models in the f (R, T ) theory of gravity have recently become an interesting subject of investigation for several authors [22][23][24][25][26][27][28][29][30][31]).…”