Cosmological models in alternative theory of gravity with bilinear deceleration parameter

Mishra, R. K.; Chand, Avtar

doi:10.1007/s10509-016-2837-6

Cited by 34 publications

(26 citation statements)

References 24 publications

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“…Our previous work [60] deals with the linearly varying DP and the result is compatible with recent observations. Here, we have considered a bilinear DP [61] in two forms i.e (i) q = α(1−t) 1+t and (ii) q = −αt 1+t and a time varying DP [62] i.e q = −1 + β 1+a β .…”

Section: Solutions Of Field Equationsmentioning

confidence: 99%

Magnetized strange quark matter in f ( R, T ) gravity with bilinear and special form of time varying deceleration parameter

2018

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In this paper, we have studied homogeneous and anisotropic locally rotationally symmetric (LRS) Bianchi type-I model with magnetized strange quark matter (MSQM) distribution and cosmological constant Λ in f (R, T ) gravity where R is the Ricci scalar and T the trace of matter source. The exact solutions of the field equations are obtained under bilinear and special form of time varying deceleration parameter (DP). Firstly, we have considered two specific forms of bilinear DP with a single parameter of the form: q = α(1−t) 1+t and q = − αt 1+t , which leads to the constant or linear nature of the function based on the constant α. Second one is the special form of the DP as q = −1 + β 1+a β . From the results obtained here, one can observe that in the early universe magnetic flux has more effects and it reduces gradually in the later stage. For t → ∞, we get p → −Bc and ρ → Bc. The behaviour of strange quark matter along with magnetic epoch gives an idea of accelerated expansion of the universe as per the observations of the type Ia Supernovae.The theoretical arguments for the late-time cosmic acceleration are being a major issue among cosmologist of the twentieth century. The idea of this accelerated expansion of universe was discovered nearly 20 years ago by observations through Supernovae Ia [1-5], CMB [6,7], baryon acoustic oscillation (BAO) in galaxy clustering [8][9][10] and WMAP [11] etc. To investigate the nature of the universe, modern cosmology continues to test the above predictions, which leads to the refinement of cosmological models. The nature and behaviour of some unknown mechanism of the universe are responsible for this accelerated expansion, commonly referred as dark energy and contains more energy budget of the universe along with negative pressure. It triggers one of the important issue to study the current acceleration of the universe.Instead of resorting the mysterious concept of dark energy, there is an alternative way to reproduce the dynamics of the expanding universe through modified theories of gravity which is an extension of general relativity. These modifications can occur in several ways such as: one can use a base as the torsional formulation of general relativity called the teleparallel gravity equivalent to general relativity [12] e.g. f (T ) gravity, where T is the torsion scalar. On the other hand one can start the curvature formulation of general relativity in Einstein-Hilbert action by replacing the Ricci scalar with its arbitrary functions or even more complicated curvature invariants such as: f (R), f (R, G) gravity, and the latest f (R, T ) gravity proposed by Harko et al. [13]. The matter Lagrangian of f (R, T ) gravity coupled with Ricci scalar R and trace of energy-momentum tensor T . Such Lagrangian with matter content will differ from the Einstein's one. It has much significance to study late-time cosmic acceleration as well as dark energy and dark matter problem [14][15][16][17]. Hypothetically matter plays more fundamental role in the description of gravitational eff...

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Section: Solutions Of Field Equationsmentioning

confidence: 99%

Magnetized strange quark matter in f ( R, T ) gravity with bilinear and special form of time varying deceleration parameter

2018

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“…as the second physically plausible relation. Where α 2 , α 3 ∈ R. The considered form of deceleration parameter is motivated by the bilinear form of deceleration parameter [32]. Deceleration parameter is useful to classify the models of the Universe.…”

Section: Field Equationsmentioning

confidence: 99%

“…Accelerating respectively, which is discussed by [32]. They called this deceleration parameter as Bilinear variable deceleration parameter.…”

Section: Field Equationsmentioning

confidence: 99%

“…Now we will discuss about the deceleration parameter in serial numbers 2, 5, 8 and 9 of Table 1. For the choice of α 2 = α = α 4 , the deceleration parameter q in serial number 2 and 5 of Table 1 reduces to q = − αt 1+t and q = −α(1+t) 1+t respectively, which is discussed by [32]. They called this deceleration parameter as Bilinear variable deceleration parameter.…”

Section: Form Of Deceleration Parameter Qmentioning

confidence: 99%

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Bulk Viscous Cosmological Model in Brans-Dicke Theory with New Form of Time Varying Deceleration Parameter

Singh

Bishi

2017

Advances in High Energy Physics

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“…as studied and published by our peer research group [25][26][27][28] , we may also believed that time dependence of the scale factor a(t), reflect mainly in expansion rate of the universe. So under this motivation we have decided to find an exact solution of EFEs along with study of various others associated aspect with time varying DP.…”

Section: Solution Of the Field Equationsmentioning

confidence: 99%

Bianchi type-III String Cosmological Models in Brans-Dicke Theory of Gravity

Mishra¹,

Chand²

2019

jusps-A

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A Bianchi type-III string cosmological models is investigated in scalar-tensor Brans-Dicke theory of gravity (Phys. Rev. 124, 925, 1961). For an exact solution of modified Einstein 's field equations (EFEs), we assumed time varying nature of deceleration parameter (DP) along with relation between scale factor and time, given by a(t)=[t  e t )] n 1 ,  and n are non-negative constants. It is noticed from study that the power index has their own significance on the string cosmological models. It is also analyzed that the string tension density () is an increasing function of time whereas the energy density () and the cosmological constant () are decreasing functions of time and converges to small value at present time.

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Cosmological models in alternative theory of gravity with bilinear deceleration parameter

Cited by 34 publications

References 24 publications

Magnetized strange quark matter in f ( R, T ) gravity with bilinear and special form of time varying deceleration parameter

Magnetized strange quark matter in f ( R, T ) gravity with bilinear and special form of time varying deceleration parameter

Bulk Viscous Cosmological Model in Brans-Dicke Theory with New Form of Time Varying Deceleration Parameter

Bianchi type-III String Cosmological Models in Brans-Dicke Theory of Gravity

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