Bianchi type VI0 generalized ghost pilgrim dark energy model in Brans–Dicke theory of gravitation

2016 ◽  
Vol 94 (10) ◽  
pp. 1040-1044 ◽  
Author(s):  
V.U.M. Rao ◽  
U.Y. Divya Prasanthi
Keyword(s):  
Dark Energy ◽  
Bianchi Type ◽  
Field Equations ◽  
Pilgrim Dark Energy ◽  
Geometrical Properties ◽  
Scalar Expansion ◽  
Theory Of Gravitation ◽  
Shear Scalar ◽  
Bianchi Type Vi0 ◽  
Average Scale Factor

In this paper, we solve Brans–Dicke (BD) theory (Phys. Rev. D, 24, 925) field equations for anisotropic Bianchi type VI0 space–time and discuss evolution of the expanding Universe. Here, we consider pressureless fluid and isotropic generalized ghost pilgrim dark energy as the source of matter and dark energy, respectively. To get the determinate solution of the field equations we have used (i) scalar expansion proportional to the shear scalar and (ii) scalar field (in BD theory) proportional to average scale factor of the model. Some physical and geometrical properties of the model are also discussed.

scholarly journals Bianchi type-VI0 modified holographic Ricci dark energy model in a scalar–tensor theory

2017 ◽  
Vol 95 (2) ◽  
pp. 179-183 ◽  
Author(s):  
M. Vijaya Santhi ◽  
V.U.M. Rao ◽  
Y. Aditya
Keyword(s):  
Dark Energy ◽  
Bianchi Type ◽  
Scalar Tensor Theory ◽  
Field Equations ◽  
Ricci Dark Energy ◽  
Tensor Theory ◽  
Expansion Scalar ◽  
Shear Scalar ◽  
Average Scale Factor ◽  
Good Agreement

In this paper, we consider Bianchi type-VI0 space–time filled with anisotropic modified holographic Ricci dark energy in a scalar–tensor theory proposed by Brans–Dicke (Phys. Rev. 124, 925 (1961)). The field equations in this scalar–tensor theory, have been solved for the following physically relevant assumptions: (i) the scalar field ([Formula: see text]) is proportional to average scale factor (a(t)), (ii) expansion scalar (θ) in the model is proportional to shear scalar (σ). It has been observed that the presented universe is in an accelerating phase at the present epoch, which is in good agreement with the recent astronomical observations. We have also discussed some other properties of the obtained model.

scholarly journals Bianchi Type-VI0 Cosmological Model with Special Form of Scale Factor in Sen-Dunn Theory of Gravitation

2021 ◽  
Vol 13 (1) ◽  
pp. 137-143
Author(s):  
D. Basumatay ◽  
M. Dewri
Keyword(s):  
Cosmological Model ◽  
Special Form ◽  
Bianchi Type ◽  
Scale Factor ◽  
Type I ◽  
Einstein Field Equations ◽  
Field Equations ◽  
Geometrical Properties ◽  
Theory Of Gravitation ◽  
Bianchi Type Vi0

A Bianchi Type-VI0 cosmological model with a special form of scale factor is studied. Einstein field equations in Sen-Dunn theory are obtained and solved for exact solutions. This solution gives a scenario of the dark energy model which tends to a ɅCDM model. The physical and geometrical properties are also obtained and analyzed with the present day observations.

Bianchi type I cosmological model with perfect fluid and string in f(T) theory of gravitation

2020 ◽  
Vol 29 (08) ◽  
pp. 2050054
Author(s):  
V. R. Chirde ◽  
S. P. Hatkar ◽  
S. D. Katore
Keyword(s):  
Dark Energy ◽  
Perfect Fluid ◽  
Bianchi Type ◽  
Type I ◽  
Field Equations ◽  
Bianchi Type I ◽  
Functional Forms ◽  
Theory Of Gravitation ◽  
Shear Scalar ◽  
The Universe

We have studied LRS Bianchi type I cosmological models with barotropic perfect fluid and cosmic string in the framework of [Formula: see text] theory of gravitation. We have assumed that expansion of the model is proportional to the shear scalar. Hybrid law of expansion is also used to solve the field equations. Three different functional forms of the function [Formula: see text] such as [Formula: see text] [Formula: see text] and [Formula: see text] are chosen for investigation. It is observed that the universe is dominated by quintessence type dark energy. The universe is accelerating, expanding and anisotropic.

scholarly journals Bianchi type-III Tsallis holographic dark energy model in Saez–Ballester theory of gravitation

2020 ◽  
Vol 80 (12) ◽  
Author(s):  
M. Vijaya Santhi ◽  
Y. Sobhanbabu
Keyword(s):  
Dark Energy ◽  
Bianchi Type ◽  
Graphical Representation ◽  
Holographic Dark Energy ◽  
Cosmological Parameters ◽  
State Parameter ◽  
Field Equations ◽  
Om Diagnostic ◽  
Hubble Radius ◽  
Theory Of Gravitation

AbstractIn this paper, we have investigated Tsallis holographic dark energy (infrared cutoff is the Hubble radius) in homogeneous and anisotropic Bianchi type-III Universe within the framework of Saez–Ballester scalar–tensor theory of gravitation. We have constructed non-interaction and interaction dark energy models by solving the Saez–Ballester field equations. To solve the field equations, we assume a relationship between the metric potentials of the model. We developed the various cosmological parameters (namely deceleration parameter q, equation of state parameter $$\omega _t$$ ω t , squared sound speed $$v_s^2$$ v s 2 , om-diagnostic parameter Om(z) and scalar field $$\phi $$ ϕ ) and well-known cosmological planes (namely $$\omega _t-\omega _t^{'}$$ ω t - ω t ′ plane, where $$'$$ ′ denotes derivative with respect to ln(a) and statefinders ($$r-s$$ r - s ) plane) and analyzed their behavior through graphical representation for our both the models. It is also, quite interesting to mention here that the obtained results are coincide with the modern observational data.

Anisotropic Bianchi type-II modified holographic Ricci dark energy model in scale-covariant theory of gravitation

2021 ◽  
Author(s):  
Shri Ram ◽  
S. Chandel ◽  
M.K. Verma
Keyword(s):  
Dark Energy ◽  
Bianchi Type ◽  
Covariant Theory ◽  
Type Ii ◽  
Field Equations ◽  
Ricci Dark Energy ◽  
Scale Covariant Theory ◽  
Cosmological Observations ◽  
Negative Constant ◽  
Theory Of Gravitation

In this paper, we obtain an anisotropic Bianchi type-II space-time with dark matter and the modified holographic Ricci dark energy in the scale-covariant theory of gravitation. Exact solutions of the field equations are obtained by assuming (I) a negative constant value of the deceleration parameter (II) the component σ<sup>1</sup><sub>1</sub> of the shear tensor σ<sup>j</sup><sub>i</sub> is proportional to the mean Hubble parameter and (III) the gauge function Φ is proportional to a power function of the average scale factor. We have also discussed some important physical aspects of the model which is in agreement with the modern cosmological observations.

Magnetized anisotropic dark energy cosmological models in scale covariant theory of gravitation

2014 ◽  
Vol 23 (07) ◽  
pp. 1450065 ◽  
Author(s):  
S. D. Katore ◽  
M. M. Sancheti ◽  
S. P. Hatkar
Keyword(s):  
Dark Energy ◽  
Bianchi Type ◽  
Covariant Theory ◽  
Type Ii ◽  
Field Equations ◽  
Scale Covariant Theory ◽  
Anisotropic Dark Energy ◽  
Expansion Scalar ◽  
Viii And Ix ◽  
Theory Of Gravitation

In the present paper, we have investigated Bianchi type II, VIII and IX spacetime in the presence of magnetized anisotropic dark energy in the Scale covariant theory of gravitation. Exact solution of the field equations are obtained by assuming the expansion anisotropy (the ratio of shear scalar to expansion scalar) to be a function of average scale factor. The isotropy of the fluid, space and expansion are examined.

scholarly journals Bianchi Type- I Bulk Viscosity with a DE Cosmological Model

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Daba Meshesha Gusu
Keyword(s):  
Dark Energy ◽  
Cosmological Model ◽  
Bulk Viscosity ◽  
Bianchi Type ◽  
Early Time ◽  
Observational Result ◽  
Type I ◽  
Field Equations ◽  
Geometrical Properties ◽  
The Universe

The finding article presents Bianchi type- I universe in the presence of bulk viscous and DE fluid nature of a cosmological model. The solutions of field equations were obtained by assuming hybrid expansion law. The physical significance of the obtained findings illustrates the dominance of bulk viscosity in early and dominance of dark energy fluid emergences in late. This leads to indicate the presence of bulk viscosity nature more effective in early time rather than late times, and also, it shows the dominance of dark energy in late times which grants the current observational result of the universe. Certain physical and geometrical properties of the model are also discussed.

scholarly journals Bianchi Type-I Dark Energy Cosmology with Power-Law Relation in Brans-Dicke Theory of Gravitation

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
S. D. Katore ◽  
D. V. Kapse
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Power Law ◽  
Bianchi Type ◽  
Type I ◽  
Field Equations ◽  
Coincidence Problem ◽  
Bianchi Type I ◽  
Interacting Dark Energy ◽  
Theory Of Gravitation

We have studied the interacting and non-interacting dark energy and dark matter in the spatially homogenous and anisotropic Bianchi type-I model in the Brans-Dicke theory of gravitation. The field equations have been solved (i) by using power-law relation and (ii) by assuming scale factor in terms of redshift. Here we have considered two cases of an interacting and non-interacting dark energy scenario and obtained general results. It has been found that for suitable choice of interaction between dark energy and dark matter we can avoid the coincidence problem which appears in the ΛCDM model. Some physical aspects and stability of the models are discussed in detail. The statefinder diagnostic pair, i.e., {r,s}, is adopted to differentiate our dark energy models.

scholarly journals A modified holographic Ricci dark energy model in a self-creation cosmology

2016 ◽  
Vol 94 (12) ◽  
pp. 1314-1318 ◽  
Author(s):  
M.P.V.V. Bhaskara Rao ◽  
D.R.K. Reddy ◽  
K. Sobhan Babu
Keyword(s):  
Dark Energy ◽  
Dark Energy Model ◽  
Bianchi Type ◽  
Energy Model ◽  
Smooth Transition ◽  
Type Ii ◽  
Field Equations ◽  
Ricci Dark Energy ◽  
Theory Of Gravitation ◽  
The Universe

This paper deals with a locally rotationally symmetric Bianchi type II space–time with dark matter and anisotropic modified holographic Ricci dark energy as source in second self-creation theory of gravitation proposed by Barber (Gen. Relativ. Gravit. 14, 117 (1982)). To solve the field equations of this theory we have used (i) hybrid expansion law, (ii) a relation between metric potentials and a modified holographic Ricci dark energy given by Chen and Jing (Phys. Lett. B, 679, 144 (2009)). The solution obtained represents a Bianchi type II modified holographic dark energy model in self-creation cosmology. We observe that there is a smooth transition of the universe from decelerated phase to accelerated phase. This fact is in good agreement with the observations of modern cosmology. We have also discussed some important physical aspects of the model.

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