scholarly journals Bianchi type V universe with bulk viscous matter and time varying gravitational and cosmological constants

2012 ◽  
Vol 12 (11) ◽  
pp. 1457-1466 ◽  
Author(s):  
Prashant Singh Baghel ◽  
Jagdish Prasad Singh
Keyword(s):  
Bianchi Type ◽  
Time Varying ◽  
Gravitational And Cosmological Constants ◽  
Bulk Viscous ◽  
Bianchi Type V Universe ◽  
Type V ◽  
Cosmological Constants ◽  
Bianchi Type V

scholarly journals Bianchi Type-V Bulk Viscous Cosmic String inf(R,T)Gravity with Time Varying Deceleration Parameter

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Bïnaya K. Bishi ◽  
K. L. Mahanta
Keyword(s):  
Deceleration Parameter ◽  
Bianchi Type ◽  
Cosmic Strings ◽  
The Other ◽  
Time Varying ◽  
Constant Deceleration Parameter ◽  
Linearly Varying Deceleration Parameter ◽  
Bulk Viscous ◽  
Type V ◽  
Bianchi Type V

We study the Bianchi type-V string cosmological model with bulk viscosity inf(R,T)theory of gravity by considering a special form and linearly varying deceleration parameter. This is an extension of the earlier work of Naidu et al., 2013, where they have constructed the model by considering a constant deceleration parameter. Here we find that the cosmic strings do not survive in both models. In addition we study some physical and kinematical properties of both models. We observe that in one of our models these properties are identical to the model obtained by Naidu et al., 2013, and in the other model the behavior of these parameters is different.

scholarly journals A Generalized Solution of Bianchi Type-V Models with Time-Dependent G and Λ

Universe ◽  
2018 ◽  
Vol 4 (8) ◽  
pp. 83 ◽  
Author(s):  
Alnadhief Alfedeel ◽  
Amare Abebe ◽  
Hussam Gubara
Keyword(s):  
General Solution ◽  
Hypergeometric Function ◽  
Bianchi Type ◽  
Generalized Solution ◽  
Time Dependent ◽  
Field Equations ◽  
Gravitational And Cosmological Constants ◽  
Type V ◽  
Cosmological Constants ◽  
Bianchi Type V

We study the homogeneous but anisotropic Bianchi type-V cosmological model with time-dependent gravitational and cosmological “constants”. Exact solutions of the Einstein field equations (EFEs) are presented in terms of adjustable parameters of quantum field theory in a spatially curved and expanding background. It has been found that the general solution of the average scale factor a as a function of time involved the hypergeometric function. Two cosmological models are obtained from the general solution of the hypergeometric function and the Emden–Fowler equation. The analysis of the models shows that, for a particular choice of parameters in our first model, the cosmological “constant” decreases whereas the Newtonian gravitational “constant” increases with time, and for another choice of parameters, the opposite behaviour is observed. The models become isotropic at late times for all parameter choices of the first model. In the second model of the general solution, both the cosmological and gravitational “constants” decrease while the model becomes more anisotropic over time. The exact dynamical and kinematical quantities have been calculated analytically for each model.

Bianchi type-V solutions with varying G and Λ: The general case

2020 ◽  
Vol 17 (06) ◽  
pp. 2050076
Author(s):  
Alnadhief H. A. Alfedeel ◽  
Amare Abebe
Keyword(s):  
Bianchi Type ◽  
Einstein Field Equations ◽  
Field Equations ◽  
Energy Models ◽  
Runge Kutta Method ◽  
Gravitational And Cosmological Constants ◽  
Phantom Dark Energy ◽  
Type V ◽  
Cosmological Constants ◽  
Bianchi Type V

The homogeneous and anisotropic Bianchi type-V cosmological model with variable gravitational and cosmological “constants” with a general (nonstiff) perfect fluid is investigated. The Einstein field equations (EFEs) are numerically integrated with the fourth-order Runge–Kutta method for different values of [Formula: see text] and [Formula: see text] parameters of quantum fields in a curved and expanding background. Three realistic models, namely matter, radiation and phantom dark energy models are also discussed. In all these models, it was found that the cosmological “constant” decreases with time, whereas the gravitational “constant” increases over time. It is shown that the universe in these models becomes isotropic at late times.

Higher-dimensional energy–momentum problem for Bianchi types V and I universes in gravitation theories

2015 ◽  
Vol 12 (04) ◽  
pp. 1550045 ◽  
Author(s):  
Güliz Kiy ◽  
Sezgin Aygün
Keyword(s):  
Bianchi Type ◽  
Teleparallel Gravity ◽  
Type I ◽  
Four Dimensions ◽  
Momentum Distributions ◽  
Energy And Momentum ◽  
Bianchi Type V Universe ◽  
Energy And Momentum Densities ◽  
Type V ◽  
Bianchi Type V

Using the Einstein, Bergmann–Thomson, Landau–Lifshitz, Møller, Papapetrou and Tolman energy–momentum complexes in general relativity (GR) and teleparallel gravity (TG), we calculate the total energy–momentum distributions associated with N-dimensional Bianchi type V universe. While the solutions of Einstein, Bergmann–Thomson and Tolman energy and momentum densities are the same as each other, the solutions of Landau–Lifshitz, Møller and Papapetrou energy–momentum densities are different for N-dimensional Bianchi type V space-time in GR and TG. Obtained results for Einstein, Bergmann–Thomson and Landau–Lifshitz definitions we could say that GR and TG are in the same class. Because different energy–momentum distributions provide same results. However we have discussed N-dimensional Bianchi type I solutions and then we obtained all energy–momentum solutions are vanish in GR and TG theories. These results agree with Banerjee–Sen, Xulu, Aydoḡdu–Saltı and Radinschi in four dimensions.

scholarly journals Causal heat flow in Bianchi type-V Universe

2014 ◽  
Vol 29 (13) ◽  
pp. 1450071
Author(s):  
M. Govender ◽  
S. Thirukkanesh
Keyword(s):  
Temperature Profile ◽  
Bianchi Type ◽  
Irreversible Thermodynamics ◽  
Hydrostatic Equilibrium ◽  
Rotationally Symmetric ◽  
Spatially Homogeneous ◽  
Bianchi Type V Universe ◽  
Type V ◽  
Bianchi Type V

In this paper, we investigate the role of causal heat transport in a spatially homogeneous, locally-rotationally symmetric (LRS) Bianchi type-V cosmological model. In particular, the causal temperature profile of the cosmological fluid is obtained within the framework of extended irreversible thermodynamics. We demonstrate that relaxational effects can alter the temperature profile when the cosmological fluid is out of hydrostatic equilibrium.

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