NEW BIANCHI I MODEL

1991 ◽  
Vol 06 (01) ◽  
pp. 97-101 ◽  
Author(s):  
JOSEPH HAJJ-BOUTROS
Keyword(s):  
Bianchi Type ◽  
State Equation ◽  
Initial Singularity ◽  
Type I ◽  
Bianchi Type I ◽  
Bianchi I

We deal with a state equation depending on the cosimic time t, i.e. μ=f(t)p. The metric is of L.R. S. Bianchi type I. The obtained solution describes the initial singularity where radiation dominates and evolves into the matter-dominated regime with increasing time.

scholarly journals BIANCHI TYPE I UNIVERSES WITH CAUSAL BULK VISCOUS COSMOLOGICAL FLUID

2002 ◽  
Vol 11 (03) ◽  
pp. 447-462 ◽  
Author(s):  
M. K. MAK ◽  
T. HARKO
Keyword(s):  
Bianchi Type ◽  
Viscosity Coefficient ◽  
State Equation ◽  
Type I ◽  
Bianchi Type I ◽  
Boltzmann Gas ◽  
Bulk Viscous ◽  
Barotropic Equation ◽  
Bulk Viscosity Coefficient ◽  
The Universe

We consider the dynamics of a causal bulk viscous cosmological fluid filled flat constantly decelerating Bianchi type I spacetime. The matter component of the Universe is assumed to satisfy a linear barotropic equation of state and the state equation of the small temperature Boltzmann gas. The resulting cosmological models satisfy the condition of smallness of the viscous stress. The time evolution of the relaxation time, temperature, bulk viscosity coefficient and comoving entropy of the dissipative cosmological fluid is also obtained.

scholarly journals Classical Bianchi Type I Cosmology in K-Essence Theory

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
J. Socorro ◽  
Luis O. Pimentel ◽  
Abraham Espinoza-García
Keyword(s):  
Cosmological Model ◽  
Cosmological Constant ◽  
Exact Solutions ◽  
Bianchi Type ◽  
Friedmann Equation ◽  
Matter Content ◽  
Type I ◽  
Bianchi Type I ◽  
Bianchi I ◽  
The Universe

We use one of the simplest forms of the K-essence theory and we apply it to the classical anisotropic Bianchi type I cosmological model, with a barotropic perfect fluid (p=γρ) modeling the usual matter content and with cosmological constantΛ. Classical exact solutions for anyγ≠1andΛ=0are found in closed form, whereas solutions forΛ≠0are found for particular values in the barotropic parameter. We present the possible isotropization of the cosmological model Bianchi I using the ratio between the anisotropic parameters and the volume of the universe. We also include a qualitative analysis of the analog of the Friedmann equation.

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

2019 ◽  
Vol 19 (4) ◽  
pp. 055 ◽  
Author(s):  
Umesh Kumar Sharma ◽  
Rashid Zia ◽  
Anirudh Pradhan ◽  
Aroon Beesham
Keyword(s):  
Bianchi Type ◽  
Cosmological Models ◽  
Type I ◽  
Bianchi Type I

Energy–momentum distributions of Ruban universe in general relativity and teleparallel gravity

2019 ◽  
Vol 34 (03n04) ◽  
pp. 1950011 ◽  
Author(s):  
C. Aktaş
Keyword(s):  
General Relativity ◽  
Bianchi Type ◽  
Teleparallel Gravity ◽  
Type I ◽  
Universe Model ◽  
Zero Energy ◽  
Bianchi Type I ◽  
Momentum Distributions ◽  
Bianchi Type I Universe

In this study, we obtain Einstein, Bergmann–Thomson (BT), Landau–Lifshitz (LL), Møller, Papapetrou (PP) and Tolman energy–momentum (EM) distributions for Ruban universe model in general relativity (GR) and teleparallel gravity (TG). We obtain same results for Einstein, Bergmann–Thomson and Landau–Lifshitz energy–momentum distributions in GR and TG. Also, we get same results for Einstein and Tolman energy–momentum distributions in GR. The Møller energy–momentum results are different in GR and TG. Also, using Ruban universe model, we obtain LRS Bianchi type I solutions and we get zero energy–momentum results for this universe model in GR and TG. These results of LRS Bianchi type I universe model agree with Aygün et al., Taşer et al., Doğru et al., Banerjee–Sen, Tryon and Xulu in different gravitation theories.

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