Bulk viscous Bianchi type I cosmological model in Lyra geometry and in the general theory of relativity

2020 ◽  
Vol 365 (7) ◽  
Author(s):  
E. A. Hegazy
Keyword(s):  
General Theory ◽  
Cosmological Model ◽  
Bianchi Type ◽  
Lyra Geometry ◽  
Type I ◽  
Theory Of Relativity ◽  
General Theory Of Relativity ◽  
Bianchi Type I ◽  
Bulk Viscous

Homothetic vector fields in a specially homogenous Bianchi type-I cosmological model in Lyra geometry

2015 ◽  
Vol 93 (11) ◽  
pp. 1397-1401 ◽  
Author(s):  
A.S. Alofi ◽  
Ragab M. Gad
Keyword(s):  
Cosmological Model ◽  
Riemannian Geometry ◽  
Vector Fields ◽  
Bianchi Type ◽  
Displacement Vector ◽  
Lyra Geometry ◽  
Type I ◽  
Bianchi Type I ◽  
Homothetic Vector ◽  
Vector Formula

In this paper, homothetic vector fields of a spatially homogenous Bianchi type-I cosmological model have been evaluated based on Lyra geometry. Further, we investigate the equation of state in cases when a displacement vector [Formula: see text] is a function of t and when it is constant. We give a comparison between the obtained results, using Lyra geometry, and those obtained previously in the context of general relativity, based on Riemannian geometry.

BULK VISCOUS BIANCHI TYPE I BAROTROPIC FLUID COSMOLOGICAL MODEL WITH VARYING Λ AND FUNCTIONAL RELATION ON HUBBLE PARAMETER IN ROSEN’S BIMETRIC GRAVITY

2021 ◽  
Vol 10 (5) ◽  
pp. 2515-2525
Author(s):  
N.P. Gaikwad ◽  
P.V. Lepse ◽  
B.K. Bishi ◽  
N.K. Ashtankar
Keyword(s):  
Cosmological Model ◽  
Hubble Parameter ◽  
Bianchi Type ◽  
Functional Relation ◽  
Late Time ◽  
Type I ◽  
Bianchi Type I ◽  
Barotropic Fluid ◽  
Bimetric Gravity ◽  
Bulk Viscous

We have deduced that bulk viscous Bianchi type I barotropic fluid cosmological model with varying $\Lambda$ and functional relation on hubble parameter by solving the field equations bimetric theory of gravitation. It is observed that our model has exponentially accelerating expansion at late time starting with decelerating expansion which agreed the observation of Perlmutter (1998), Knop (2003), Tegmark (2004) and Spergel (2006). In the beginning, our model has more than three spatial-dimensions then it switched over to three-dimensional spatial geometry at late epoch of time and it is agreed with Borkar et al. (2013). Other geometrical and physical behavior of the model have been studied.

Bianchi type-I bulk viscous cosmology with Chaplygin gas in Lyra Geometry

2016 ◽  
Vol 54 (6) ◽  
pp. 895-905 ◽  
Author(s):  
G.P. Singh ◽  
Binaya K. Bishi ◽  
P.K. Sahoo
Keyword(s):  
Bianchi Type ◽  
Lyra Geometry ◽  
Chaplygin Gas ◽  
Type I ◽  
Bianchi Type I ◽  
Viscous Cosmology ◽  
Bulk Viscous
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