scholarly journals A Cosmological Model of the Early Universe Based on ECG with Variable Λ-Term in Lyra Geometry

2015 ◽  
Vol 55 (5) ◽  
pp. 2364-2375 ◽  
Author(s):  
H. Saadat
Keyword(s):  
Cosmological Model ◽  
Early Universe ◽  
Lyra Geometry ◽  
Variable Λ

scholarly journals Cosmological Model with Hybrid Expansion Law in Lyra Geometry

2021 ◽  
Vol 8 (4) ◽  
pp. 82-87
Author(s):  
  D.R. Manekar ◽  
S. R. Bhoyar ◽  
Hemant Kumar
Keyword(s):  
Cosmological Model ◽  
Lyra Geometry

scholarly journals INHOMOGENEOUS COSMOLOGICAL MODEL IN LYRA GEOMETRY

2002 ◽  
Vol 11 (09) ◽  
pp. 1501-1504 ◽  
Author(s):  
F. RAHAMAN ◽  
S. CHAKRABORTY ◽  
J. BERA
Keyword(s):  
Cosmological Model ◽  
Exact Solutions ◽  
Lyra Geometry ◽  
Inhomogeneous Cosmological Model ◽  
Normal Gauge ◽  
Lyra’S Geometry

Exact solutions are obtained for an inhomogeneous cosmological model in normal gauge for Lyra's geometry. Some properties of the model have also been discussed.

scholarly journals Inflationary universe models and clustering of quasar red shifts

1986 ◽  
Vol 119 ◽  
pp. 509-510
Author(s):  
C. Sivaram
Keyword(s):  
Cosmological Model ◽  
Early Universe ◽  
Hubble Constant ◽  
Matter Density ◽  
Inflationary Universe ◽  
Expansion Phase ◽  
Exponential Expansion ◽  
The Universe ◽  
Inflationary Models ◽  
Universe Models

Recently it has been shown that many of the puzzling features of conventional cosmological models (such as the horizon and flatness problems) could be explained by invoking inflationary models of the early universe with an exponential expansion phase at very early epochs. These models have the added advantage that they are able to make a definite prediction about the present matter density in the universe, i.e. they require that the density be exactly equal to the closure density which in turn can be easily estimated from the Hubble constant now known to within a factor of two. Now if one goes back to an earlier idea that explored the possibility of unusual clustering of quasar redshifts around z = 2 or 3, we get an example of another cosmological model with a definite prediction for the present overall matter density. This is a modified version of the Eddington-Lemaitre type of model which naturally accommodates such features as a clustering of quasars at certain epochs. From these models one can get a prediction for the present matter density which would be an involved function of the Hubble constant and the redshifts at which such clustering occurs. It can be shown that if such clustering had occurred at any z, the present matter density predicted would be substantially smaller than the corresponding closure density. The conclusion is that any clustering of quasar redshifts is incompatiable with inflationary universe models, indirectly providing observational support for these new theories.

scholarly journals PLANE-SYMMETRIC INHOMOGENEOUS BULK VISCOUS COSMOLOGICAL MODELS WITH VARIABLE Λ

2003 ◽  
Vol 12 (05) ◽  
pp. 941-951 ◽  
Author(s):  
ANIRUDH PRADHAN ◽  
HARE RAM PANDEY
Keyword(s):  
Cosmological Model ◽  
Viscous Fluid ◽  
Cosmological Constant ◽  
Ad Hoc ◽  
Fluid Distribution ◽  
Geometric Features ◽  
Plane Symmetric ◽  
Bulk Viscous Fluid ◽  
Variable Λ ◽  
Bulk Viscous

A plane-symmetric non-static cosmological model representing a bulk viscous fluid distribution has been obtained which is inhomogeneous and anisotropic and a particular case of which is gravitationally radiative. Without assuming any ad hoc law, we obtain a cosmological constant as a decreasing function of time. The physical and geometric features of the models are also discussed.

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.

Bianchi type VI cosmological model with electromagnetic field in Lyra geometry

2016 ◽  
Vol 94 (10) ◽  
pp. 992-1000 ◽  
Author(s):  
M. Abdel-Megied ◽  
E.A. Hegazy
Keyword(s):  
Electromagnetic Field ◽  
Cosmological Model ◽  
Bianchi Type ◽  
Lyra Geometry ◽  
Geometrical Properties ◽  
Special Cases ◽  
Type V ◽  
Tensor Formula ◽  
Shear Tensor ◽  
Bianchi Type V

Bianchi type VI cosmological model in the presence of electromagnetic field with variable magnetic permeability in the framework of Lyra geometry is presented. An exact solution is introduced by considering that the eigenvalue [Formula: see text] of the shear tensor [Formula: see text] is proportional to the scalar expansion Θ of the model, that is, C = (AB)L, where A, B, and C are the coefficients of the metric and L is a constant. Bianchi type V, III, and I cosmological models are given as special cases of Bianchi type VI. Physical and geometrical properties of the models are discussed.

Kaluza-Klein Tilted Cosmological Model in Lyra Geometry

2017 ◽  
Vol 42 (3) ◽  
pp. 1451-1457 ◽  
Author(s):  
Subrata Kumar Sahu ◽  
Samuel Ganiamo Ganebo ◽  
Gebretsadik Gidey Weldemariam
Keyword(s):  
Cosmological Model ◽  
Lyra Geometry ◽  
Tilted Cosmological Model ◽  
Kaluza Klein

HIGHER DIMENSIONAL COSMOLOGICAL MODEL IN LYRA GEOMETRY: REVISITED

2003 ◽  
Vol 12 (05) ◽  
pp. 853-860 ◽  
Author(s):  
G. P. SINGH ◽  
S. KOTAMBKAR ◽  
ANIRUDH PRADHAN
Keyword(s):  
Cosmological Model ◽  
Power Law ◽  
Bulk Viscosity ◽  
Research Work ◽  
Lyra Geometry ◽  
Universe Model ◽  
Higher Dimensional ◽  
Empty Universe ◽  
Kaluza Klein

In this paper we have revisited the research work of Rahman and Bera22on Kaluza–Klein cosmological model within the framework of Lyra Geometry. It has been shown that the empty universe model yields a power law relation without any assumption. The role of bulk viscosity on five-dimensional cosmological model is discussed. The physical behaviour of the models is examined in all cases.

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