Friedmann cosmological models with bulk viscosity in a scale covariant theory

2007 ◽  
Vol 310 (3-4) ◽  
pp. 269-271 ◽  
Author(s):  
N. Ibotombi Singh ◽  
Anita Sorokhaibam
Keyword(s):  
Bulk Viscosity ◽  
Cosmological Models ◽  
Covariant Theory ◽  
Scale Covariant Theory ◽  
Friedmann Cosmological Models

Scale-covariant theory of gravitation and astrophysical applications

1977 ◽  
Vol 16 (6) ◽  
pp. 1643-1663 ◽  
Author(s):  
V. Canuto ◽  
P. J. Adams ◽  
S.-H. Hsieh ◽  
E. Tsiang
Keyword(s):  
Covariant Theory ◽  
Scale Covariant Theory ◽  
Theory Of Gravitation

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.

scholarly journals Some Friedmann cosmological solutions in the scale covariant theory of gravitation

1991 ◽  
Vol 14 (2) ◽  
pp. 305-308 ◽  
Author(s):  
Aroonkumar Beesham
Keyword(s):  
Gravitational Constant ◽  
Gauge Function ◽  
Covariant Theory ◽  
Time Varying ◽  
Scale Covariant Theory ◽  
Independent Equation ◽  
Cosmological Solutions ◽  
Theory Of Gravitation ◽  
Varying Gravitational Constant ◽  
Friedmann Robertson Walker

The scale covariant theory of gravity admits the possibility of a time varying gravitational constant but contains a gauge function for which there is no independent equation. The circumstances under which explicit forms for a gauge function may be derived within the context of Friedmann-Robertson-Walker cosmological models are investigated and several forms are derived.

scholarly journals Isotropization of Homogeneous Cosmological Models

1974 ◽  
Vol 63 ◽  
pp. 273-282
Author(s):  
I. D. Novikov
Keyword(s):  
Large Scale ◽  
Background Radiation ◽  
Cosmological Models ◽  
Matter Distribution ◽  
Cosmological Singularity ◽  
Universe Expand ◽  
Starting Point ◽  
Microwave Background Radiation ◽  
Friedmann Cosmological Models ◽  
The Universe

Observations primarily of the microwave background radiation show that the Universe expands isotropically with a high degree of accuracy at the present time and that the matter distribution is homogeneous on a large scale. Thus, the Friedmann cosmological models are a good approximation today for the expanding Universe. This is valid for at least some period of time in the past too. But how did the Universe expand and what was the matter distribution close to the starting point, near the cosmological singularity?

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