Some exact solutions of string cosmology with heat flux in Bianchi type III space-time

1996 ◽  
Vol 245 (1) ◽  
pp. 131-138 ◽  
Author(s):  
Ilhami Yavuz ◽  
Ihsan Yilmaz
Keyword(s):  
Heat Flux ◽  
Exact Solutions ◽  
Bianchi Type ◽  
Space Time ◽  
String Cosmology ◽  
Type Iii

THE DE SITTER UNIVERSE MODELS

1995 ◽  
Vol 04 (01) ◽  
pp. 115-159 ◽  
Author(s):  
E. ERIKSEN ◽  
Ø. GRØN
Keyword(s):  
Bianchi Type ◽  
De Sitter Space ◽  
Space Time ◽  
Analytic Extension ◽  
Coordinate Transformations ◽  
De Sitter ◽  
Type Iii ◽  
Dimensional Spacetime ◽  
De Sitter Universe ◽  
Universe Models

The kinematical properties of the de Sitter space-time are reviewed and investigated. The properties of the static sections are clarified. A deduction of the analytic extension, analogous to that of Kruskal and Szekeres for the Schwarzschild space-time, of the static section to the region outside the horizon is given. The representation of the de Sitter space-time as a four-dimensional hyperboloid in Minkowskian five-dimensional spacetime is reviewed. Coordinate transformations between different sections of the de Sitter space-time are found. By means of the transformation formulae the different sections are mapped onto each other in space-time diagrams. These mappings are interpreted kinematically. We have aimed at providing, whenever possible, an intuitive understanding of the kinematical properties of the different sections, and how they are interrelated. Among others we present real coordinate transformations between the static and the three Robertson-Walker sections of the de Sitter space-time on one hand and the vacuum dominated Bianchi type-III model on the other hand. These transformations are used to map the path of a typical Bianchi type-III reference particle into the static and the Robertson-Walker sections.

scholarly journals Higher Dimensional Bianchi Type-III String Cosmological Models in Lyra Geometry

2021 ◽  
Author(s):  
Kangujam Priyokumar Singh ◽  
Jiten Baro ◽  
Asem Jotin Meitei ◽  
S. Romaleima Devi
Keyword(s):  
Bianchi Type ◽  
Dimensional Space ◽  
Big Bang ◽  
Lyra Geometry ◽  
Space Time ◽  
Cosmological Models ◽  
Model Universe ◽  
Type Iii ◽  
First Case ◽  
Dimensional Space Time

Here we studied Bianchi type-III string cosmological models generated by means of a cloud of strings with particles connected to them in the framework of Lyra geometry considering five-dimensional space-time. To obtain the exact solutions of field equations we consider that the shear scalar and the scalar expansion are proportional, σ∞θ which leads to D=cn and secondly we adopt the assumption considering the Reddy String Condition, ρ+λ=0. From the two different cases obtained here, first case leads to the Bianchi type-III string cosmological model in Lyra geometry in five-dimensional space-time and the second case leads to the five-dimensional vacuum universe in general relativity. The Geometrical and physical properties of the model universe are studied comparing with the present day’s observational findings. The model universe obtained here starts with the big bang and as time progresses both particle density ρp and energy density ρ decreases with expansion of our Universe.

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