Spatially homogeneous models

Author(s):  
H. O. Georgii
2020 ◽  
Vol 17 (12) ◽  
pp. 2050184
Author(s):  
Evgeny Osetrin ◽  
Konstantin Osetrin ◽  
Altair Filippov ◽  
Ilya Kirnos

All classes of spatially homogeneous spacetime models in the generalized scalar–tensor theory of gravitation are found to allow the integration of the equations of motion of test particles and the eikonal equation by the method of separation of variables by type (3.1). Three classes of exact solutions are obtained that relate to Shapovalov wave-like spacetime models. The resulting spacetime models are of types IV, VI and VII according to the Bianchi classification and type N according to Petrov classification.


2020 ◽  
Vol 63 (3) ◽  
pp. 410-419 ◽  
Author(s):  
E. K. Osetrin ◽  
K. E. Osetrin ◽  
A. E. Filippov

1989 ◽  
Vol 54 (11) ◽  
pp. 2933-2950
Author(s):  
Emerich Erdös ◽  
Petr Voňka ◽  
Josef Stejskal ◽  
Přemysl Klíma

This paper represents a continuation and ending of the kinetic study of the gallium arsenide formation, where a so-called inhomogeneous model is proposed and quantitatively formulated in five variants, in which two kinds of active centres appear. This model is compared both with the experimental data and with the previous sequence of homogeneous models.


Universe ◽  
2020 ◽  
Vol 6 (6) ◽  
pp. 71 ◽  
Author(s):  
Valerio Faraoni

Several classic one-dimensional problems of variational calculus originating in non-relativistic particle mechanics have solutions that are analogues of spatially homogeneous and isotropic universes. They are ruled by an equation which is formally a Friedmann equation for a suitable cosmic fluid. These problems are revisited and their cosmic analogues are pointed out. Some correspond to the main solutions of cosmology, while others are analogous to exotic cosmologies with phantom fluids and finite future singularities.


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