(An)Isotropic models in scalar and scalar-tensor cosmologies

We study how the constants G and Λ may vary in different theoretical models (general relativity with a perfect fluid, scalar cosmological models (“quintessence”) with and without interacting scalar and matter fields and a scalar-tensor model with a dynamical Λ) in order to explain some observational...

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Bibliographic Details
Published in:	Astrophysics and space science 2012-04, Vol.338 (2), p.381-400
Main Author:	Belinchon, Jose Antonio
Format:	Article
Language:	eng
Subjects:	Anisotropy Astrobiology Astronomy Astrophysics Astrophysics and Astroparticles Computational fluid dynamics Constants Cosmological constant Cosmology Mathematical models Observations and Techniques Original Article Physics Physics and Astronomy Relativity Scalars Space Exploration and Astronautics Space Sciences (including Extraterrestrial Physics Time functions
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Summary:	We study how the constants G and Λ may vary in different theoretical models (general relativity with a perfect fluid, scalar cosmological models (“quintessence”) with and without interacting scalar and matter fields and a scalar-tensor model with a dynamical Λ) in order to explain some observational results. We apply the program outlined in section II to study three different geometries which generalize the FRW ones, which are Bianchi V, VII 0 and IX, under the self-similarity hypothesis. We put special emphasis on calculating exact power-law solutions which allow us to compare the different models. In all the studied cases we arrive at the conclusion that the solutions are isotropic and noninflationary while the cosmological constant behaves as a positive decreasing time function (in agreement with the current observations) and the gravitational constant behaves as a growing time function.
ISSN:	0004-640X 1572-946X