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metadata.dc.type: | Artigo de Periódico |
Title: | The cosmic coincidence in Brans–Dicke cosmologies |
Other Titles: | International Journal of Modern Physics D |
Authors: | Carneiro, Saulo |
metadata.dc.creator: | Carneiro, Saulo |
Abstract: | Among the suggested solutions to the cosmological constant problem, we nd the idea of a dynamic vacuum, with an energy density decaying with the universe expansion. We investigate the possibility of a variation in the gravitational constant as well, induced,at the cosmological scale, by the vacuum decay. We consider an e ective Brans{Dicke theory in the spatially at FLRW spacetime, nding late time solutions characterized by a constant ratio between the matter and vacuum energy densities. By using the observed limits for the universe age, we x the only free parameter of our solutions, obtaining a relative matter density in the range 0:25 < m < 0:4. In particular, for Ht = 1 we obtain m = 1=3. This constitutes a possible explanation for another problem related to the cosmological term, the cosmic coincidence problem. |
Keywords: | Cosmological constant Scalar-tensor theories |
metadata.dc.rights: | Acesso Aberto |
URI: | http://repositorio.ufba.br/ri/handle/ri/13357 |
Issue Date: | 2005 |
Appears in Collections: | Artigo Publicado em Periódico (FIS) |
Files in This Item:
File | Description | Size | Format | |
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SAULO CARNEIRO.pdf | 180,72 kB | Adobe PDF | View/Open |
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