Exact Solutions of Brans-Dicke Cosmology and the Cosmic Coincidence Problem
نویسندگان
چکیده
We present some cosmological solutions of Brans-Dicke theory, characterized by a decaying vacuum energy density and by a constant relative matter density. With these features, they shed light on the cosmological constant problems, leading to a presently small vacuum term, and to a constant ratio between the vacuum and matter energy densities. By fixing the only free parameter of our solutions, we obtain cosmological parameters in accordance with observations of the relative matter density, the universe age and redshift-distance relations.
منابع مشابه
p-Branes and Exact solutions in Brans-Dicke cosmology with matter
We study the effect of the solitonic degree of freedom in string cosmology following the line Rama. The gas of solitonic p-brane is treated as a perfect fluid in a Brans-Dicke type theory. In this paper, we find analytic solutions for a few solvable cases of equation of states with general Brans-Dicke parameter ω and study the cosmology of the solutions. In some cases the solutions are free fro...
متن کاملar X iv : g r - qc / 9 90 10 59 v 2 2 4 Ja n 19 99 Phases of the Brans - Dicke Cosmology with Matter
We study the cosmology of the Brans-Dicke theory with perfect fluid type matter. In our previous work, we found exact solutions for any Brans-Dicke parameter ω and for general parameter γ of equation of state. In this paper we further study the cosmology of these solutions by analyzing them according to their asymptotic behaviors. The cosmology is classified into 19 phases according to the valu...
متن کاملکیهانشناسی کلاسیکی برانز- دیکی در چارچوب اینشتین و تغییر نشان متریک
Pauli (or Einstein) frame is used to study the Brans-Dicke gravity theory, minimally coupled with dilatonic Brans-Dicke scalar field, whose solutions involve degenerate metrics. Some of these solutions exhibit transitions from an Euclidean domain to a Lorentzian space-time corresponding to a spatially flat Robertson-Walker cosmology.
متن کامل- qc / 9 90 10 59 v 1 2 2 Ja n 19 99 Phases of the Brans - Dicke Cosmology with Matter
We study the cosmology of the Brans-Dicke theory with perfect fluid type matter. In our previous work [7], we found exact solutions for any BransDicke parameter ω and for general parameter γ of equation of state. In this paper we further study the cosmology of these solutions by analyzing them according to their asymptotic behaviors. The cosmology is classified into 19 phases according to the v...
متن کاملp-Brane cosmology and phases of Brans-Dicke theory with matter
We study the effect of the solitonic degree of freedom in string cosmology following the line of Rama. The gas of solitonic p-brane is treated as a perfect fluid in a Brans-Dicke type theory. In this paper, we find exact cosmological solutions for any Brans-Dicke parameter ω and for general parameter γ of equation of state and classify the the cosmology of the solutions according to the paramet...
متن کامل