Exact solutions of Brans-Dicke cosmology with decaying vacuum density

Abstract

We investigate cosmological solutions of Brans-Dicke theory with both the vacuum energy density and the gravitational constant decaying linearly with the Hubble parameter. A particular class of them, with constant deceleration factor, sheds 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 these solutions, we obtain cosmological parameters in accordance with observations of both the relative matter density and the universe age. In addition, we have three other solutions, with Brans-Dicke parameter w = -1 and negative cosmological term, two of them with a future singularity of big-rip type. Although interesting from the theoretical point of view, two of them are not in agreement with the observed universe. The third one leads, in the limit of large times, to a constant relative matter density, being also a possible solution to the cosmic coincidence problem.

arXiv commentMinor changes, references added. Version accepted for publication in Classical and Quantum Gravity

Cited by in corpus (20)

• Hubble expansion & Structure Formation in Time Varying Vacuum Models
• Expansion History with Decaying Vacuum: A Complete Cosmological Scenario
• Complete Cosmic History with a dynamical Lambda(H) term
• Observational constraints on late-time Lambda(t) cosmology
• The spherical collapse model in time varying vacuum cosmologies
• Effective equation of state for running vacuum: "mirage" quintessence and phantom dark energy
• Cosmological implications and structure formation from a time varying vacuum
• Anisotropic Cosmological Model in Modified Brans--Dicke Theory
• Observational tests for Λ(t)CDM cosmology
• Non-adiabatic perturbations in decaying vacuum cosmology
• Evolution of density perturbations in decaying vacuum cosmology: The case of non-zero perturbations in the cosmological term
• Modified Brans-Dicke Theory in Arbitrary Dimensions
• Noncommutative minisuperspace, gravity-driven acceleration and kinetic inflation
• Solving the main cosmological puzzles with a generalized time varying vacuum energy
• Running vacuum in Brans-Dicke theory: a possible cure for the ${\sigma }_8$ and $H_0$ tensions
• From de Sitter to de Sitter: A non-singular inflationary universe driven by vacuum
• Matter Perturbations in Scaling Cosmology
• Baryonic matter perturbations in decaying vacuum cosmology
• Extended holographic Ricci dark energy in chameleon Brans-Dicke cosmology
• Modified Brans-Dicke cosmology with Minimum Length Uncertainty