2008/03/07 by Shinji Tsujikawa, Kotub Uddin, Shuntaro Mizuno +3 · 2 citations
Earth and Planetary Sciences · Physics and Astronomy · #Anisotropy #Astrophysics #Black Holes and Theoretical Physics #Classical mechanics #Cosmic microwave background #Cosmology #Cosmology and Gravitation Theories #Dark energy #Dark matter #Equation of state #Geometry #Geophysics and Gravity Measurements #Mathematical physics #Matter power spectrum #Physics #Quantum gravity #Quantum mechanics #Scalar (mathematics) #Scalar field #Theoretical physics #astro-ph #f(R) gravity #gr-qc #hep-ph #hep-th
paper · pdf · doi:10.1103/physrevd.77.103009
published as Phys.Rev.D77:103009,2008 · 24 pages including 5 figures. Submitted to PRD
arxiv created 2008/03/07 · openalex publication_date 2008/05/21 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We construct a family of viable scalar-tensor models of dark energy (DE) which possess a phase of late-time acceleration preceded by a standard matter era, while at the same time satisfying the local gravity constraints (LGC). The coupling Q between the scalar field and the nonrelativistic matter in the Einstein frame is assumed to be constant in our scenario, which is a generalization of f(R) gravity theories corresponding to the coupling Q=\ensuremath-1/√(6). We find that these models can be made compatible with local gravity constraints even when |Q| is of the order of unity through a chameleon mechanism, if the scalar-field potential is chosen to have a sufficiently large mass in the high-curvature regions. We show that these models generally lead to the divergence of the equation of state of DE, which occurs at smaller redshifts as the deviation from the \ensuremathΛCDM model becomes more significant. We also study the evolution of matter density perturbations and employ them to place bounds on the coupling |Q| as well as model parameters of the field potential from observations of the matter power spectrum and the cosmic microwave background (CMB) anisotropies. We find that, as long as |Q| is smaller than the order of unity, there exist allowed parameter regions that are consistent with both observational and local gravity constraints.