Constraints on scalar-tensor models of dark energy from observational and local gravity tests

By S. Tsujikawa, Kotub Uddin, S. Mizuno, R. Tavakol, J. Yokoyama. 2008

137 citations recorded by the source corpus.

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=-1/{radical}(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 {lambda}CDM 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 ordermore » of unity, there exist allowed parameter regions that are consistent with both observational and local gravity constraints.« less

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics, Oceanography

View Paper: https://www.semanticscholar.org/paper/aa4d880f2ce5853de58f6caa64f2690db1e60837

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Citations in the corpus

Cosmology and Fundamental Physics with the Euclid Satellite (2012, background): “4, those that remain viable are the subset that very closely mimic the standard ΛCDM background expansion, as this restricted subclass of models can evade solar system constraints [308, 1178, 548], have a standard matter era in which the scale factor evolves according to a(t) ∝ t [58] and can also b”
f(R) Theories (2010, methodology): “, [596, 22, 85, 289, 5, 327, 139, 168] for dynamical analysis in scalar-tensor theories).”