Constraining f( R) gravity in solar system, cosmology and binary pulsar systems

摘要

The f ( R ) gravity can be cast into the form of a scalar–tensor theory, and scalar degree of freedom can be suppressed in high-density regions by the chameleon mechanism. In this article, for the general f ( R ) gravity, using a scalar–tensor representation with the chameleon mechanism, we calculate the parametrized post-Newtonian parameters γ and β , the effective gravitational constant G eff , and the effective cosmological constant Λ eff . In addition, for the general f ( R ) gravity, we also calculate the rate of orbital period decay of the binary system due to gravitational radiation. Then we apply these results to specific f ( R ) models (Hu–Sawicki model, Tsujikawa model and Starobinsky model) and derive the constraints on the model parameters by combining the observations in solar system, cosmological scales and the binary systems.