Jun-Qi Guo, Andrei V. Frolov
In this paper, we revisit the conditions for cosmological viability of f(R) gravity and formulate them in terms of constraints on the potential of the scalaron field f'. When the scalaron is heavy, f(R) goes to general relativity, and the matter-domination epoch could last long enough to ensure the formation of the large scale structure. The idea of having the Newton's constant change its value depending on the scalar curvature leads to a class of f(R) models. In particular, one obtains an RlnR model when the running of a dimensionless coupling constant is described by a beta-function similar to the one in quantum chromodynamics. In this RlnR model, the effective cosmological constant is exponentially suppressed compared to a reference scale. We explore the phase space dynamics and the cosmological evolution of the model in details.
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http://arxiv.org/abs/1305.7290
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