Standard Cosmological Evolution in a Wide Range of f(R) Models

Abstract

Using techniques from singular perturbation theory, we explicitly calculate the cosmological evolution in a class of modified gravity models. By considering the (m)CDTT model, which aims to explain the current acceleration of the universe with a modification of gravity, we show that Einstein evolution can be recovered for most of cosmic history in at least one f(R) model. We show that a standard epoch of matter domination can be obtained in the mCDTT model, providing a sufficiently long epoch to satisfy observations. We note that the additional inverse term will not significantly alter standard evolution until today and that the solution lies well within present constraints from Big Bang Nucleosynthesis. For the CDTT model, we analyse the ``recent radiation epoch'' behaviour (a \propto t^{1/2}) found by previous authors. We finally generalise our findings to the class of inverse power-law models. Even in this class of models, we expect a standard cosmological evolution, with a sufficient matter domination era, although the sign of the additional term is crucial.

15 pages, 6 figures (1 new figure), new version considers both CDTT and mCDTT models. References added. Accepted by Phys Rev D

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Cited by in corpus (6)

• Future of the universe in modified gravitational theories: Approaching to the finite-time future singularity
• f(R) Gravity and Chameleon Theories
• The future evolution and finite-time singularities in $F(R)$-gravity unifying the inflation and cosmic acceleration
• Dark energy, inflation and dark matter from modified F(R) gravity
• Initial and final de Sitter universes from modified $f(R)$ gravity
• Delicate f(R) gravity models with disappearing cosmological constant and observational constraints on the model parameters