Evolution of density perturbations in f(R) gravity

By Sante Carloni, P. Dunsby, Antonio Troisi. 2007

133 citations recorded by the source corpus.

We give a rigorous and mathematically well defined presentation of the covariant and gauge invariant theory of scalar perturbations of a Friedmann-Lema\^{\i}tre-Robertson-Walker universe for fourth order gravity, where the matter is described by a perfect fluid with a barotropic equation of state. The general perturbations equations are applied to a simple background solution of ${R}^{n}$ gravity. We obtain exact solutions of the perturbations equations for scales much bigger than the Hubble radius. These solutions have a number of interesting features. In particular, we find that for all values of $n$ there is always a growing mode for the density contrast, even if the universe undergoes an accelerated expansion. Such behavior does not occur in standard general relativity, where as soon as dark energy dominates, the density contrast experiences an unrelenting decay. This peculiarity is sufficiently novel to warrant further investigation of fourth order gravity models.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/11f9fc9bd56e8b1ee3ecd225fc4517d56d66f11d

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Citations in the corpus

Modified Gravity and Cosmology (2011, background): “The equivalent equations to those given above can also be derived in the covariant approach to cosmological perturbation theory [250].”
f(R) Theories (2010, methodology): “Perturbing Einstein equations at linear order, we obtain the following equations [316, 317] (see also [436, 566, 355, 438, 312, 313, 314, 492, 138, 33, 441, 328])”
f(R) Theories Of Gravity (2008, background): “…originated various efforts to constrain f(R) gravity with cosmic microwave background data (Amendola and Tsujikawa, 2008; Appleby and Battye, 2007; Carloni et al., 2008b; Hu and Sawicki, 2007b; Li and Barrow, 2007; Li et al., 2007a; Pogosian and Silvestri, 2008; Starobinsky, 2007; Tsujikawa,…”
A Bird's Eye View of f (R)-Gravity (2009, methodology): “A rigorous and mathematically selfconsistent approach to the problem of cosmological perturbations in ) (R f -gravity as been developed using covariant and gauge-invariant quantities in [101-103].”