The evolution of density perturbations in f(R) gravity

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dc.creatorCarloni, S.
dc.creatorDunsby, P. K. S.
dc.creatorTroisi, A.
dc.date2007-07-01
dc.date2007-07-04
dc.date.accessioned2026-07-07T11:17:23Z
dc.date.available2026-07-07T11:17:23Z
dc.descriptionWe give a rigorous and mathematically well defined presentation of the Covariant and Gauge Invariant theory of scalar perturbations of a Friedmann-Lemaitre-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 a behaviour 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 on fourth order gravity models.
dc.description21 pages, 2 figures, typos corrected, submitted to PRD
dc.identifierhttps://arxiv.org/abs/0707.0106
dc.identifierhttp://arxiv.org/abs/0707.0106
dc.identifierPhys.Rev.D77:024024,2008
dc.identifierdoi:10.1103/PhysRevD.77.024024
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/192992
dc.subjectGeneral Relativity and Quantum Cosmology
dc.subjectAstrophysics
dc.subjectHigh Energy Physics - Theory
dc.titleThe evolution of density perturbations in f(R) gravity
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