%0 Journal Article
%T The growth of matter perturbations in f(R) models
%+ Laboratoire de Physique Théorique et Astroparticules (LPTA)
%A Gannouji, Radouane
%A Moraes, Bruno
%A Polarski, David
%< avec comité de lecture
%Z 09-078
%@ 1475-7508
%J Journal of Cosmology and Astroparticle Physics
%I Institute of Physics (IOP)
%V 02
%P 034
%8 2009-02-26
%D 2009
%Z 0809.3374
%R 10.1088/1475-7516/2009/02/034
%K dark energy theory
%K cosmological perturbation theory
%Z Physics [physics]/General Relativity and Quantum Cosmology [gr-qc]
%Z Physics [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE]
%Z Sciences of the Universe [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE]Journal articles
%X We consider the linear growth of matter perturbations on low redshifts insome $f(R)$ dark energy (DE) models. We discuss the definition of dark energy(DE) in these models and show the differences with scalar-tensor DE models. Forthe $f(R)$ model recently proposed by Starobinsky we show that the growthparameter $\gamma_0\equiv \gamma(z=0)$ takes the value $\gamma_0\simeq 0.4$ for$\Omega_{m,0}=0.32$ and $\gamma_0\simeq 0.43$ for $\Omega_{m,0}=0.23$, allowingfor a clear distinction from $\Lambda$CDM. Though a scale-dependence appears inthe growth of perturbations on higher redshifts, we find no dispersion for$\gamma(z)$ on low redshifts up to $z\sim 0.3$, $\gamma(z)$ is alsoquasi-linear in this interval. At redshift $z=0.5$, the dispersion is stillsmall with $\Delta \gamma\simeq 0.01$. As for some scalar-tensor models, wefind here too a large value for $\gamma'_0\equiv \frac{d\gamma}{dz}(z=0)$,$\gamma'_0\simeq -0.25$ for $\Omega_{m,0}=0.32$ and $\gamma'_0\simeq -0.18$ for$\Omega_{m,0}=0.23$. These values are largely outside the range found for DEmodels in General Relativity (GR). This clear signature provides a powerfulconstraint on these models.
%G English
%L hal-00430271
%U https://hal.science/hal-00430271
%~ IN2P3
%~ LPTA
%~ CNRS
%~ UNIV-MONTP2
%~ UNIV-MONTPELLIER
%~ UM1-UM2