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Physical Review D (2010) 124006
Chameleon dark energy models with characteristic signatures
Radouane Gannouji, Bruno Moraes, David F. Mota, David Polarski1, Shinji Tsujikawa, Hans A. Winther

In chameleon dark energy models, local gravity constraints tend to rule out parameters in which observable cosmological signatures can be found. We study viable chameleon potentials consistent with a number of recent observational and experimental bounds. A novel chameleon field potential, motivated by f(R) gravity, is constructed where observable cosmological signatures are present both at the background evolution and in the growth-rate of the perturbations. We study the evolution of matter density perturbations on low redshifts for this potential and show that the growth index today gamma_0 can have significant dispersion on scales relevant for large scale structures. The values of gamma_0 can be even smaller than 0.2 with large variations of gamma on very low redshifts for the model parameters constrained by local gravity tests. This gives a possibility to clearly distinguish these chameleon models from the Lambda-Cold-Dark-Matter model in future high-precision observations.
1 :  LPTA - Laboratoire de Physique Théorique et Astroparticules
Planète et Univers/Astrophysique/Cosmologie et astrophysique extra-galactique

Physique/Astrophysique/Cosmologie et astrophysique extra-galactique

Physique/Relativité Générale et Cosmologie Quantique

Physique/Physique des Hautes Energies - Phénoménologie

Physique/Physique des Hautes Energies - Théorie
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