Ref HAL: hal-00632706_v1
Ref Arxiv: 1010.3769
DOI: 10.1103/PhysRevD.82.124006
WoS: 000208475300007
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
54 Citations
Résumé:

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.

Commentaires: 16 pages, 8 figures Journal: Phys.Rev.D82:124006,2010