Chameleon dark energy models with characteristic signatures

Radouane Gannouji, Bruno Moraes, David F. Mota, David Polarski, Shinji Tsujikawa, Hans A. Winther

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58 Scopus citations


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 γ0 can have significant dispersion on scales relevant for large scale structures. The values of γ0 can be even smaller than 0.2 with large variations of γ 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 Λ-cold-dark-matter (ΛCDM) model in future high-precision observations.

Original languageEnglish
Article number124006
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Issue number12
StatePublished - 2 Dec 2010
Externally publishedYes


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