Chameleon dark energy models with characteristic signatures
Oct, 2010
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Abstract: (arXiv)
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.- 04.50.Kd
- 95.36.+x
- gravitation: local
- gravitation: constraint
- gravitation: f(R)
- matter: density: perturbation
- chameleon: potential
- dark energy
- background
- numerical calculations
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Figures(10)