Chameleon dark energy models with characteristic signatures
Chameleon dark energy models with characteristic signatures
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DOI：
10.1103/physrevd.82.124006
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发表时间：
2010-10
影响因子：
5
通讯作者：
R. Gannouji;B. Moraes;D. Mota;D. Polarski;S. Tsujikawa;H. Winther
中科院分区：
文献类型：
--
作者：
R. Gannouji;B. Moraes;D. Mota;D. Polarski;S. Tsujikawa;H. Winther
在变色龙暗能量模型中，局部重力约束往往会排除可以发现可观测宇宙学特征的参数。我们研究了与最近的一些观察和实验范围一致的可行变色龙潜力。在 $f(R)$ 引力的推动下，构建了一种新颖的变色龙场势，其中可观测的宇宙学特征既存在于背景演化中，也存在于扰动的增长率中。我们研究了这种潜力在低红移下物质密度扰动的演化，并表明今天的增长指数 ${\ensuremath{\gamma}}_{0}$ 在与大规模结构相关的尺度上可能有显着的分散。 ${\ensuremath{\gamma}}_{0}$ 的值甚至可以小于 0.2，在受局部重力测试约束的模型参数的红移非常低的情况下，$\ensuremath{\gamma}$ 的变化很大。这使得在未来的高精度观测中可以清楚地区分这些变色龙模型与 $\ensuremath{\Lambda}$-冷暗物质 ($\ensuremath{\Lambda}\mathrm{CDM}$) 模型。
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 ${\ensuremath{\gamma}}_{0}$ can have significant dispersion on scales relevant for large scale structures. The values of ${\ensuremath{\gamma}}_{0}$ can be even smaller than 0.2 with large variations of $\ensuremath{\gamma}$ 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 $\ensuremath{\Lambda}$-cold-dark-matter ($\ensuremath{\Lambda}\mathrm{CDM}$) model in future high-precision observations.