Constraints on scalar-tensor models of dark energy from observational and local gravity tests
Constraints on scalar-tensor models of dark energy from observational and local gravity tests
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DOI：
10.1103/physrevd.77.103009
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发表时间：
2008-03
影响因子：
5
通讯作者：
S. Tsujikawa;K. Uddin;S. Mizuno;R. Tavakol;J. Yokoyama
中科院分区：
文献类型：
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作者：
S. Tsujikawa;K. Uddin;S. Mizuno;R. Tavakol;J. Yokoyama
我们构建了一个家庭的可行的标量张量模型的暗能量（DE）具有一个阶段的后期加速之前的标准物质时代，而在同一时间满足当地的重力约束（LGC）。在我们的方案中，标量场和爱因斯坦框架中的非相对论性物质之间的耦合Q被假定为常数，这是对应于耦合Q=-1/{radical}（6）的f（R）引力理论的推广。我们发现，这些模型可以与当地的重力约束兼容，即使当|Q|是通过变色龙机制的统一的顺序，如果标量场电位被选择为具有足够大的质量在高曲率区域。我们发现，这些模型通常会导致发散的状态方程的DE，这发生在较小的红移的偏离{lambda}CDM模型变得更加显着。我们还研究了物质密度扰动的演化，并利用它们来限制耦合|Q|以及从物质功率谱和宇宙微波背景（CMB）各向异性的观测场电位的模型参数。我们发现，只要|Q|小于单位的阶数，存在与观测和局部重力约束一致的允许参数区域。«少
We construct a family of viable scalar-tensor models of dark energy (DE) which possess a phase of late-time acceleration preceded by a standard matter era, while at the same time satisfying the local gravity constraints (LGC). The coupling Q between the scalar field and the nonrelativistic matter in the Einstein frame is assumed to be constant in our scenario, which is a generalization of f(R) gravity theories corresponding to the coupling Q=-1/{radical}(6). We find that these models can be made compatible with local gravity constraints even when |Q| is of the order of unity through a chameleon mechanism, if the scalar-field potential is chosen to have a sufficiently large mass in the high-curvature regions. We show that these models generally lead to the divergence of the equation of state of DE, which occurs at smaller redshifts as the deviation from the {lambda}CDM model becomes more significant. We also study the evolution of matter density perturbations and employ them to place bounds on the coupling |Q| as well as model parameters of the field potential from observations of the matter power spectrum and the cosmic microwave background (CMB) anisotropies. We find that, as long as |Q| is smaller than the ordermore » of unity, there exist allowed parameter regions that are consistent with both observational and local gravity constraints.« less