Cosmological constraints on Brans-Dicke theory.
Cosmological constraints on Brans-Dicke theory.
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DOI：
10.1103/physrevlett.113.011101
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发表时间：
2013-03
影响因子：
8.6
通讯作者：
A. Avilez;C. Skordis
中科院分区：
文献类型：
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作者：
A. Avilez;C. Skordis
我们使用普朗克的宇宙微波背景数据报告了对布兰斯-迪克（BD）引力理论的强大宇宙学约束。我们考虑两种类型的模型。首先，标量场的初始条件被固定，以提供与今天在地球上测量的相同的有效引力强度 Geff，GN。在这种情况下，BD 参数 ω 在 99% 置信水平下被约束为 ω>692，比之前的约束提高了一个数量级。在第二种类型中，标量的初始条件是自由参数，导致 ω>890 的约束稍强，而在相同置信水平下，Geff 被约束为 0.981<Geff/GN<1.285。我们认为这些约束比 BD 理论具有更大的有效性，并且对于任何 Horndeski 理论（最通用的二阶标量张量理论）都有效，它在宇宙学尺度上近似 BD 理论。从这个意义上说，我们的约束对可能解释宇宙加速的引力的可能修改施加了严格的限制。
We report strong cosmological constraints on the Brans-Dicke (BD) theory of gravity using cosmic microwave background data from Planck. We consider two types of models. First, the initial condition of the scalar field is fixed to give the same effective gravitational strength Geff today as the one measured on Earth, GN. In this case, the BD parameter ω is constrained to ω>692 at the 99% confidence level, an order of magnitude improvement over previous constraints. In the second type, the initial condition for the scalar is a free parameter leading to a somewhat stronger constraint of ω>890, while Geff is constrained to 0.981<Geff/GN<1.285 at the same confidence level. We argue that these constraints have greater validity than for the BD theory and are valid for any Horndeski theory, the most general second-order scalar-tensor theory, which approximates the BD theory on cosmological scales. In this sense, our constraints place strong limits on possible modifications of gravity that might explain cosmic acceleration.