f(R) gravity and chameleon theories
f(R) gravity and chameleon theories
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DOI：
10.1103/physrevd.78.104021
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发表时间：
2008-06
影响因子：
5
通讯作者：
P. Brax;C. V. D. Bruck;A. Davis;D. Shaw
中科院分区：
文献类型：
--
作者：
P. Brax;C. V. D. Bruck;A. Davis;D. Shaw
我们分析了爱因斯坦引力的f（R）修正作为暗能量模型与变色龙理论的联系。f（R）理论以标量-张量理论的形式表述，暗示标量场与物质之间存在强耦合。这将违反所有关于牛顿定律偏差的实验引力测试。幸运的是，物质依赖性质量和薄壳效应的存在允许人们减轻这些限制。薄壳条件也意味着对f（R）理论的宇宙动力学的强限制。因此，我们发现暗能量的状态方程在最近的过去被限制为非常接近-1。我们还研究了Eoet-wash实验中f（R）理论的潜在影响。我们表明，测试机构的薄壳的要求是不够的，以保证从牛顿定律的偏差为零的结果。只要暗能量占宇宙总能量密度的相当大的一部分，我们推导出的约束也禁止暗能量状态方程与-1有任何可测量的偏差。总而言之，我们发现宇宙学和实验室测试都意味着f（R）模型在背景水平上几乎与{lambda}CDM模型重合。«少
We analyze f(R) modifications of Einstein's gravity as dark energy models in the light of their connection with chameleon theories. Formulated as scalar-tensor theories, the f(R) theories imply the existence of a strong coupling of the scalar field to matter. This would violate all experimental gravitational tests on deviations from Newton's law. Fortunately, the existence of a matter dependent mass and a thin-shell effect allows one to alleviate these constraints. The thin-shell condition also implies strong restrictions on the cosmological dynamics of the f(R) theories. As a consequence, we find that the equation of state of dark energy is constrained to be extremely close to -1 in the recent past. We also examine the potential effects of f(R) theories in the context of the Eoet-wash experiments. We show that the requirement of a thin shell for the test bodies is not enough to guarantee a null result on deviations from Newton's law. As long as dark energy accounts for a sizeable fraction of the total energy density of the Universe, the constraints that we deduce also forbid any measurable deviation of the dark energy equation of state from -1. All in all, we find that both cosmological and laboratory testsmore » imply that f(R) models are almost coincident with a {lambda}CDM model at the background level.« less