Linearized f(R) gravity: Gravitational radiation and Solar System tests
Linearized f(R) gravity: Gravitational radiation and Solar System tests
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DOI：
10.1103/physrevd.83.104022
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发表时间：
2011-03-11
影响因子：
5
通讯作者：
Gair, Jonathan R.
中科院分区：
文献类型：
--
作者：
Berry, Christopher P. L.;Gair, Jonathan R.
本文研究了度规f（R）-引力的线性化形式，假定f（R）在R = 0附近解析，则可展开为f（R）R + a（2）R（2）/2 +.引力辐射被修正，允许一个额外的振荡模式，即里奇标量的振荡模式。我们推导出辐射的有效能量动量张量。我们还提出了简单源的弱场度量。这些与等价的克尔（或史瓦西）形式不同。我们将度量应用于可能约束f（R）的测试。我们表明，光偏转实验不能区分f（R）-引力和广义相对论，因为两者都有一个有效的后牛顿参数γ = 1。我们发现行星岁差率相对于广义相对论有所增强;从水星的轨道中，我们推导出束缚垂直棒a（2）垂直棒小于或类似于1：2 x 10（18）m（2）。引力波天文学可能更有用：考虑到引力波形的相位，我们估计，对于一个10（6）M（圆点）黑洞的极端质量比螺旋，如果竖线大于或近似于10（17）m（2），那么与广义相对论的偏差是可以测量的，假设黑洞的弱场度规与点质量的一致。然而，Eot-Wash实验提供了最严格的边界垂直条，a（2）垂直条小于或接近2 x 10（-9）m（2）。虽然天文界较弱，但在f（R）的有效形式在不同区域被修改的情况下，它们仍然是有趣的，也许是通过变色龙机制。假设实验室束缚是普遍的，我们得出结论，传播的Ricci标量模式不能被天体物理源激发。
We investigate the linearized form of metric f(R)-gravity, assuming that f(R) is analytic about R = 0 so it may be expanded as f(R) R + a(2)R(2)/2 + ... Gravitational radiation is modified, admitting an extra mode of oscillation, that of the Ricci scalar. We derive an effective energy-momentum tensor for the radiation. We also present weak-field metrics for simple sources. These are distinct from the equivalent Kerr (or Schwarzschild) forms. We apply the metrics to tests that could constrain f(R). We show that light deflection experiments cannot distinguish f(R)-gravity from general relativity as both have an effective post-Newtonian parameter gamma = 1. We find that planetary precession rates are enhanced relative to general relativity; from the orbit of Mercury we derive the bound vertical bar a(2)vertical bar less than or similar to 1: 2 x 10(18) m(2). Gravitational-wave astronomy may be more useful: considering the phase of a gravitational waveform we estimate deviations from general relativity could be measurable for an extreme-mass-ratio inspiral about a 10(6)M(circle dot) black hole if vertical bar a(2)vertical bar greater than or similar to 10(17) m(2), assuming that the weak-field metric of the black hole coincides with that of a point mass. However Eot-Wash experiments provide the strictest bound vertical bar a(2)vertical bar less than or similar to 2 x 10(-9) m(2). Although the astronomical bounds are weaker, they are still of interest in the case that the effective form of f(R) is modified in different regions, perhaps through the chameleon mechanism. Assuming the laboratory bound is universal, we conclude that the propagating Ricci scalar mode cannot be excited by astrophysical sources.