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arXiv 0910.0207gr-qc
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Schwarzschild几何中圆轨道引力自作用力的后牛顿和数值计算

Post-Newtonian and Numerical Calculations of the Gravitational Self-Force for Circular Orbits in the Schwarzschild Geometry

Luc Blanchet, Steven Detweiler, Alexandre Le Tiec, Bernard F. Whiting

摘要:

利用广义相对论中两种不同的近似方法,讨论了在圆轨道上运动的紧凑双星系统的问题。后牛顿(PN)近似涉及v/c<<1的幂展开,并且最适合于小轨道速度v。微扰自作用力(SF)分析要求双星的组分有一个极端的质量比m1/m2<<1。一个特定的坐标不变的可观测量确定为使用这两种不同的近似系统的轨道频率的函数。后牛顿计算被推到第三后牛顿(3 PN)阶。它涉及由两个点粒子生成的度量,并在其中一个粒子的位置处进行评估。我们用维数正则化的方法正则化了粒子的发散自场。我们表明,比例1/(d-3)出现在三维正则化在3 PN阶的极点从最终的规范不变的可观察性抵消。3 PN的解析结果,通过一阶的质量比,和数值SF计算一致。这种跨文化比较的一致性证实了这两种近似在描述紧凑的双星系统中的可靠性。特别是,它提供了一个独立的测试非常不同的正则化程序中调用的两个近似方案。

英文摘要:

The problem of a compact binary system whose components move on circular orbits is addressed using two different approximation techniques in general relativity. The post-Newtonian (PN) approximation involves an expansion in powers of v/c<<1, and is most appropriate for small orbital velocities v. The perturbative self-force (SF) analysis requires an extreme mass ratio m1/m2<<1 for the components of the binary. A particular coordinate-invariant observable is determined as a function of the orbital frequency of the system using these two different approximations. The post-Newtonian calculation is pushed up to the third post-Newtonian (3PN) order. It involves the metric generated by two point particles and evaluated at the location of one of the particles. We regularize the divergent self-field of the particle by means of dimensional regularization. We show that the poles proportional to 1/(d-3) appearing in dimensional regularization at the 3PN order cancel out from the final gauge invariant observable. The 3PN analytical result, through first order in the mass ratio, and the numerical SF calculation are found to agree well. The consistency of this cross cultural comparison confirms the soundness of both approximations in describing compact binary systems. In particular, it provides an independent test of the very different regularization procedures invoked in the two approximation schemes.

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