Gravitational-wave energy and other fluxes in ghost-free bigravity
Gravitational-wave energy and other fluxes in ghost-free bigravity
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DOI：
10.1103/physrevd.107.044041
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发表时间：
2022-08
影响因子：
5
通讯作者：
Alexander M. Grant;A. Saffer;L. Stein;S. Tahura
中科院分区：
文献类型：
--
作者：
Alexander M. Grant;A. Saffer;L. Stein;S. Tahura
在超越GR的引力理论中进行二元波形预测的关键因素之一是理解引力波和任何其他辐射场携带的能量和角动量。确定适当的能量泛函在哈桑-罗森双引力理论中是不清楚的，这是一个没有幽灵的理论，有一个有质量的引力子和一个无质量的引力子。困难来自新的自由度和长度尺度，这是不存在的GR，呈现艾萨克森式的平均计算模糊。本文从作用量出发，用正则流形式计算了双引力中引力波携带的能量。正则流与GR中其他常见的能量计算一致，并且是明确的（模边界项），使其成为量化双引力或任何双态不变引力理论中引力波能量的方便选择。这种计算为未来的双重力波形建模打开了大门，正确地包括由于引力波发射引起的反作用。
One of the key ingredients for making binary waveform predictions in a beyond-GR theory of gravity is understanding the energy and angular momentum carried by gravitational waves and any other radiated fields. Identifying the appropriate energy functional is unclear in Hassan-Rosen bigravity, a ghost-free theory with one massive and one massless graviton. The difficulty arises from the new degrees of freedom and length scales which are not present in GR, rendering an Isaacson-style averaging calculation ambiguous. In this article we compute the energy carried by gravitational waves in bigravity starting from the action, using the canonical current formalism. The canonical current agrees with other common energy calculations in GR, and is unambiguous (modulo boundary terms), making it a convenient choice for quantifying the energy of gravitational waves in bigravity or any diffeomorphism-invariant theories of gravity. This calculation opens the door for future waveform modeling in bigravity to correctly include backreaction due to emission of gravitational waves.