Non-uniqueness of massless transverse-traceless graviton
Non-uniqueness of massless transverse-traceless graviton
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DOI：
10.1088/1475-7516/2021/05/071
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发表时间：
2021-03
影响因子：
6.4
通讯作者：
K. Aoki;Francesco Di Filippo;S. Mukohyama
中科院分区：
文献类型：
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作者：
K. Aoki;Francesco Di Filippo;S. Mukohyama
我们研究了一个理论的最小修改重力称为cuscuton/VCDM，传播只有两个重力自由度。尽管与广义相对论（GR）明显不同，但原则上，这个理论可以通过从GR作用量开始的场重新定义来获得。这将使真空理论等价于GR，并且该理论与GR的不同之处仅在于存在物质。本文通过研究引力波的色散关系和Bianchi-I宇宙的动力学，证明了这种场的重新定义是不存在的，并且该理论与真空中的GR已经不同。
We study a theory of minimally modified gravity called cuscuton/VCDM that propagates only two gravitational degrees of freedom. Despite being apparently different from general relativity (GR), it is in principle possible that this theory might be obtained via a field redefinition starting from the GR action. This would make the vacuum theory equivalent to GR and the theory would differ from GR only in the presence of matter. In this paper, studying the dispersion relation of gravitational waves and the dynamics of the Bianchi-I universe, we prove that such a field redefinition does not exist and that the theory differs from GR already in vacuum.