We derive consistent equations for gravitational wave oscillations in bigravity. In this framework a second dynamical tensor field is introduced in addition to general relativity and coupled such that one massless and one massive linear combination arise. Only one of the two tensors is the physical metric coupling to matter, and thus the basis in which gravitational waves propagate is different from the basis where the wave is produced and detected. Therefore, one should expect—in analogy to neutrino oscillations—to observe an oscillatory behavior. We show for the first time how this behavior arises explicitly, discuss phenomenological implications, and present new limits on the graviton parameter space in bigravity.

中文翻译：

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双引力的引力波振荡

我们导出了双引力中重力波振荡的一致方程。在这个框架中，除了广义相对论之外，还引入了第二个动态张量场，并且耦合了第二个动态张量场，从而产生了一个无质量的和一个质量线性的组合。两个张量中只有一个是与物质的物理量度耦合，因此引力波传播的基础与产生和检测波的基础不同。因此，类似于中微子振荡，人们应该期望观察到振荡行为。我们首次展示了这种行为是如何显式出现的，讨论了现象学的含义，并提出了双引力引力子参数空间的新限制。