标题： 引力辐射在霍拉瓦引力中 显示英文标题

标题： Gravitational Radiation in Hořava Gravity

摘要： 我们研究在霍拉瓦引力低能极限下自引力双星系统辐射引力波的情况。 我们发现，广义相对论的能量损失公式预测在牛顿源中已经发生变化：四极矩贡献被改变，部分原因是张量模式的传播速度不同；此外，还存在一个单极矩贡献，源自额外的标量自由度。 偶极矩贡献仅在更高阶的后牛顿级数中出现。 我们利用这些发现，通过与双脉冲星观测到的辐射阻尼进行比较，来限制霍拉瓦引力的低能作用量。 即使这种比较并不完全合适——因为致密天体无法在后牛顿近似中描述——它仍提供了一个数量级的估计。 在后牛顿度规与广义相对论一致的极限情况下，我们的能量损失公式为低能霍拉瓦引力提供了最强的约束。 显示英文摘要

摘要： We study the radiation of gravitational waves by self-gravitating binary systems in the low-energy limit of Ho\v{r}ava gravity. We find that the predictions for the energy-loss formula of General Relativity are modified already for Newtonian sources: the quadrupole contribution is altered, in part due to the different speed of propagation of the tensor modes; furthermore, there is a monopole contribution stemming from an extra scalar degree of freedom. A dipole contribution only appears at higher post-Newtonian order. We use these findings to constrain the low-energy action of Ho\v{r}ava gravity by comparing them with the radiation damping observed for binary pulsars. Even if this comparison is not completely appropriate - since compact objects cannot be described within the post-Newtonian approximation - it represents an order of magnitude estimate. In the limit where the post-Newtonian metric coincides with that of General Relativity, our energy-loss formula provides the strongest constraints for Ho\v{r}ava gravity at low-energies.