论文标题
引力波在宇宙中传播的极化的旋转
Rotations of the polarization of a gravitational wave propagating in Universe
论文作者
论文摘要
在本文中，我们研究了由天体物理源在宇宙距离上发出的引力波（GW）的极化，该距离通过弗里德曼·莱玛·罗伯森 - 罗伯逊 - 漫游世界传播。通过考虑无效的地球偏差，我们首先提供了沿无效的地理位置的平行传输框架，对GW的极化定义，然后明确地显示出宇宙扩展在二极化模式的不同时期，当时二极化的范围是所谓的“ $” $ $ \ $ $ \ $ $ \ $ \ $ \ $ \ $ \ $ $ \ $ $ \ $ $ \ $ $ \ $ $ \ $ \ $ \ $。它正在通过弯曲的背景传播。通过对极化角度的直接计算，我们表明不同的时期，辐射，物质和$λ$二元对极化有不同的影响。特别是，对于由二进制系统发出的GW，我们明确发现了偏振角$ |Δφ| $的变化与源的红移$ z_s $之间的关系。在$λ$ CDM型号中，我们发现$ |Δφ| {η_0f} $的顺序通常是$ o（10^{ - 3}）$ to $ o（10^3）$（10^3）$ $ f \ equiv \ big（\ frac {5} {256} \ frac {1} {τ_{τ_{obs}} \ big）二进制系统的chirp质量。
In this paper, we study the polarization of a gravitational wave (GW) emitted by an astrophysical source at a cosmic distance propagating through the Friedmann-Lemaître-Robertson-Walk universe. By considering the null geodesic deviations, we first provide a definition of the polarization of the GW in terms of the Weyl scalars with respect to a parallelly-transported frame along the null geodesics, and then show explicitly that, due to different effects of the expansion of the universe on the two polarization modes, the so-called "+" and "$\times$" modes, the polarization angle of the GW changes generically, when it is propagating through the curved background. By direct computations of the polarization angle, we show that different epochs, radiation-, matter- and $Λ$-dominated, have different effects on the polarization. In particular, for a GW emitted by a binary system, we find explicitly the relation between the change of the polarization angle $|Δφ|$ and the redshift $z_s$ of the source in different epochs. In the $Λ$CDM model, we find that the order of $|Δφ|{η_0 F}$ is typically $O(10^{-3})$ to $O(10^3)$, depending on the values of $z_s$, where $η_0$ is the (comoving) time of the current universe, and $F\equiv\Big(\frac{5}{256}\frac{1}{τ_{obs}}\Big)^{3/8}\left(G_NM_c\right)^{-5/8}$ with $τ_{obs}$ and $M_c$ being, respectively, the time to coalescence in the observer's frame and the chirp mass of the binary system.
