Persistent gravitational wave observables: Curve deviation in asymptotically flat spacetimes
Persistent gravitational wave observables: Curve deviation in asymptotically flat spacetimes
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DOI：
10.1103/physrevd.105.024056
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发表时间：
2021-09
影响因子：
5
通讯作者：
Alexander M. Grant;D. Nichols
中科院分区：
文献类型：
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作者：
Alexander M. Grant;D. Nichols
在本系列的第一篇论文中，我们引入了一类广义引力波记忆效应的观测量，并将其命名为“持续引力波观测量”。“这些可观测量在时间上都是非局部的，在具有引力辐射的时空中是非零的，并且在引力波通过后仍然存在可观测的效应。在本文中，我们专注于持久的可观测称为“曲线偏差“，我们计算的可观测使用邦迪-萨克斯方法渐近平坦时空的领先，非平凡的顺序在逆邦迪半径。曲线偏差与具有初始分离、初始相对速度和相对加速度的两个观察者的最终分离有关。位移引力波记忆效应是依赖于初始分离的曲线偏差的一部分，并且是初始共动的惯性观测者在大Bondi半径下的全部贡献。自旋和质心记忆效应包含在曲线偏差对初始相对速度的依赖关系中，而曲线偏差对相对加速度的依赖关系包含与这些已知记忆效应不同的可观测量。我们发现，可以观察到的全曲线偏差可以写在辐射（我们称之为“电荷“的贡献）之前和之后的非辐射数据的差异，沿着的非线性“通量“的贡献，在引力辐射的情况下消失。这种分裂将位移、自旋和质心引力波记忆效应中存在的“普通“和“零“记忆的概念推广到了可观察到的全曲线偏差。
In the first paper in this series, a class of observables that generalized the gravitational wave memory effect were introduced and given the name"persistent gravitational wave observables."These observables are all nonlocal in time, nonzero in spacetimes with gravitational radiation, and have an observable effect that persists after the gravitational waves have passed. In this paper, we focus on the persistent observable known as"curve deviation,"and we compute the observable using the Bondi-Sachs approach to asymptotically flat spacetimes at the leading, nontrivial order in inverse Bondi radius. The curve deviation is related to the final separation of two observers who have an initial separation, initial relative velocity, and relative acceleration. The displacement gravitational wave memory effect is the part of the curve deviation that depends on the initial separation and is the entire contribution for initially comoving, inertial observers at large Bondi radius. The spin and center-of-mass memory effects are contained within the dependence of the curve deviation on the initial relative velocity, and the dependence of the curve deviation on relative acceleration contains observables distinct from these known memory effects. We find that the full curve deviation observable can be written in terms of differences in nonradiative data before and after the radiation (which we call the"charge"contribution), along with a nonlinear"flux"contribution that vanishes in the absence of gravitational radiation. This splitting generalizes the notion of"ordinary"and"null"memory that exists for the displacement, spin, and center-of-mass gravitational wave memory effects to the full curve deviation observable.