论文标题
标量和矢量尾部辐射从灯具的内部
Scalar and vector tail radiation from the interior of the lightcone
论文作者
论文摘要
在通用的时空中,无质量的场不仅在源的前灯光表面传播,而且在其内部传播。这种内部光线“尾辐射”通常被描述为在时空曲率上具有“散射”。在这项工作中,我们研究了这种尾辐射的传播,以使紧凑,静态,球形对称的弱场(即低密度)质量分布远离源和观察者之间的视线(LOS),并且仅在重力上耦合到辐射。对于这样的遗物,观察到的辐射中有四个不同的时期:轻圆形片;随后的早期尾巴 - 首次以光速移动的信号可以从源头传播到观察者的点。随后的中间尾巴;而后期的尾巴是从上次发出信号可以进行这样的旅程的最后时间。对于无质量标量和矢量(例如电磁辐射),我们重新审视了先前研究的早期和晚期尾巴,并对中间尾巴进行了首次完整检查。研究较短的波长和通用的遗物,我们发现较晚的尾巴带有观察者收到的能量的一小部分。但是,总尾巴含有更多能量。我们还注意到,尽管观察者似乎中间尾巴从perturber中散发出来 - 正如人们可能期望从重力扰动中“散射”的辐射,但后期的尾巴似乎从源头回来了。我们推测这种中间尾巴的潜在效用是检测或探测对时空几何形状(包括暗物质候选者和暗物质光环)的各种扰动的潜在效用。
In a generic spacetime a massless field propagates not just on the surface of the forward lightcone of a source, but in its interior. This inside-the-lightcone "tail radiation" is often described as having "scattered" off the spacetime curvature. In this work, we study the propagation of such tail radiation for a compact, static, spherically symmetric weak-field (i.e. low density) mass distribution that is well off the line-of-sight (LOS) between a source and an observer, and that is coupled to the radiation only gravitationally. For such perturbers, there are four distinct epochs in the observed radiation: the light-cone piece; the subsequent early-time tail -- ending at the first time that a signal moving at the speed of light could travel from the source to a point in the perturber thence to the observer; the subsequent middle-time tail; and the late-time tail, beginning at the last time that a signal could make such a journey. For massless scalar and vector (eg. electromagnetic radiation), we revisit the previously studied early and late-time tail, and perform the first full examination of the middle-time tail. Studying shorter wavelengths and generic perturbers well off the LOS, we find that the late-time tail carries a small fraction of the energy received by the observer; however, the total middle-time tail contains much more energy. We also note that whereas the middle-time tail appears to the observer to emanate from the perturber -- as one might expect for radiation "scattered" from the gravitational perturbation -- the late-time tail appears to come back from the source. We speculate on the potential utility of this middle-time tail for detecting or probing a wide variety of perturbations to the spacetime geometry including dark matter candidates and dark matter halos.