Improved Cauchy-characteristic evolution system for high-precision numerical relativity waveforms
Improved Cauchy-characteristic evolution system for high-precision numerical relativity waveforms
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DOI：
10.1103/physrevd.102.044052
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发表时间：
2020-07
影响因子：
5
通讯作者：
Jordan Moxon;M. Scheel;S. Teukolsky
中科院分区：
文献类型：
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作者：
Jordan Moxon;M. Scheel;S. Teukolsky
我们提出了几个改进的柯西特征演化过程，产生高保真度的引力波形在I+从数值相对论模拟。柯西特征演化结合了基于柯西切片的爱因斯坦场方程的内部解和基于扩展到I+的零切片的外部解。我们改进算法的基础是一个全面的方法来处理规范之间的任意指定的坐标的内部柯西演化和唯一的（高达Bondi-Metzner-Sachs群变换）Bondi-Sachs坐标系的外部特征演化的转换。我们提出了一套重新制定的特征演化方程更好地适应数值实现。此外，我们开发了一种方法，以确保在体积中使用的角坐标的特性的演变过程中是渐近惯性。这提供了一个直接的路线，以扩大一组波形输出，并保证避免纯规格的对数依赖性，造成的麻烦，以前的频谱实现的特征演变方程。我们构造了一组与特征演化中使用的Bondi坐标系兼容的Weyl标量，并确定了我们建议的坐标系中的渐近Weyl标量的简单，易于实现的形式。
We present several improvements to the Cauchy-characteristic evolution procedure that generates high-fidelity gravitational waveforms at I+ from numerical relativity simulations. Cauchy-characteristic evolution combines an interior solution of the Einstein field equations based on Cauchy slices with an exterior solution based on null slices that extend to I+. The foundation of our improved algorithm is a comprehensive method of handling the gauge transformations between the arbitrarily specified coordinates of the interior Cauchy evolution and the unique (up to Bondi-Metzner-Sachs group transformations) Bondi-Sachs coordinate system of the exterior characteristic evolution. We present a reformulated set of characteristic evolution equations better adapted to numerical implementation. In addition, we develop a method to ensure that the angular coordinates used in the volume during the characteristic evolution are asymptotically inertial. This provides a direct route to an expanded set of waveform outputs and is guaranteed to avoid pure-gauge logarithmic dependence that has caused trouble for previous spectral implementations of the characteristic evolution equations. We construct a set of Weyl scalars compatible with the Bondi-like coordinate systems used in characteristic evolution and determine simple, easily implemented forms for the asymptotic Weyl scalars in our suggested set of coordinates.