论文标题
扭曲的角度动量的切割
Cut-continuity of twistor angular momentum
论文作者
论文摘要
Chen等。最近辩称，在邦迪（Bondi-Sachs）的空间时间中，SCRI（零无穷大）的角动量应与切割的位置不断变化（但不依赖其衍生物）。他们表明，这种属性是通过某些定义享受的，但没有享受。我在这里表明扭曲器的定义具有这种连续性。该论点与Chen等人的不同，而SCRI的不变几何形状处于最前沿。从两个无限分离的切割之间发出的角动量的意义上，通量计算出来。这种通量可以解释为相对于切割的角动量的第一个变化。检查第二个变化时，发现扭曲器的定义与大多数其他变化不同，对不同渐近方向之间的辐射相关性做出了反应。因此，扭曲的角动量对渐近场中的定性结构敏感，而不是当前使用的结构。
Chen et al. argued recently that, in Bondi-Sachs space-times, the angular momentum at scri (null infinity) should vary continuously with the position of the cut (but not depend sensitively on its derivatives); they showed that this property was enjoyed by some definitions but not others. I show here that the twistor definition has this continuity. The argument is rather different from Chen et al.'s, with the invariant geometry of scri at the forefront. The flux, in the sense of the angular momentum emitted between two infinitesimally separated cuts, is calculated; this flux can be interpreted as the first variation of the angular momentum with respect to the cut. Examining the second variation, one finds that the twistor definition, unlike most others, responds to correlations in radiation between different asymptotic directions. The twistor angular momentum is thus sensitive to qualitatively different structure in the asymptotic field than are the currently more used ones.
