标题： 宇宙弦引力场中的量子电动力学 显示英文标题

标题： Quantum Electrodynamics in the Gravitational Field of a Cosmic String

摘要： 我们评估了在静态、直线宇宙弦时空中的单个高能光子产生电子-正电子对的截面。能量和动量守恒在空的闵可夫斯基空间中排除了这一过程的发生。然而，尽管度规具有局部平坦性，这一过程还是发生在宇宙弦周围，这是由于空间的锥状结构所致。先前基于简化模型（标量场）的结果被扩展到了现实的量子电动力学情况。在三种不同的情况下找到了解析表达式：接近阈值时，在能量远大于电子静止质量 M 时，以及在超高能量下，远大于 $M/\delta$，其中 $\delta$ 是以普朗克单位表示的弦的质量线密度。 显示英文摘要

摘要： We evaluate the cross section for electron-positron pair production by a single high energy photon in the space-time of a static, straight cosmic string. Energy and momentum conservation precludes this process in empty Minkowski space. It happens around a cosmic string, in spite of the local flatness of the metric, as a consequence of the conical structure of space. Previous results based on a simplified model with scalar fields are here extended to the realistic QED case. Analytic expressions are found in three different regimes: near the threshold, at energies much larger than the electron rest mass M, and at ultrahigh energies, much larger than $M/\delta$, with $\delta$ the string mass per unit length in Planck units.