Abstract An exact momentum update useful for particle codes was previously given. The expressions involved were unwieldy. By treating the momentum as a representation of SU(2) × SU(2) instead of SO(3,1), a more compact expression for the exact momentum update is obtained. An expansion in powers of the timestep can be formulated such that invariance properties are exactly preserved, and push rates comparable to the standard Boris pusher are obtained.

中文翻译：

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用于极端场的特殊整体粒子推进器

摘要 先前给出了对粒子代码有用的精确动量更新。所涉及的表达是笨拙的。通过将动量视为 SU(2) × SU(2) 而不是 SO(3,1) 的表示，可以获得精确动量更新的更紧凑的表达式。可以制定时间步长的扩展，以便精确保留不变性，并获得与标准鲍里斯推动器相当的推动率。