By using a coherent state method,we prove that the geometric phase of the spinor in rotating magnetic fields to be one half of the solid angle that the spinor states sweep.

• 运用相干态方法，本文证明了中子在旋转磁场中的几何相位是粒子态矢量在态空间中扫过的立体角的一半，同时提供了一种几何相位在周期演化中的简单算法。