量子光学学报, 2016, 22 (4): 303, 网络出版: 2016-12-09
随时间变化磁场中自旋演化的求解新方法
A New Approach to Spin Evolution in Time-Dependent Magnetic Field
自旋粒子 Schwinger表象 含时规范变换 自旋演化 spin particle schwinger representation gauge transformation spin evolution
摘要
采用粒子自旋角动量的两个独立谐振子实现和含时规范变换方法,得到不同空间位形的时变磁场中粒子的自旋态,并指出作旋转波近似,即忽略含时快变反共振项的物理原因。本文所用的新方法可应用于其它一些量子系统。
Abstract
A spin particle subjected to time-dependent magnetic field is reseached in detail at different magnetic field configurations.A spin state is obtained easily by means of realizing two independent harmonic oscillators for spin angular momentum and a gauge transformation method,and physical reason for rotationless wave approximation,i.e. ignoring time-varying anti-resonant term is clarified.The approach can also be applicable in some other quantum systems.
杨进, 林能杰, 张德培, 石宇鹏. 随时间变化磁场中自旋演化的求解新方法[J]. 量子光学学报, 2016, 22(4): 303. YANG Jin, LIN Neng-jie, ZHANG De-pei, SHI Yu-peng. A New Approach to Spin Evolution in Time-Dependent Magnetic Field[J]. Acta Sinica Quantum Optica, 2016, 22(4): 303.