原子与频率随时间变化场相互作用系统中场熵的演化

Evolution of Field Entropy with a Time-varing Frequency in the Multiphoton Jaynes-Cummings Model

利用多光子Jaynes-Cummings模型,考虑场频率随时间以正弦函数形式作小量变化,在旋波近似下,研究了二能级原子通过多光子跃迁与单模辐射场相互作用系统中场熵的演化规律.利用数值计算方法给出场熵随时间的演化曲线.研究结果表明:场熵的演化受场频率随时间正弦函数形式变化的调制,场频率振荡的幅值u越大调制作用越强,在场频率振荡的幅值u大于一定值后,场熵将按场频率周期性的变化规律作周期性振荡.

By using the multiphoton Jaynes-Cummings model, the dynamical properties of the field entropy in the system that consists of a two-level atom interacting with a single-mode field via multiphoton transition are studied. The frequency of the field varying with time in the form of u sin wt has been considered. The results show that the time-evolution behavior of the field entropy is modulated by the frequency variation of field using the numerical. The modulation intensity is enchanced as the amplitude u of frequency variation of field increases. When the amplitude u of the time varying fields is larger than a fixed value,the time-evolution behavior of the field entropy will display periodic oscillation behavior. Its oscillation period agrees with the period of frequency varying. It shows that the evolution of field entropy is influenced by the frequency parameters w and u of the field varying with time.