变耦合系数的简并拉曼耦合J-C模型中场熵的演化

研究了考虑耦合系数随时间线形变化的简并拉曼耦合J-C模型中场熵随时间演化特性,分析了耦合系数变化的快慢和不同的初始光场对场熵的影响。结果表明:(1)无论光场初始态如何,场熵均呈周期性演化,平均光子数n-的增加并不改变场熵演化周期的大小;(2)初始光场统计性质的不同对最大场熵值和最大场熵值变化的幅度产生较大的影响;(3)线形调制使场熵呈现的完美周期性振荡遭到破坏。当原子-场耦合系数变化缓慢时,原子进入统计混合态的速度被减缓;而当原子-场耦合系数变化较快时,则不仅使场熵演化曲线的振荡周期逐渐减小、振荡频率越来越快,而且使原子与场退纠缠的时刻增多。

Evolution of the Field Entropy in Degenerate Raman Coupling Jaynes-Cummings Models with a Time-Dependent Atom-Field Coupling

The property of the field entropy in degenerate Raman coupling Jaynes-Jummings models with a linear time-dependent atom-field coupling is investigated. The influence of different initial field and time-dependent atomfield coupling coefficient on the field entropy is discussed at length. The results show that:(1)All the evolutions of field entropies have periodicity whatever the initial field states are. The increase of the mean number of photon does not change evolution periodicity;(2)The different statistical properties of the initial fields will give great effects on the values of the maximum field entropy and the variational range the highest value of field entropy;(3)the perfect periodicity of field entropy will be destroyed due to the linear modulation. When the atom-field coupling coefficient changes slowly,the speed of atoms' entering the statistical state is slowered;when the atom-field coupling coefficient changes rapidly,the oscillating periodicity of the curve of the evolution of field entropy is shortened,the oscillating frequency of the evolution of field entropy is fastened,and the moments of the atom-field disentanglement are manifolded.