摘要
利用Von Neumann约化熵理论研究了多模相干态场与二能级原子非简并多光子相互作用系统中量子场熵的时间演化特性,得到了含有失谐量的多模场熵的解析表达式,并通过数值计算讨论了光场为三模场时频率失谐量对场熵演化的影响.结果发现:当近共振时,失谐量几乎不影响场与原子之间的纠缠特性;而当远离共振时,量子场熵很强地依赖于失谐量的大小,特别是当失谐量足够大时,场与原子几乎总是处于纠缠态.
The time evolution of the field quantum entropy in the system of a multi mode coherent field interacting with a two level atom through the non-degenerate multi photon process is investigated using the Von Neumann reduced entropy, the analytical expression of the multimode field entropy including the frequency detuning is obtained. The numerical results for the three mode field interacting with the atom are presented. The influence of the frequency detuning on the field quantum entropy is discussed. It is found that the frequency detuning has nearly no effect on the entanglement between the three-mode coherent field and the two-level atom when the field and the atom are near resonance, but the time evolution of the field quantum entropy is strongly dependent on the values of the frequency detuning when the field and the atom are far from resonance, especially when the frequency detuning is large enough, the field and the atom are nearly always in entangled states.
出处
《光子学报》
EI
CAS
CSCD
北大核心
2008年第5期1057-1062,共6页
Acta Photonica Sinica
基金
the Natural Science Foundation of Shaanxi Province under Grant No 2001SL04
the Science and Technology Key Task Foundation Item of Shaanxi Province under Grant No 2002K05-G9
关键词
量子光学
量子场熵
量子纠缠
非简并多光子
频率失谐
Quantum optics
Quantum field entropy
Quantum entanglement
Non-degenerate multi-photon
Frequency detuning
