Λ型三能级原子与数态单模光场互作用系统的纠缠特性  

Entanglement of a Λ-type three-level atom with a single-mode field initially in the number state

作　　者：周青春[1,2] 祝世宁[1] 

机构地区：[1]南京大学物理系,固体微结构国家重点实验室,南京210093 [2]华东船舶工业学院数理系

出　　处：《物理学报》2005年第5期2043-2048,共6页Acta Physica Sinica

基　　金：国家自然科学基金 (批准号 :90 2 0 10 0 8)资助的课题 .~~

摘　　要：通过计算场的量子力学熵讨论了Λ型三能级原子与数态单模光场互作用系统的纠缠和退纠缠时间演化规律 .结果表明 ,系统的纠缠呈现周期性 ,最大纠缠度依赖于原子初态、初始场光子数及场失谐量与耦合系数之比 .一周期内出现最大纠缠和退纠缠的次数与初始场光子数无关 .近简并下能级初始相对位相影响场熵演化 ,而激发态和基态之间的初始相对位相对场熵演化无影响 .The time evolution of entanglement and disentanglement between a Λ-type three-level atom and a single-mode field initially in the number state in an ideal cavity are investigated by considering von Neumann entropy of the optical field. Results indicate that entanglement of the system displays periodicity; the maximal degree of entanglement depends on the initial atomic state, the initial photon number and the ratio of detuning to the coupling constant, while the number of times for maximal entanglement and disentanglement in a period is independent of the initial photon number. The initial relative phase between the two lower states have effects on the time evolution of field entropy, while the initial relative phases between the excited state and the ground states of the atom does not.

关 键 词：三能级原子 数态单模光场 量子纠缠 冯诺伊曼熵 激发态 

分 类 号：O562[理学—原子与分子物理]