压缩相干态光场与Λ型三能级原子相互作用的纠缠特性

利用量子熵理论,研究了压缩相干态光场与Λ型三能级原子的量子纠缠随时间的演化特性.结果表明：光场与原子纠缠度依赖于初态原子能级叠加系数、光场压缩参量、相干态振幅参量及失谐量与耦合系数之比.当光场压缩参量增大时,光场与原子的最大纠缠度增大;若场失谐量与耦合系数之比增大,光场与原子纠缠则呈现周期性演化,系统呈现接近退纠缠;若场失谐量与耦合系数之比增大,光场与原子纠缠呈现周期性,场失谐量与耦合系数的比值足够大时,在一定时刻系统可处于稳定的最大纠缠态,且系统演化呈现周期性.

Quantum Entanglement of the Squeezed Coherent State Interacting with a Λ-type Three-level Atom

Quantum entanglement between a squeezed coherent state and a Λ type three level atom was studied via quantum entropy theory.The results show that the maximal degree of entanglement depends on the initial state parameters of the atom,squeezing factor,coherent amplitude factor,and the ratio of detuning to coupling constant.The entanglement strengthens with the increasing of squeezing factor of light.The entanglement occurs periodic evolution with the increasing of the ratio of detuning to coupling constant,the system appears disentanglement.When the ratio of detuning to coupling constant becomes larger,the entanglement between the field and atoms shows periodical change.The system appears steady and maximal entanglement state periodically as the ratio of detuning to coupling constant is sufficiently large.