三能级原子同时存在辐射和吸收时的量子相干性  

Coherence properties of radiation and absorption in the three-level atom

作　　者：高峰[1] 张登玉[1] 唐美娟[1] 

机构地区：[1]衡阳师范学院物理系

出　　处：《量子电子学报》2007年第4期456-462,共7页Chinese Journal of Quantum Electronics

基　　金：湖南省自然科学基金(06JJ50118);湖南省教育厅重点科研基金(04A006)

摘　　要：量子位和环境的相互作用,将引起量子位能量耗散或相对位相改变,最终导致量子位由相干叠加态退化为混合态或纯态,这种现象被称为量子消相干。针对三能级原子同时存在辐射和吸收时的情况,基于量子力学和Kraus算子理论,利用约化密度矩阵方法,分析了三能级原子密度矩阵元的演化规律,从而研究该系统的量子相干特性。结果表明:初态处于相干叠加态的三能级原子,由于辐射和吸收,可能演化成相干叠加态、未完全混合态、完全混合态、纯态。The interaction of the qubit with its environment induces the qubit dissipation or dephasing, which causes the qubit collapse from a coherent superposition state to a mixed or pure state. This process is known as quantum decoherence. The radiation and absorption of the three-level atom is studied. Basis on theories of quantum mechanics and Kraus operator and utilizing the reducible density rectangular method the transformation of density matrix of the three-level atom which simultaneously in the case of the radiation and absorption is investigated. The coherence properties of quantum states are also investigated. If the early state of the three-level atom is coherence state, it may evolve to the coherent state, the partial mixed state completely, the completely state, and the pure state.

关 键 词：量子光学 Kraus算子 量子相干 三能级原子 

分 类 号：O431[机械工程—光学工程]