研究两个全同二能级原子与单模场相互作用的Tavis-Cummings模型中的量子纠缠在场和两原子初始分别为真空场和纠缠或非纠缠状态下，得出体系状态将演化为三体近似w纠缠态通过对纠缠量的计算得出：该三体近似w纠缠态纠缠量的演化特性将随三体所处的初始状态、原子司及原子与场司的耦合系数、失谐程度、原子反转粒子数的变化而变化值得一提的是可得出原子司耦合作用强度对纠缠量的非线性效应，并且纠缠量展现出与原子反转粒子数一致的周期振荡现象

在两个定态全同二能级原子与单模光场共振相互作用的Tavis Cummings模型中，原子与场间相互作用与原子间相互作用相差较大时，体系可产生三比特完全纠缠态。通过分析得出，该体系的三比特纠缠随二原子和单模场所处的初始叠加状态、二原子间及原子与光场间的耦合系数的变化而变化。特别地，在特定的初始状态下，该体系可产生w纠缠态，而产生w纠缠态的必要条件是原子之间的耦合要比原子与场之间的耦合小得多。

We consider the spontaneous emission of a broadening molecule on the surface of a micro-sphere in this paper. The density of states for the micro-cavity is derived from quasi-normal models(QNM's) expansion of the correlation functions of electromagnetic fields. Through detailed analysis we show that only weak coupling between a broadening atom(molecule) and the electromagnetic fields exists in a dielectric sphere cavity whether the sphere is small or big. From these results we find the explicit expression of the spontaneous emission decay rate for a surfactant broadening molecule on the surface of a micro-droplet with radius a, in which only 1/a and 1/a2 components exhibit. Then we apply this expression to a real experiment and obtain a consistent result with the experiment. We also show that the real-cavity model of local field correction is accurate, and reveal that the local-field correction factor can be measured precisely and easily by fluorescence experiments of surfactant molecules. Moreover, the spontaneous decay of a surfactant molecular on droplet's surface is sensitive to the atomic broadening, so that the fluorescence experiment in a micro-sphere cavity can be used to estimate the radiative broadening.

研究了两个纠缠的两能级原子与单模粒子数场进行相互作用系统中两原子的纠缠演化. 结果表明：两个原子之间的纠缠呈现出周期性的演化特性，初始两原子的状态、原子之间的偶极相互作用和粒子数场对腔中两个原子的纠缠有着显著的影响. 发现适当选择原子的实态，两原子会永远处于最大纠缠态.

通过求解系统的Milburn方程，研究了两能级原子与双模SU(1,1)相干态光场发生相互作用系统中，原子与场的纠缠及双模SU(1,1)相干态场的模间纠缠随时间的演化问题，讨论了内禀退相干、双模光子数差等对纠缠度的影响．结果表明，存在内禀退相干时，随着时间的演化，场．原子纠缠逐渐减小到一个确定值，而模间纠缠逐渐增大到一个确定值，两者演化的最终值只取决于双模光子数差和平均光子数，而与内禀退相干因子无关．

We explicitly present a scheme for quantum state sharing of an arbitrary multiqubit state using nonmaximally entangled GHZ states as the quantum channel and generalized Bell states as the measurement basis. The scheme succeeds only probabilistically with its total success probability depending on the degree of entanglement matching between the quantum channel and the generalized Bell states. Security of the scheme is guaranteed by the fact that attacks of an outside eavesdropper or/and an inside dishonest party will inevitably introduce detectable errors.

We construct a genuine (2N+1)-qubit entangled state to perform controlled teleportation of an arbitrary N-qubit state. The constructed state is a complementarity to the genuine 2N-qubit entangled state constructed by Yeo and Chua for N=2[Phys. Rev. Lett. 96, 060502(2006)] and by Chen, Zhu, and Guo for any N [ Phys. Rev. A 74, 032324(2006)]. We also quantify the entanglement of the state and classify it with the well-known GHZ and W states by means of the recently proposed generalized global entanglement and the associated auxiliary measures [ Phys. Rev. A 74, 022314 (2006)}. Our study is of general importance with respect to exploring and exploiting the genuine multiqubit entanglement.

通过求解系统的Milbtim方程，研究了两个二能级原子和单模场相互作用系统中原子间纠缠和贝尔不等式破坏随时间的演化特性，讨论了偶极相互作用、场与原子的失谐量对纠缠度以及贝尔不等式破坏的影响．结果表明：原子间偶极．偶极相互作用对纠缠度和贝尔不等式破坏有显著影响，失谐量增大会使两原子的纠缠度和贝尔不等式破坏变大，并且两原子所能达到稳定的纠缠受偶极相互作用系数与失谐量两者之差的影响．同时还发现两原子的纠缠与贝尔不等式破坏并不是单调的函数关系，很小的纠缠也可以产生贝尔不等式破坏．

考虑双模纠缠相于光场，将其中一束光场注入腔中与一个二能级原子发生共振相互作用，总系统在腔量子电动力学演化过程中，对原子作选择性的测量，通过操纵参加相互作用的时间以及选择适当的光场参量可控制未参加相互作用光场的量子统计性质，在一定条件下可产生反聚束、压缩态等非经典光场，并且通过适当的控制和调整这些参量可以改变未参加相互作用光场的反聚束和压缩特性的强弱。这样，通过利用腔与原子之间简单的共振相互作用和相干光场之间的纠缠关联，实现了远程的、无直接量子测量的控制或改变相干光场的非经典性质这一目的。

通过引入正交基矢，连续变量形式的纠缠相干态转化成分立形式，然后用concurrence 方法计算了纠缠度，同时研究了其非经典效应（压缩效应，反聚束效应）. 发现纠缠总是伴随着压缩效应和反聚束效应两者之一，并随相应非经典 效应的增大而增大。