非正交测量下的量子失谐量的研究

We shall investigate the quantum correlation measure of quantum discord under the POVM measurements. By using the picture of steering ellipsoid, we shall give an systemic method to calculate more optimal quantum discord for x-state under the non-orthogonal POVM measurements. Meanwhile, we shall try to find the invariant set of optimal components for the class of states having the same steering ellipsoid. This work may be helpful to find an analytic calculation approach for quantum discord. Furthermore, by employing the more optimal measure, we reinvestigate the sudden transition from classical to quantum decoherence regime, and give some criterions to determine wherther the sudden transition occurs.At last， we shall link the quantum discord with the Holevo quantity, and investigate further the possibility that the non entangled states with quantum correlations may be useful resources for quantum teleportation.

引入POVM测量意义下的量子失谐量, 通过操控椭球的几何描述, 结合熵函数的凹凸性, 系统的给出对于x-型态在POVM测量下量子失谐量的解析与数值计算办法.同时,试图借助操控椭球,针对一个固定的椭球, 找到系综分解方式的某些固定模式集合.这或许对于解析求解量子失谐量有一定的帮助和借鉴. 进一步的,利用POVM测量下给出的更优的量子失谐量,对量子与经典退相干之间的突变问题进行研究,系统的分析突变发生与否的条件.5最后, 试图建立量子失谐量与Holevo量之间的联系, 并且对存在量子关联的非纠缠态作为量子通讯资源的可行性进行研究.

引入POVM测量意义下的量子失谐量, 通过操控椭球的几何描述, 结合熵函数的凹凸性, 系统的给出对于x-型态在POVM测量下量子失谐量的解析与数值计算办法.同时,借助操控椭球,针对一个固定的椭球, 找到了系综分解方式的某些固定模式集合.这或许对于解析求解量子失谐量有一定的帮助和借鉴. 进一步的,利用POVM测量下给出的更优的量子失谐量,对量子与经典退相干之间的突变问题进行研究,系统的分析了突变发生与否的条件. 尤其是在退相位的情况, 分析了量子和经典关联的突变情况, 给出了在何种X形式的混态情况下, 会发生突变的条件.