DepartmentofMathematics;
CapitalNormalUniversity;
Beijing100037;
China;
InstituteofAppliedMathematics;
universityofBonn;
53115Bonn;
Germany;
DepartmentofMathematics;
CapitalNormalUniversity;
Beijing100037;
China;
量子态; 可分离性; 量子纠缠; 密度矩阵; 秩; 量子系统;