两个三能级原子纠缠的可提纯性猝死

研究了两个全同V 型三能级原子在独立库中纠缠的可提纯性问题.在退相位通道中利用超算符求解出系统的时间演化密度矩阵,在特定的初态条件下得到了系统的负本征值.用负度和重排密度矩阵的迹范数量度了系统可提纯性的演化规律.结果表明：可提纯性保持的时间受参数α 的影响,α 越大,可提纯性保持的时间就越长,但纠缠的可提纯性还是会衰减并最终消失;对于负度不可量度的情况,使用重排密度矩阵的迹范数进一步加以研究,分析了整个范围内的时间演化规律,绘出了其演化曲线,并作了相应的物理解释;得到了在退相位通道中可提纯性会出现猝死的结论.

Distillability of Entanglement Sudden Death in Qutrit-Qutrit Systems

By studying the distillability of entanglement in qutrit-qutrit systems, each of whixh is interacted with its separable reservoir. By using the superoperator method, the time evolution of the densitymatrix of system is solve in the dephasing noise. Under the condition of special initial states, thenegative eigenvalues of the system is obtained. The evolution regulation of distillability is measured bynegativity and the trace norm of realigning density matrix. The result shows that the distillability isaffected by the parameter α. The long preserving time corresponds with the bigger α value, but thedistillability of entanglement still decays and disappears finally. In the situation when negativity is notsuitable to measure distillability, we use the trace norm of realigning density matrix to reachdistillability in a step, get the time evolution regulation in the total regime. The evolution curves can bedrawn, and the corresponding physical explanation is given. The conclusion of distillability suddendeath in dephasing noise is testified in this paper.