【摘要】 考虑量子信道对多体纠缠鲁棒性的影响.先根据可分态之集为一个凸闭集,证明可以取到纠缠鲁棒性定义中的下确界,再证明同一纠缠态ρ的两个最优态的凸组合仍是最优态,纠缠鲁棒性作为定义态集合上函数是下半连续的;最后,分别给出一个量子信道不增加、不减少及保持所有量子态的纠缠鲁棒性的充分必要条件.更多还原

【Abstract】 We considered influences of quantum channels on robustness of multi-body entanglement.Firstly,we proved that the infimum in the definition of the robustness of entanglement(RoE)could be attained based on the fact that the set of all separable states was a convex closed set.Secondly,we proved that a convex combination of two different optimal states of the same entanglement stateρwas still the optimal state,and the RoE was a lower semi-continuous function on the set of all quantum states.Finally,we gave necessary and sufficient conditions for the RoE of a quantum channel,which did not increase,did not reduce and maintained all quantum states.更多还原