基于非对称量子信道的非局域N-qubit受控幺正门的网络设计与优化

发布时间：2018-08-25 12:40

【摘要】：本文提出在非对称量子信道辅助下有效地实现非局域N-qubit受控幺正门的局域操作方案.分别设计两个量子网络去实现该非局域门.方案一用(N 2)个对称的qubit-qubit Bell态和一个非对称的qubit-qudit Bell态作为量子信道.它利用qubit-qudit Bell态中qudit的(N 2)个附加能级将(N 1)个非局域控制态的多个计算基态"隐藏"起来,简化了该非局域门的操作.该方案的缺陷是,qudit的能级和所耗费的1-qudit门随N增加.在不改变网络功能的条件下,方案二用(N 1)个非对称的qubit-qutrit Bell态作为量子信道,对方案一进行了优化.该方案分别利用(N 1)个qutrit的第3能级仅将(N 1)个非局域控制态的某个计算基态"暴露"于随后的操作,进一步降低了网络的复杂度,提高了操控速度.值得注意的是,两个方案在不使用辅助系统的条件下所需的局域二体门仅为(3N 4)个.
[Abstract]:This paper presents an effective local operation scheme for nonlocal N-qubit controlled unitary gate assisted by asymmetric quantum channels. Two quantum networks are designed to realize the nonlocal gate. Scheme 1 uses (N ~ 2) symmetric qubit-qubit Bell states and an asymmetric qubit-qudit Bell state as quantum channels. It uses the (N ~ 2) additional energy levels of qudit in the qubit-qudit Bell state to "hide" a number of computational ground states of (N ~ 1) nonlocally controlled states, which simplifies the operation of the nonlocal gate. The defect of this scheme is that the energy level of Qudit and the cost of 1-qudit gate increase with N. Under the condition that the network function is not changed, scheme 1 is optimized by using (N + 1) asymmetric qubit-qutrit Bell states as quantum channels. In this scheme, the third level of (N + 1) qutrit is used to "expose" only a computational ground state of (N ~ (1) nonlocally controlled states to subsequent operations, which further reduces the complexity of the network and improves the control speed. It is worth noting that only (3N) 4 local two-body gates are required for the two schemes without the use of the auxiliary system.
【作者单位】：佛山科学技术学院光电子与物理学系;
【基金】：广东省自然科学基金(编号:06029431)资助
【分类号】：O413;TP38

【相似文献】