论文部分内容阅读
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.
In this paper, a local operation scheme of non-local N-qubit controlled unitary gate is proposed, which is effectively supported by asymmetric quantum channel. Two quantum networks are designed to realize the non-local gate. Symmetric qubit-qubit Bell states and an asymmetric qubit-qudit Bell state as quantum channels, using the (N-2) additional energy levels of qudit in the qubit-qudit Bell state to combine (N-1) The multi-state ground state “hidden” simplifies the operation of this non-local gate. The drawback of this scheme is that the qudit level and the 1-qudit gate consumed increase with N. Without changing (N-1) asymmetric qubit-qutrit Bell states are used as the quantum channel in Scheme 2 to optimize the scheme I. This scheme uses the (N-1) qutrit third level Only one of the (N-1) nonlocal state-of-states calculations ground state “exposes” to subsequent operations, further reducing the complexity of the network and increasing the speed of manipulation. It is worth noting that both schemes are Without the use of auxiliary systems, the number of local two-body gates required is only (3N-4).