论文标题
量子网络中以距离独立的速率产生纠缠
Entanglement generation in a quantum network at distance-independent rate
论文作者
论文摘要
我们在量子互联网上开发了纠缠生成协议,该协议允许重复器节点使用$ n $ qubit的greenberger-horne-zeilinger(GHz)投影测量值,可以将$ n $ n $成功地融合为成功的{\ em links},即,在$ n $ n网络上共享$ n $ network edge at n node node node node node node node。在固态Qubit记忆中,实施$ n $ - 融合,以$ n \ ge 3 $的价格实施$ n $ fusion,对$ n \ ge 3 $的实施不比2美元(贝尔 - 巴斯的测量值)要困难得多。如果我们在节点上甚至允许$ 3 $ - fe,我们会发现 - - 通过与位点键入渗透问题的修改版本建立联系 - 尽管有损失(因此)链接级别的生成(因此)链接级别的产生,并且在节点上的融合度测量值的融合成功率可能会产生最初的距离和鲍尔之间的距离,并且在bob之间的距离不断增长。我们证明,这种强大的网络属性无法使用任何具有钟声测量和多重构建的量子网络协议来实现。我们还设计了一个两方量子密钥分布协议,该协议将两个节点之间共享的纠缠状态转换为一个共享的秘密,其关键生成速率与双方之间的距离无关。
We develop a protocol for entanglement generation in the quantum internet that allows a repeater node to use $n$-qubit Greenberger-Horne-Zeilinger (GHZ) projective measurements that can fuse $n$ successfully-entangled {\em links}, i.e., two-qubit entangled Bell pairs shared across $n$ network edges, incident at that node. Implementing $n$-fusion, for $n \ge 3$, is in principle not much harder than $2$-fusions (Bell-basis measurements) in solid-state qubit memories. If we allow even $3$-fusions at the nodes, we find---by developing a connection to a modified version of the site-bond percolation problem---that despite lossy (hence probabilistic) link-level entanglement generation, and probabilistic success of the fusion measurements at nodes, one can generate entanglement between end parties Alice and Bob at a rate that stays constant as the distance between them increases. We prove that this powerful network property is not possible to attain with any quantum networking protocol built with Bell measurements and multiplexing alone. We also design a two-party quantum key distribution protocol that converts the entangled states shared between two nodes into a shared secret, at a key generation rate that is independent of the distance between the two parties.