Practical figures of merit and thresholds for entanglement distribution in quantum networks
Practical figures of merit and thresholds for entanglement distribution in quantum networks
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DOI：
10.1103/physrevresearch.1.023032
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发表时间：
2019-09-27
影响因子：
4.2
通讯作者：
Dowling, Jonathan P.
中科院分区：
文献类型：
--
作者：
Khatri, Sumeet;Matyas, Corey T.;Dowling, Jonathan P.
在全球规模的量子网络开始运行之前，重要的是要考虑如何评估它们的性能，以便它们可以被构建以实现所需的性能。我们提出了量子网络性能的两个实用指标：平均连接时间和平均最大纠缠簇大小。这些量基于量子网络中基本链路的生成，这是在实现任何远程纠缠分发之前必须满足的关键初始要求，并且在当前实现中具有固有的概率性。我们得到的界限，这些数字的品质为一类特定的量子中继器协议组成的重复，直到成功的基本链路生成，然后在中间节点加入测量，延长纠缠范围。我们的研究结果导致对量子存储器相干时间的要求，对中继器链长度的要求，以超过无中继器速率限制，以及对量子网络实现的其他方面的要求。这些要求完全基于量子网络中基本链路生成的固有概率性质，并且它们适用于具有任意拓扑结构的网络。
Before global-scale quantum networks become operational, it is important to consider how to evaluate their performance so that they can be built to achieve the desired performance. We propose two practical figures of merit for the performance of a quantum network: the average connection time and the average largest entanglement cluster size. These quantities are based on the generation of elementary links in a quantum network, which is a crucial initial requirement that must be met before any long-range entanglement distribution can be achieved and is inherently probabilistic with current implementations. We obtain bounds on these figures of merit for a particular class of quantum repeater protocols consisting of repeat-until-success elementary link generation followed by joining measurements at intermediate nodes that extend the entanglement range. Our results lead to requirements on quantum memory coherence times, requirements on repeater chain lengths in order to surpass the repeaterless rate limit, and requirements on other aspects of quantum network implementations. These requirements are based solely on the inherently probabilistic nature of elementary link generation in quantum networks, and they apply to networks with arbitrary topology.