Memory-assisted quantum key distribution resilient against multiple-excitation effects
Memory-assisted quantum key distribution resilient against multiple-excitation effects
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DOI：
10.1088/2058-9565/aa9cfb
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发表时间：
2017-07
影响因子：
6.7
通讯作者：
Nicolo Lo Piparo;N. Sinclair;M. Razavi
中科院分区：
文献类型：
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作者：
Nicolo Lo Piparo;N. Sinclair;M. Razavi
存储器辅助的测量设备无关的量子密钥分配（MA-MDI-QKD）最近被提出作为通过使用现有的或接近可实现的量子技术来改善QKD系统的速率-距离行为的技术。MA-MDI-QKD的承诺是，与概率量子中继器所需的量子存储器相比，它需要的量子存储器要求更低。然而，早期的研究表明，为了击败传统的无记忆QKD方案，MA-MDI-QKD协议中使用的量子存储器必须具有高带宽存储积和短的交互时间。在不同类型的量子存储器中，基于集成的存储器提供了一些所需的规格，但它们通常会受到多重激发效应的影响。为了避免后一个问题，在本文中，我们提出了两个新的变体的MA-MDI-QKD都依赖于单光子源纠缠的目的。一种是基于量子中继器中的纠缠分布的已知技术。即使使用理想的单光子源，这种方案也没有任何优势。通过找到问题的根本原因，我们提出了另一种设置，即使我们允许单光子源中的一些缺陷，它也可以优于单无记忆设置。对于这样一个计划，我们比较了不同类型的集成为基础的内存的关键率，并表明某些类的原子集成可以提高率与距离的行为。
Memory-assisted measurement-device-independent quantum key distribution (MA-MDI-QKD) has recently been proposed as a technique to improve the rate-versus-distance behavior of QKD systems by using existing, or nearly-achievable, quantum technologies. The promise is that MA-MDI-QKD would require less demanding quantum memories than the ones needed for probabilistic quantum repeaters. Nevertheless, early investigations suggest that, in order to beat the conventional memory-less QKD schemes, the quantum memories used in the MA-MDI-QKD protocols must have high bandwidth-storage products and short interaction times. Among different types of quantum memories, ensemble-based memories offer some of the required specifications, but they typically suffer from multiple excitation effects. To avoid the latter issue, in this paper, we propose two new variants of MA-MDI-QKD both relying on single-photon sources for entangling purposes. One is based on known techniques for entanglement distribution in quantum repeaters. This scheme turns out to offer no advantage even if one uses ideal single-photon sources. By finding the root cause of the problem, we then propose another setup, which can outperform single memory-less setups even if we allow for some imperfections in our single-photon sources. For such a scheme, we compare the key rate for different types of ensemble-based memories and show that certain classes of atomic ensembles can improve the rate-versus-distance behavior.