Progress towards practical device-independent quantum key distribution with spontaneous parametric down-conversion sources, on-off photodetectors, and entanglement swapping
Progress towards practical device-independent quantum key distribution with spontaneous parametric down-conversion sources, on-off photodetectors, and entanglement swapping
复制标题
利用自发参数下转换源、开关光电探测器和纠缠交换实现实用的独立于设备的量子密钥分配的进展
DOI：
10.1103/physreva.93.042328
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发表时间：
2015
影响因子：
2.9
通讯作者：
M. Sasaki
中科院分区：
文献类型：
--
作者：
K. Seshadreesan;M. Takeoka;M. Sasaki
设备无关的量子密钥分发（DIQKD）保证了密钥的无条件安全性，而无需对所使用的设备的内部工作原理进行假设。在实践中实现DIQKD的主要挑战是检测漏洞问题，这是固有的光子测试贝尔不等式在有损信道。我们重新审视Curty和Moroder [Phys.Rev.A84，010304（R）（2011）]的提议，使用基于线性光学的纠缠交换中继（ESR）来解决这个问题。我们考虑纠缠源和光电探测器的现实模型;更准确地说，（a）基于脉冲自发参量下转换（SPDC）源的偏振纠缠态，具有无限高阶多光子分量和多模光谱结构，以及（B）具有非单位效率和非零暗计数概率的开关光电探测器。我们的研究结果表明，不完美的ESR为基础的计划仍然使积极的关键率在距离远大于什么是可能的没有ESR足够大的检测器和耦合效率，小暗计数概率的检测器和小的频谱扩展的来源。
Device-independent quantum key distribution (DIQKD) guarantees unconditional security of secret key without making assumptions about the internal workings of the devices used. The primary challenge in realizing DIQKD in practice is the detection loophole problem that is inherent to photonic tests of Bell's inequalities over lossy channels. We revisit the proposal of Curty and Moroder [Phys. Rev. A 84, 010304(R) (2011)] to use a linear optics-based entanglement-swapping relay (ESR) to counter this problem. We consider realistic models for the entanglement sources and photodetectors; more precisely, (a) polarization-entangled states based on pulsed spontaneous parametric downconversion (SPDC) sources with infinitely higher order multi-photon components and multimode spectral structure, and (b) on-off photodetectors with non-unit efficiencies and non-zero dark count probabilities. Our results show that the imperfect ESR-based scheme still enables positive key rates at distances much larger than what is possible without ESR for sufficiently large detector and coupling efficiencies, small dark count probabilities in the detectors and small spectral spread in the sources.