Experimental quantum key distribution beyond the repeaterless secret key capacity
Experimental quantum key distribution beyond the repeaterless secret key capacity
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DOI：
10.1038/s41566-019-0377-7
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发表时间：
2019-05-01
期刊：
影响因子：
35
通讯作者：
Shields, A. J.
中科院分区：
文献类型：
--
作者：
Minder, M.;Pittaluga, M.;Shields, A. J.
量子通信有望彻底改变信息交换和保护的方式。与传统的对应物不同，它们基于微弱的光脉冲，无法通过传统的光中继器放大。因此，它们受到传播信道损耗的严重损害，将其传输速率和范围限制在称为无中继密钥容量的理论极限以下。人们认为用当今的技术克服这一限制是不可能的，直到最近提出了一种使用相位相干光信号和辅助测量站来分发量子信息的方案。在这里，我们首次通过实验证明了这种方案，并且通道损耗显着，超过 90 dB。在高丢失情况下，产生的安全密钥率超过了无中继密钥容量，这是以前从未达到过的结果。这是推动量子通信成为当今世界可靠资源的重要一步。
Quantum communications promise to revolutionize the way information is exchanged and protected. Unlike their classical counterpart, they are based on dim optical pulses that cannot be amplified by conventional optical repeaters. Consequently, they are heavily impaired by propagation channel losses, confining their transmission rate and range below a theoretical limit known as repeaterless secret key capacity. Overcoming this limit with today's technology was believed to be impossible until the recent proposal of a scheme that uses phase-coherent optical signals and an auxiliary measuring station to distribute quantum information. Here, we experimentally demonstrate such a scheme for the first time and over significant channel losses, in excess of 90 dB. In the high loss regime, the resulting secure key rate exceeds the repeaterless secret key capacity, a result never achieved before. This represents a major step in promoting quantum communications as a dependable resource in today's world.