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arXiv · 1904.07074

Optimized protocol for twin-field quantum key distribution

Rong Wang·Zhen-Qiang Yin·Feng-Yu Lu·Shuang Wang·Wei Chen·Chun-Mei Zhang·Wei Huang·Bing-Jie Xu·Guang-Can Guo·Zheng-Fu Han
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Abstract

Twin-field quantum key distribution (TF-QKD) and its variant protocols are highly attractive due to the advantage of overcoming the rate-loss limit for secret key rates of point-to-point QKD protocols. For variations of TF-QKD, the key point to ensure security is switching randomly between a code mode and a test mode. Among all TF-QKD protocols, their code modes are very different, e.g. modulating continuous phases, modulating only two opposite phases, and sending or not sending signal pulses. Here we show that, by discretizing the number of global phases in the code mode, we can give a unified view on the first two types of TF-QKD protocols, and demonstrate that increasing the number of discrete phases extends the achievable distance, and as a trade-off, lowers the secret key rate at short distances due to the phase post-selection.

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Rong Wang, Zhen-Qiang Yin, Feng-Yu Lu, Shuang Wang, Wei Chen, Chun-Mei Zhang, Wei Huang, Bing-Jie Xu, Guang-Can Guo, Zheng-Fu Han. 2019-04-15. Optimized protocol for twin-field quantum key distribution. https://doi.org/10.1038/s42005-020-00415-0

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