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Long Distance Quantum Key Distribution

Speaker: Lai Zhou Beijing Academy of Quantum Information Sciences
Time: 2023-04-21 14:00-2023-04-21 15:00
Venue: MMW-S327


Quantum cryptography promises secure communication between two distant users. However, secure key rate of point-point quantum key distribution (QKD) is bounded by the linear rate-loss limit. Twin-field (TF) QKD can break this limit but its implementation requires global phase tracking and usually also cumbersome interferometric implementations, which are often impractical for network deployment. We remove the above shortcomings with two different solutions. In the first solution, we introduce locally generated frequency combs to stabilise an open channel, and develop a simple and versatile TF-QKD setup that does not need service fibre [1]. In the second, we implement a simple measurement device independent (MDI) QKD with post-measurement pairing technique. We demonstrate the capability of asynchronous MDI-QKD (also named mode-pairing MDI-QKD) overcoming the linear rate-loss limit without global phase tracking [2].

[1] L. Zhou, J. Lin, Y. Jing and Z.. Yuan, Nat. Commun. 14, 928 (2023).

[2] L. Zhou, J. Lin, Y. Xie, Y. Lu, Y. Jing, H. Yin and Z. Yuan, arXiv: 2212.14190 (2022), to appear in PRL.

Short Bio:

Dr. Lai Zhou received the B.S. and Ph.D. degrees from Tsinghua University in 2013 and 2018, respectively. He was a postdoctor at the University of Oxford in 2019. Since February 2020, he has been an assistant researcher at Beijing Academy of Quantum Information Sciences. His research interests include long distance quantum key distribution and quantum networks.