Robust twin-field quantum key distribution through sending or not sending  

作　　者：Cong Jiang Zong-Wen Yu Xiao-Long Hu Xiang-Bin Wang 

机构地区：[1]Jinan Institute of Quantum Technology,Jinan 250101,China [2]State Key Laboratory of Low Dimensional Quantum Physics,Department of Physics,Tsinghua University,Beijing 100084,China [3]Data Communication Science and Technology Research Institute,Beijing 100191,China [4]School of Physics,State Key Laboratory of Optoelectronic Materials and Technologies,Sun Yat-sen University,Guangzhou 510275,China [5]Shanghai Branch,CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics,University of Science and Technology of China,Shanghai 201315,China [6]Shenzhen Institute for Quantum Science and Engineering,and Physics Department,Southern University of Science and Technology,Shenzhen 518055,China [7]Frontier Science Center for Quantum Information,Beijing 100084,China

出　　处：《National Science Review》2023年第4期71-80,共10页国家科学评论（英文版）

基　　金：the Ministry of Science and Technology of China through National Key Research and Development Program of China(2020YFA0309701);National Natural Science Foundation of China(12174215,12104184,11774198and 11974204);Shandong Provincial Natural Science Foundation(ZR2021LLZ007);Key R&D Plan of Shandong Province(2021ZDPT01);Open Research Fund Program of the State Key Laboratory of Low-Dimensional Quantum Physics(KF202110)。

摘　　要：The sending-or-not-sending(SNS)protocol is one of the most major variants of the twin-field(TF)quantum key distribution(QKD)protocol and has been realized in a 511-km field fiber,the farthest field experiment to date.In practice,however,all decoy-state methods have unavoidable source errors,and the source errors may be non-random,which compromises the security condition of the existing TF-QKD protocols.In this study,we present a general approach for efficiently calculating the SNS protocol's secure key rate with source errors,by establishing the equivalent protocols through virtual atenuation and the tagged model.This makes the first result for TF QKD in practice where source intensity cannot be controlled exactly.Our method can be combined with the two-way classical communication method such as active odd-parity pairing to further improve the key rate.The numerical results show that if the intensity error is within a few percent,the key rate and secure distance only decrease marginally.The key rate of the recent SNS experiment in the 511-km field fiber is still positive using our method presented here,even if there is a±9.5%intensity fluctuation.This shows that the SNS protocol is robust against source errors.

关 键 词：quantum information quantum key distribution sending or not sending twin field source error 

分 类 号：O413[理学—理论物理] TN918.4[理学—物理]