摘要
经典相位匹配量子密钥分发要求信道对称,而实际应用中非对称信道应用场景更加普遍.为研究信道非对称性对相位匹配协议性能的影响,基于经典相位匹配协议框架提出非对称相位匹配协议,建立相关数学仿真模型,并对信道非对称情况下诱骗态和统计波动等对系统的影响进行仿真分析.结果表明:信道非对称性对系统性能影响巨大,随着信道衰减差异的增大系统性能减小,且减小速度逐渐加快,超过4 dB时已无法生成密钥;诱骗态方案不能改变系统对信道衰减差异的容忍度,但在信道衰减差异较大时,增加诱骗态可以显著提升系统性能;随着数据长度的增大,系统对信道衰减差异的容忍度逐渐提升,当数据长度大于10^(12)时,这种提升不再明显,与对称信道相比,当信道衰减差异为2 dB时,随着数据长度的增大,系统性能提升更加明显.
The phase-matching protocol is a practical and promising protocol that can surpass the linear key generation rate boundary.However,classical phase-matching quantum key distribution requires the channel attenuation between communicating parties to be symmetric.In practice,channels used are often asymmetric,owing to geographical reasons in a quantum key distribution network.To enhance the practicality of phasematching,this paper proposes an asymmetric phase-matching protocol based on the classical framework and establishes a relevant mathematical simulation model to study the influence of channel asymmetry on its performance.The simulation results show that channel asymmetry significantly affects the count rate,error rate,gain,and quantum bit error rate(QBER),ultimately,system performance.As the channel attenuation difference increases,the system performance decreases and the rate of decrease accelerates.Key generation becomes impossible when the channel attenuation difference exceeds 4 dB.Although the decoy-state scheme cannot change the system's tolerance to channel attenuation difference,when the channel attenuation difference is large,the increasing of the number of decoy states significantly can improve system performance,with a three-decoy-state phase-matching protocol outperforming a two-decoy-state protocol.Considering the limited data length,the system performance is improved as the data length increases,and the tolerance to channel attenuation differences gradually increases.When the data length exceeds 10^(12),this improvement does not continue any more.The system cannot break through the boundary of linear key generation rate when the channel attenuation difference is 2 dB and the data length is less than 10^(12).Comparing with symmetric channels,the system performance improvement is very significant under asymmetric channel conditions as the data length increases.
作者
周江平
周媛媛
周学军
Zhou Jiang-Ping;Zhou Yuan-Yuan;Zhou Xue-Jun(College of Electronic Engineering,Naval University of Engineering,Wuhan 430033,China)
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2023年第14期37-46,共10页
Acta Physica Sinica
关键词
量子密钥分发
相位匹配
非对称信道
信道衰减差
quantum key distribution
phase matching
asymmetric channel
channel attenuation difference
