基于后选择的连续变量量子密钥分发协议

连续变量量子密钥分发（CVQKD）是利用连续变化的物理量承载密钥的量子密钥分发协议，与电力系统普遍采用的离散变量量子密钥分发协议相比，其具有设备简单、探测效率高、兼容性好等优点，成为量子密钥分发的研究热点。然而，量子态在量子信道中的传输衰减严重限制CVQKD传输距离。提出了一种基于后选择方法的CVQKD协议，且不需要额外的单光子源。研究结果表明，该后选择方法中测量值越大的物理量被保留下的概率越高。该方法可以简化并降低连续量子密钥分发协议实现的成本，为探索出电力网络的量子保密通信方案提供研究思路。

Continuous-Variable Quantum Key Distribution Protocol Based on Post-Selection

Compared with discrete-variable quantum key distribution (DVQKD) protocol that has been widely used in power system, the continuous-variable quantum key distribution (CVQKD), which uses continuous variables to perform QKD protocol, has such advantages as simple equipment, high detection efficiency and good compatibility, and has attracted wide attentions. However, the attenuation in the quantum state transmission heavily reduces the propagation distance of CVQKD. In the paper, we present a CVQKD protocol based on post-selection method, which need not any extra single photon source. The results show that the higher probability values are all reserved and amplified by the post selection window function. The proposed method can simplify the implementation of CVQKD and reduce its cost, and can also provide ideas for studying the quantum secure communication schemes in power network.