基于旋转不变态的测量设备无关量子密钥分配协议研究

本文提出了一种基于旋转不变态的偏振无关测量设备量子密钥分配协议,既适用于偏振编码测量设备无关量子密钥分配系统,也应用于相位编码测量设备无关量子密钥分配系统的相干过程.通过在线偏振基进入信道传输前嵌入2块q玻片,使得在传输过程中将线偏振基转化为旋转不变的圆偏振基,而第三方对接收到的脉冲进行Bell态测量前,利用q玻片的算符可逆性,将圆偏振基还原为线偏振基进行测量,可以有效消除信道传输中偏振旋转导致的误码.本文分析了偏振无关的三诱骗态测量设备无关量子密钥分配系统的误码率,研究了密钥生成率与安全传输距离的关系,仿真结果表明,对于偏振编码测量设备无关量子密钥分配系统,该协议可以有效提高系统的最大安全通信距离,为实用的量子密钥分配实验提供了重要的理论参数.

Measurement of device-independent quantum key distribution for the rotation invariant photonic state

The original measurement of device-independent(MDI)quantum key distribution(QKD) is reviewed, and a modified protocol using rotation-invariant photonic state is proposed. Initial encoding and final decoding of information in our MDI-QKD implementation protocol can be conveniently performed in the polarization space, while the transmission is done in the rotation-invariant hybrid space. Our analysis indicates that both the secure key rate and transmission distance can be improved by our modified protocol owing to its lower error rate. Furthermore, our hybrid polarization-OAM qubits approach only needs to insert four q-plates in a practical experiment, and our simulation results show that the modified protocol is practical.
Keywords： rotation invariant photonic state polarization independent measurement device-independent quantum key distribution