标题： 基于量子码分多址的连续变量量子密钥分发 显示英文标题

标题： Quantum code division multiple access based continuous-variable quantum key distribution

摘要： 在本文中，我们提出了一种基于量子码分多址（q-CDMA）的连续变量量子密钥分发（CV-QKD）系统。 在所提出的系统中，两个发送者（$\text{Alice}_{1,2}$）的量子态通过混沌相位调制器进行混沌编码，然后通过量子信道传输。 在接收端，通过混沌同步解码量子态，以分离不同发送者发送并由两个接收者（$\text{Bob}_{1,2}$）分别接收的量子态。 我们表征了两个发送者和接收者之间的正交分量的输入输出关系，然后分析了基于q-CDMA的CV-QKD系统的秘密密钥速率（SKR）。 我们的数值结果表明，与没有q-CDMA方法的单用户情况相比，q-CDMA方法可以显著提高两个用户的SKR。 显示英文摘要

摘要： In this paper, we propose a quantum code division multiple access (q-CDMA) based continuous-variable quantum key distribution (CV-QKD) system. In the proposed system, the quantum states of two senders ($\text{Alice}_{1,2}$) are chaotically encoded through chaotic phase shifters and then transmitted over a quantum channel. At the receiver, the quantum states are decoded via chaos synchronization to separate the quantum states sent by the different senders and received by the two receivers ($\text{Bob}_{1,2}$) separately. We characterize the input-output relation of the quadrature between the two senders and receivers and then analyze the secret key rate (SKR) of the q-CDMA-based CV-QKD system. Our numerical results reveal that the q-CDMA approach can significantly enhance the SKR for both users when compared to the single-user case without the q-CDMA approach.