论文标题
微波制度中的双向秘密量子通信
Two-way covert quantum communication in the microwave regime
论文作者
论文摘要
量子通信通过采用基于量子机械定律的加密技术来解决跨宏观距离交换信息的问题。在这里，我们通过将反向散射概念与微波处理中的秘密通信相结合，推进了一个新的范式，以进行安全量子通信。我们的协议允许仅使用离散相位调制的爱丽丝和有能访问低温微波技术的鲍勃。使用量子通道歧视和量子计量学的概念，我们找到了接收器性能的最终界限，证明量子相关性可以增强SNR高达$ 6 $ dB。这些界限排除了当源被强烈扩增时任何量子照明优势，并表明仅在低光子数字方面才有可能获得相关的增益。我们展示了如何将协议用于秘密通信，其中载体信号与环境中的热噪声无法区分。我们通过在电路平台中提供可行的实验建议来补充我们的信息理论结果。在以前未知的$ 1 $ - $ 10 $ GHz频率范围内，在一方严格限制的一方的可支配能力时，这项工作朝着实施安全的量子通信概念迈出了决定性的一步。
Quantum communication addresses the problem of exchanging information across macroscopic distances by employing encryption techniques based on quantum mechanical laws. Here, we advance a new paradigm for secure quantum communication by combining backscattering concepts with covert communication in the microwave regime. Our protocol allows communication between Alice, who uses only discrete phase modulations, and Bob, who has access to cryogenic microwave technology. Using notions of quantum channel discrimination and quantum metrology, we find the ultimate bounds for the receiver performance, proving that quantum correlations can enhance the SNR by up to $6$ dB. These bounds rule out any quantum illumination advantage when the source is strongly amplified, and show that a relevant gain is possible only in the low photon-number regime. We show how the protocol can be used for covert communication, where the carrier signal is indistinguishable from the thermal noise in the environment. We complement our information-theoretic results with a feasible experimental proposal in a circuit-QED platform. This work makes a decisive step toward implementing secure quantum communication concepts in the previously uncharted $1$-$10$ GHz frequency range, in the scenario when the disposable power of one party is severely constrained.
