Quantum key distribution (QKD) has reached a global scale by utilizing the powerful scheme in free space scenes with a more flexible transmission. Unfortunately, the practical applicability of free-space QKD is usually curtailed by the fact that the atmospheric turbulence unavoidably destructs the quality of the quantum signal, which limits its maximum transmission distance. Here we propose an attenuation scheme for the Gaussian modulated coherent state QKD, in which a quantum catalysis operation acts as a noiseless attenuation process to regulate the potentially deteriorated quantum signal, enabling the improvement of maximal transmission distance. Compared with the original protocol, the QC-assisted attenuation presents a promotion of maximum transmission distance. In particular, we find that the zero-photon catalysis-based protocol performs better than the QC-based one. Numerical analysis shows that the QC-assisted attenuation can reduce the amount of information obtained by ...

中文翻译：

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用于改善自由空间连续变量量子密钥分配的量子催化辅助衰减

通过在自由空间场景中使用功能强大的方案以及更灵活的传输，量子密钥分发（QKD）已达到全球范围。不幸的是，通常由于大气湍流不可避免地破坏了量子信号的质量，从而限制了其最大传输距离，从而限制了自由空间QKD的实用性。在这里，我们提出了一种针对高斯调制相干态QKD的衰减方案，其中量子催化操作可作为无噪声衰减过程来调节潜在恶化的量子信号，从而可以改善最大传输距离。与原始协议相比，QC辅助衰减有助于最大传输距离的提升。尤其是，我们发现基于零光子催化的协议比基于QC的协议性能更好。数值分析表明，QC辅助衰减可以减少通过...获得的信息量。