发表机构
School of Electronics and Information Technology, Sun Yat-sen University（中山大学电子与信息工程学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
研究基于相位共轭孪生光束的确定性最小泄漏连续变量量子密钥分发，提出去除爱丽丝端宣告步骤的双模协议，分析其与宣告协议的关系及不同压缩下的密钥率，还研究了相关双模高斯攻击，表明该方法为对称最小泄漏 CV-QKD 提供新途径。
AI 中文摘要
最小泄漏连续变量量子密钥分发通过在状态制备阶段设计信号系综来抑制伊芙的 Holevo 信息。现有的对称最小泄漏协议通过宣告实现此目标：爱丽丝干涉两个压缩系综，测量一个输出模式，并将另一个发送给鲍勃。本文提出一种确定性双模协议，去除了爱丽丝端的宣告步骤。爱丽丝在平衡分束器上组合两个反向压缩的高斯系综，并传输两个输出模式，它们形成相位共轭孪生光束。我们表明该协议通过基于纠缠的共同源与宣告协议相关，但对应于不同的制备和测量分解。在大压缩极限下，两种协议每传输光学模式给出相同的密钥率。然而，对于有限压缩，相位共轭孪生光束协议需要少约 3 dB 的压缩来实现相同的密钥率。我们进一步分析了伊芙注入具有优化模式间相关性的辅助模式的相关双模高斯攻击。我们发现相关攻击比独立攻击稍有效，但在最小泄漏条件下优势仍然有限。这些结果表明相位共轭孪生光束为对称最小泄漏 CV-QKD 提供了一条确定性且具有实验吸引力的途径。
英文摘要
Minimum-leakage continuous-variable quantum key distribution suppresses Eve's Holevo information by engineering the signal ensemble during state preparation. The existing symmetric realization relies on Alice-side heralding. Here we propose an alternative two-mode symmetric realization that is deterministic without heralding. The minimum-leakage condition of the new protocol requires transmitting two phase-conjugated twin beams (PCTB). We show that the PCTB protocol is related to the heralding protocol through a common entanglement-based source but corresponds to a different prepare-and-measure decomposition. The two protocols attain the same secret key rate per transmitted optical mode in the very-large-squeezing limit. For finite squeezing, however, the PCTB protocol requires approximately 3 dB less squeezing to achieve the same performance. We further optimize mode-symmetric Gaussian two-mode entangling-cloner attacks and find that correlated ancillary modes provide only a limited advantage over independent attacks under the minimum-leakage condition. These results establish phase-conjugated twin beams as a deterministic and experimentally appealing route to symmetric minimum-leakage CV-QKD.
