量子密钥分发与设备无关量子密钥分发的优势蒸馏中的量子Chernoff散度
Quantum Chernoff divergence in advantage distillation for quantum key distribution and device-independent quantum key distribution
AI总结：
本文用量子Chernoff散度替代保真度，为重复码优势蒸馏协议建立了匹配的充分与必要安全条件，从而提升了设备无关量子密钥分发的噪声容忍阈值。
摘要：
设备无关量子密钥分发（DIQKD）旨在通过提供一种在适度安全假设下进行密钥蒸馏的方法，来缓解对手对量子设备缺陷的利用。优势蒸馏是纠错中的一种双向通信过程，已被证明能有效提高设备相关和设备无关QKD的噪声容忍度。此前，针对一种称为重复码协议的优势蒸馏协议，已经开发了针对独立同分布（IID）集体攻击的设备无关安全性证明，其依据涉及协议中某些态之间保真度的安全条件。然而，充分安全条件与必要安全条件之间存在差距，这阻碍了基于保真度计算紧致噪声容忍界限。我们通过提出一种替代证明结构来弥补这一差距，该结构用量子Chernoff散度取代保真度，量子Chernoff散度是一种在对称假设检验中出现的可区分性度量。在IID集体攻击模型下，我们针对重复码协议的安全性，推导出匹配的充分条件和必要条件（后者基于一个自然猜想），并以量子Chernoff散度表示，从而表明该散度是此协议中值得关注的相关量。此外，利用这一安全条件，我们在DIQKD的噪声容忍阈值方面获得了对先前结果的一些改进。我们的结果为量子信息理论中一个关于DIQKD在何种条件下可行的基本问题提供了洞见。
英文摘要：
Device-independent quantum key distribution (DIQKD) aims to mitigate adversarial exploitation of imperfections in quantum devices, by providing an approach for secret key distillation with modest security assumptions. Advantage distillation, a two-way communication procedure in error correction, has proven effective in raising noise tolerances in both device-dependent and device-independent QKD. Previously, device-independent security proofs against IID collective attacks were developed for an advantage distillation protocol known as the repetition-code protocol, based on security conditions involving the fidelity between some states in the protocol. However, there exists a gap between the sufficient and necessary security conditions, which hinders the calculation of tight noise-tolerance bounds based on the fidelity. We close this gap by presenting an alternative proof structure that replaces the fidelity with the quantum Chernoff divergence, a distinguishability measure that arises in symmetric hypothesis testing. Working in the IID collective attacks model, we derive matching sufficient and necessary conditions for the repetition-code protocol to be secure (up to a natural conjecture regarding the latter case) in terms of the quantum Chernoff divergence, hence indicating that this serves as the relevant quantity of interest for this protocol. Furthermore, using this security condition we obtain some improvements over previous results on the noise tolerance thresholds for DIQKD. Our results provide insight into a fundamental question in quantum information theory regarding the circumstances under which DIQKD is possible.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
