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arXiv 2202.10263quant-phcs.CRcs.ITmath.IT
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量子边信息保密放大的强逆问题

Strong Converse for Privacy Amplification against Quantum Side Information

Yu-Chen Shen, Li Gao, Hao-Chung Cheng

摘要:

以迹距离为安全判据,建立了针对量子边信息的隐私放大的一次强逆界。这个强逆界意味着,在独立和相同的情况下,迹距离指数收敛到一个在每个有限块长度时,提取的随机性的速率超过量子条件熵。所建立的单次界可用于限制经典量子窃听信道编码和量子信道上的保密通信的信息泄漏。也就是说,当散列中使用的随机率超过量子互信息时,Alice和Escherdropper的联合状态与其解耦状态之间的迹距离消失。另一方面,当速率低于量子互信息时,迹距离收敛于1,导致指数强逆。我们的结果还导致了熵累积的指数强逆,这补充了Dupuis [arXiv:2105.05342]最近的结果。最后,我们的结果及其应用适用于中等偏差区。也就是说,我们描述的渐近行为的轨迹距离时,相关的速率接近基本阈值的速度慢于$O(1/\sqrt{n})$。

英文摘要:

We establish a one-shot strong converse bound for privacy amplification against quantum side information using trace distance as a security criterion. This strong converse bound implies that in the independent and identical scenario, the trace distance exponentially converges to one in every finite blocklength when the rate of the extracted randomness exceeds the quantum conditional entropy. The established one-shot bound has an application to bounding the information leakage of classical-quantum wiretap channel coding and private communication over quantum channels. That is, the trace distance between Alice and Eavesdropper's joint state and its decoupled state vanishes as the rate of randomness used in hashing exceeds the quantum mutual information. On the other hand, the trace distance converges to one when the rate is below the quantum mutual information, resulting in an exponential strong converse. Our result also leads to an exponential strong converse for entropy accumulation, which complements a recent result by Dupuis [arXiv:2105.05342]. Lastly, our result and its applications apply to the moderate deviation regime. Namely, we characterize the asymptotic behaviors of the trace distances when the associated rates approach the fundamental thresholds with speeds slower than $O(1/\sqrt{n})$.

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。

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