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arXiv 2108.08418quant-phcs.CRcs.ITmath.IT
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面向全球量子网络的优化多线程CV-QKD信息协调

Optimised Multithreaded CV-QKD Reconciliation for Global Quantum Networks

Xiaoyu Ai, Robert Malaney

AI总结:

针对CV-QKD信息协调耗时长、难以适配LEO卫星短过境时间的问题,研究人员通过分析验证大码长LDPC解码的分层协调协议,得出最优并行码块长度,显著提升密钥率,支持星地量子安全通信,为优化全球量子网络提供支撑。

摘要:

设计实用的连续变量(Continuous Variable, CV)量子密钥分发(Quantum Key Distribution, QKD)系统,需要估算量子信道特性,并基于大量分布式量子信号提取安全密钥比特,在短时间内满足这一要求难度很大。在标准处理器上,协调所需数量的量子信号可能需要数小时。而在低地球轨道(Low Earth Orbit, LEO)卫星CV-QKD场景下,卫星过境时间被限制在数分钟以内,这一问题会进一步加剧。该问题的一种潜在解决方案是对经典协调过程进行大规模并行化,即将大码块拆分为多个更短的码块分别解码。然而,这一过程对重要的最终安全密钥率的损耗难以确定,且迄今为止尚未得到正式分析。理想情况下,这类分析应能得出使最终密钥率最大化的最优缩减码块长度。在本研究中,我们通过对采用大码长低密度奇偶校验解码器的CV-QKD分层协调协议进行详细分析与实验验证,填补了这一重要的知识空白。我们的新方案相较于未优化的协调方法,能显著提升最终密钥率。此外,即便使用现成处理器,该方案也能在卫星过境时间内实现地面站与LEO卫星之间的量子安全消息传输。我们的工作为通过基础物理学保障安全的优化全球量子网络指明了方向。

英文摘要:

Designing a practical Continuous Variable (CV) Quantum Key Distribution (QKD) system requires an estimation of the quantum channel characteristics and the extraction of secure key bits based on a large number of distributed quantum signals. Meeting this requirement in short timescales is difficult. On standard processors, it can take several hours to reconcile the required number of quantum signals. This problem is exacerbated in the context of Low Earth Orbit (LEO) satellite CV-QKD, in which the satellite flyover time is constrained to be less than a few minutes. A potential solution to this problem is massive parallelisation of the classical reconciliation process in which a large-code block is subdivided into many shorter blocks for individual decoding. However, the penalty of this procedure on the important final secured key rate is non-trivial to determine and hitherto has not been formally analysed. Ideally, a determination of the optimal reduced block size, maximising the final key rate, would be forthcoming in such an analysis. In this work, we fill this important knowledge gap via detailed analyses and experimental verification of a CV-QKD sliced reconciliation protocol that uses large block-length low-density parity-check decoders. Our new solution results in a significant increase in the final key rate relative to non-optimised reconciliation. In addition, it allows for the acquisition of quantum secured messages between terrestrial stations and LEO satellites within a flyover timescale even using off-the-shelf processors. Our work points the way to optimised global quantum networks secured via fundamental physics.

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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