Twin-field quantum key distribution (TF-QKD) is widely studied since it can surpass the key capacity of repeaterless QKD, whereas electromagnetic interference (EMI) is one of the main challenges in its practical applications. This study is based on the Faraday–Michelson TF-QKD. Analyze the effect of EMI on the rotation angle of the Faraday mirror causing an additional quantum bit error rate (QBER). Moreover, the quantum annealing algorithm (QA) based on quantum tunneling mechanism is applied to the optimization of practical TF-QKD. Mapping the secure key rate of TF-QKD into the evaluation function of QA and the transverse magnetic field is introduced to construct the kinetic energy term, which can realize the quantum tunneling effect. Meanwhile, the QA is improved in terms of chaotic optimization to obtain the dynamic initial value of the algorithm, the design of a perturbation method to skip the locally optimal solution, and the use of suitable temperature and magnetic field decay functions. Optimizing TF-QKD with QA, the standard deviation of QBER fluctuation caused by EMI is reduced to 0.206, the mean square error of the signal-state pulse intensity is only 3.38×10−4, and the optimization accuracy of the secure key rate can reach 99.8 %. Additionally, this optimization method shortens the runtime and reduces computational resource consumption, making it highly efficient for practical implementations.

中文翻译：

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基于量子退火算法的实用双场量子密钥分配参数优化


双场量子密钥分发（TF-QKD）因其可以超越无中继QKD的密钥容量而受到广泛研究，而电磁干扰（EMI）是其实际应用中的主要挑战之一。本研究基于法拉第-迈克尔逊 TF-QKD。分析 EMI 对法拉第镜旋转角度的影响，从而导致额外的量子误码率 (QBER)。此外，基于量子隧道机制的量子退火算法（QA）被应用于实际TF-QKD的优化。将TF-QKD的安全密钥率映射到QA的评价函数中，引入横向磁场构造动能项，实现量子隧道效应。同时，在混沌优化以获得算法的动态初始值、设计扰动方法以跳过局部最优解以及使用合适的温度和磁场衰减函数等方面对QA进行了改进。通过QA优化TF-QKD，EMI引起的QBER波动标准差降低至0.206，信号态脉冲强度均方误差仅为3.38×10−4，安全密钥速率的优化精度可提高达到99.8%。此外，这种优化方法缩短了运行时间并减少了计算资源消耗，使其在实际实现中非常高效。