We study the implementation of quantum-key-distribution (QKD) systems over quantum-repeater infrastructures. We particularly consider quantum repeaters with encoding and compare them with probabilistic quantum repeaters. To that end, we propose two decoder structures for encoded repeaters that not only aid system performance but also make the implementation aspects easier by removing two-qubit gates from the QKD decoder. By developing several scalable numerical and analytical techniques, we then identify the resilience of the setup to various sources of error in gates, measurement modules, and initialization of the setup. We apply our techniques to three- and five-qubit repetition codes and obtain the normalized secret key generation rate per memory per second for encoded and probabilistic quantum repeaters. We quantify the regimes of operation, where one class of repeater outperforms the other, and find that there are feasible regimes of operation where encoded repeaters—based on simple three-qubit repetition codes—could offer practical advantages.

中文翻译：

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用于编码器的量子中继器上的量子密钥分配的简单高效解码器

我们研究了基于量子中继器基础结构的量子密钥分发（QKD）系统的实现。我们特别考虑编码的量子中继器，并将其与概率量子中继器进行比较。为此，我们为编码的中继器提出了两种解码器结构，它们不仅可以提高系统性能，而且还可以通过从QKD解码器中删除两个量子比特的门来简化实现方面。通过开发几种可扩展的数值和分析技术，我们然后确定设置对门，测量模块和设置初始化中各种错误源的弹性。我们将我们的技术应用于三和五比特重复码，并获得了编码和概率量子重复器每秒每个存储器的归一化秘密密钥生成率。我们量化运作方式，