Quantum repeaters have been proposed as a way of extending the reach of quantum communication. First-generation approaches use entanglement swapping to connect entangled links along a long-distance channel. Recently, there have been proposals for first-generation quantum repeaters for continuous variables. In this paper, we present an improved continuous-variable (CV) repeater scheme using optimal Gaussian entanglement swapping. Our scheme uses the noiseless linear amplifier for entanglement distillation. We show that with the simplest configuration of the noiseless linear amplifier and under the assumption of good quantum memories and perfect sources and detectors, our scheme beats the direct transmission upper limit for shorter distances and can offer advantages over previous CV repeater schemes.

中文翻译：

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用于连续可变纠缠分布的量子中继器

已经提出了量子中继器，作为扩展量子通信范围的一种方式。第一代方法使用纠缠交换来沿长距离通道连接纠缠链路。近来，已经提出了用于连续变量的第一代量子中继器的建议。在本文中，我们提出了一种使用最佳高斯纠缠交换的改进的连续变量（CV）中继器方案。我们的方案使用无噪声线性放大器进行纠缠蒸馏。我们表明，采用无噪声线性放大器的最简单配置，并在良好的量子存储以及完善的信号源和检测器的假设下，我们的方案在较短的距离上超过了直接传输的上限，并且可以提供优于以前的CV中继器方案的优势。