A quantum internet is the holy grail of quantum information processing, enabling the deployment of a broad range of quantum technologies and protocols on a global scale. However, numerous challenges must be addressed before the quantum internet can become a reality. Perhaps the most crucial of these is the realization of a quantum repeater, an essential component in the long-distance transmission of quantum information. As the analog of a classical repeater, extender, or booster, the quantum repeater works to overcome loss and noise in the quantum channels constituting a quantum network. Here the conceptual frameworks and architectures for quantum repeaters, as well as the experimental progress toward their realization, are reviewed. Various near-term proposals to overcome the limits to the communication rates set by point-to-point quantum communication are also discussed. Finally, the manner in which quantum repeaters fit within the broader challenge of designing and implementing a quantum internet is overviewed.

中文翻译：

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量子中继器：从量子网络到量子互联网

量子互联网是量子信息处理的圣杯，能够在全球范围内部署广泛的量子技术和协议。然而，在量子互联网成为现实之前，必须解决众多挑战。也许其中最关键的是量子中继器的实现，它是量子信息长距离传输的重要组成部分。作为经典中继器、扩展器或增强器的模拟，量子中继器的作用是克服构成量子网络的量子通道中的损耗和噪声。这里回顾了量子中继器的概念框架和架构，以及实现它们的实验进展。还讨论了克服点对点量子通信所设定的通信速率限制的各种近期建议。最后，概述了量子中继器如何适应设计和实施量子互联网的更广泛挑战。