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arXiv 2005.10146quant-ph
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空间量子中继器

Quantum repeaters in space

Carlo Liorni, Hermann Kampermann, Dagmar Bruss

摘要:

长距离纠缠是一种非常宝贵的资源,但由于光在光纤中的指数损耗,它的分布非常困难。一种可能的解决方案是使用基于纠缠交换或量子纠错的量子中继器。或者,可以利用卫星自由空间光链路,实现更好的损耗距离缩放。我们建议将这两种成分,量子中继器和基于卫星的链路,结合成一个方案,允许实现纠缠分布在全球范围内的少量中间不可信节点。放置在卫星上的纠缠源将以光子编码的量子态发送到轨道量子中继站,在那里进行纠缠交换。这个中继器链的性能进行评估的BB-84加密协议的密钥速率。我们与其他中继器链架构进行比较,并表明我们的方案是优越的,在几乎所有的情况下,实现更高的密钥速率,可靠性和灵活性。最后,我们分析了在中期实施的可行性,并讨论了示范性轨道配置。基于卫星的链路与地面中继器网络的集成可以被设想为未来量子互联网的骨干。

英文摘要:

Long-distance entanglement is a very precious resource, but its distribution is very difficult due to the exponential losses of light in optical fibres. A possible solution consists in the use of quantum repeaters, based on entanglement swapping or quantum error correction. Alternatively, satellite-based free-space optical links can be exploited, achieving better loss-distance scaling. We propose to combine these two ingredients, quantum repeaters and satellite-based links, into a scheme that allows to achieve entanglement distribution over global distances with a small number of intermediate untrusted nodes. The entanglement sources, placed on satellites, send quantum states encoded in photons towards orbiting quantum repeater stations, where entanglement swapping is performed. The performance of this repeater chain is assessed in terms of the secret key rate achievable by the BB-84 cryptographic protocol. We perform a comparison with other repeater chain architectures and show that our scheme is superior in almost every situation, achieving higher key rates, reliability and flexibility. Finally, we analyse the feasibility of the implementation in the mid-term future and discuss exemplary orbital configurations. The integration of satellite-based links with ground repeater networks can be envisaged to represent the backbone of the future Quantum Internet.

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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