Quantum teleportation and entanglement distribution over 100-kilometre free-space channels
Quantum teleportation and entanglement distribution over 100-kilometre free-space channels
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DOI：
10.1038/nature11332
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发表时间：
2012-05
期刊：
影响因子：
64.8
通讯作者：
Juan Yin;Ji-Gang Ren;He Lu;Yuan Cao;Hai-Lin Yong;Yu-Ping Wu;Chang Liu;Shengkai Liao;Fei Zhou
中科院分区：
文献类型：
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作者：
Juan Yin;Ji-Gang Ren;He Lu;Yuan Cao;Hai-Lin Yong;Yu-Ping Wu;Chang Liu;Shengkai Liao;Fei Zhou
在任意距离上传输未知量子态对于大规模量子通信和分布式量子网络是必不可少的。这可以借助远距离量子隐形传态和纠缠分布来实现。后者对于量子力学定律的基本测试也很重要。虽然使用光纤链路可以实现中等距离上的量子隐形传态和纠缠分布，但光纤中巨大的光子损耗和退相干要求在较大距离上使用量子中继器。然而，量子中继器的实际实现在实验上仍然具有挑战性。首先用于量子密钥分发的自由空间信道提供了一种更有前途的方法，因为光子损失和退相干在大气中几乎可以忽略不计。此外，利用卫星可以在全球范围内实现超远距离量子通信和量子基础测试。先前的实验已经实现了600米（参考文献）和13公里（参考文献）距离上纠缠光子对的自由空间分布，以及144公里单链自由空间通道上触发的单光子传输。最近，根据一个改进的方案，用一对纠缠光子演示了超过16公里的自由空间量子隐形传态。在这里，我们报告了在97公里的单链路自由空间通道上具有多光子纠缠的独立量子比特的量子隐形传态。在六个不同的州，平均保真度达到80.4±0.9%。此外，我们证明了在双链路信道上的纠缠分布，其中纠缠光子相隔101.8公里。clauser - horn - shimony - holt不等式的违反没有局部性漏洞。除了具有根本性的意义外，我们的研究结果还代表了迈向全球量子网络的重要一步。此外，我们在实验中开发的高频高精度获取、指向和跟踪技术可以直接用于未来的卫星量子通信和量子基础的大规模测试。
Transferring an unknown quantum state over arbitrary distances is essential for large-scale quantum communication and distributed quantum networks. It can be achieved with the help of long-distance quantum teleportation,and entanglement distribution. The latter is also important for fundamental tests of the laws of quantum mechanics,. Although quantum teleportation,and entanglement distribution,,over moderate distances have been realized using optical fibre links, the huge photon loss and decoherence in fibres necessitate the use of quantum repeaters for larger distances. However, the practical realization of quantum repeaters remains experimentally challenging. Free-space channels, first used for quantum key distribution,, offer a more promising approach because photon loss and decoherence are almost negligible in the atmosphere. Furthermore, by using satellites, ultra-long-distance quantum communication and tests of quantum foundations could be achieved on a global scale. Previous experiments have achieved free-space distribution of entangled photon pairs over distances of 600 metres (ref. ) and 13 kilometres (ref. ), and transfer of triggered single photons over a 144-kilometre one-link free-space channel. Most recently, following a modified scheme, free-space quantum teleportation over 16 kilometres was demonstrated with a single pair of entangled photons. Here we report quantum teleportation of independent qubits over a 97-kilometre one-link free-space channel with multi-photon entanglement. An average fidelity of 80.4 ± 0.9 per cent is achieved for six distinct states. Furthermore, we demonstrate entanglement distribution over a two-link channel, in which the entangled photons are separated by 101.8 kilometres. Violation of the Clauser–Horne–Shimony–Holt inequality is observed without the locality loophole. Besides being of fundamental interest, our results represent an important step towards a global quantum network. Moreover, the high-frequency and high-accuracy acquiring, pointing and tracking technique developed in our experiment can be directly used for future satellite-based quantum communication and large-scale tests of quantum foundations.