We design a quantum repeater architecture using individual 167 Er ions doped into Y 2 SiO 5 crystal. This ion is a promising candidate for a repeater protocol because of its long hyperfine coherence time in addition to its ability to emit photons within the telecommunication wavelength range. To distribute entanglement over a long distance, we propose two different swapping gates between nearby ions using the exchange of virtual cavity photons and the electric dipole–dipole interaction. We analyze their expected performance, and discuss their strengths and weaknesses. Then, we show that a post-selection approach can be implemented to improve the gate fidelity of the virtual photon exchange scheme by monitoring cavity emission. Finally, we use our results for the swapping gates to estimate the end-to-end fidelity and distribution rate for the protocol.

中文翻译：

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与单个167 Er离子进行长距离量子通信的协议

我们使用掺入Y 2 SiO 5晶体中的167个单独的Er离子设计了一个量子中继器体系结构。该离子由于其超细的相干时间长，以及在电信波长范围内发射光子的能力，因此是转发器协议的有希望的候选者。为了在长距离上分布纠缠，我们使用虚拟腔光子的交换和电偶极-偶极相互作用建议了附近离子之间的两个不同的交换门。我们分析了它们的预期性能，并讨论了它们的优缺点。然后，我们表明可以通过监视腔体发射来实施后选择方法来提高虚拟光子交换方案的门保真度。最后，