Individually addressed Er3+ ions in solid-state hosts are promising resources for quantum repeaters, because of their direct emission in the telecom band and compatibility with silicon photonic devices. While the Er3+ electron spin provides a spin-photon interface, ancilla nuclear spins could enable multi-qubit registers with longer storage times. In this work, we demonstrate coherent coupling between the electron spin of a single Er3+ ion and a single I=1/2 nuclear spin in the solid-state host crystal, which is a fortuitously located proton (1H). We control the nuclear spin using dynamical decoupling sequences applied to the electron spin, implementing one- and two-qubit gate operations. Crucially, the nuclear spin coherence time exceeds the electron coherence time by several orders of magnitude, because of its smaller magnetic moment. These results provide a path towards combining long-lived nuclear spin quantum registers with telecom-wavelength emitters for long-distance quantum repeaters.
@article{arxiv.2209.05631,
title = {Coherent control of a nuclear spin via interactions with a rare-earth ion in the solid-state},
author = {Mehmet T. Uysal and Mouktik Raha and Songtao Chen and Christopher M. Phenicie and Salim Ourari and Mengen Wang and Chris G. Van de Walle and Viatcheslav V. Dobrovitski and Jeff D. Thompson},
journal= {arXiv preprint arXiv:2209.05631},
year = {2023}
}