Coherent control of a single nuclear spin near an Er³⁺ ion

Single erbium ions in solid-state hosts are excellent candidates for quantum network applications due to their emission in the telecom band and compatibility with silicon photonics, while nuclear spins provide coherent resources for quantum information processing. In this work, we observe coherent coupling of an Er electronic spin (S=1/2) in a Y₂SiO₅ host crystal, and a nearby nuclear spin (I=1/2), with a measured gyromagnetic ratio equivalent to a proton. We utilize this interaction to construct a SWAP operation, measure the coherence properties of the nuclear spin, identify its location with respect to the Er ion and probe its environment. In particular, by performing spectroscopy on the nuclear spin, we find that it is coupled to a system consistent with two spin-1/2 nuclear spins. These results provide a pathway towards interacting spin ensembles, combining multiple long-lived quantum registers to a telecom-compatible quantum memory for future quantum repeater-based quantum network applications.

Support for this work was provided by AFOSR, DOE and DARPA DRINQS.