Remote Quantum Networking with Single Rare-earth Ions: Bipartite Entanglement and Teleportation*

Long range quantum networks will enable secure communication and distributed quantum computing. In this talk we implement a two node network using single ¹⁷¹Yb ions in YVO₄ coupled to nanophotonic cavities. These are excellent optically-addressable qubits with high spin control fidelities, long memory times and stable optical transitions.

We apply a novel entanglement protocol to remote ¹⁷¹Yb ions that demonstrates two key milestones:

1. Optical lifetime-limited entanglement rates and fidelities, even in the presence of spectral diffusion;

2. Entanglement of optically distinguishable spin qubits without optical frequency shifting.

Counteracting both static and dynamic disorder in optical transition frequencies is achieved using the stochastic detection time of a heralding photon to tailor subsequent optical and spin quantum gates in real-time. We also apply a modified version of this protocol to probabilistically teleport quantum states between the two ions.

These results challenge conventional wisdom regarding limitations on entanglement protocols imposed by optical Ramsey coherence times. Furthermore, the narrow optical inhomogeneity of ¹⁷¹Yb:YVO₄ (200 MHz) enables entanglement distribution between any pair of ¹⁷¹Yb qubits with commercially available detector technology. These results showcase single rare-earth ions as a scalable platform for the future quantum internet.