High-fidelity control of a $^{13}$C nuclear spin coupled to a tin-vacancy center in diamond
Jeremias Resch, Ioannis Karapatzakis, Mohamed Elshorbagy, Marcel Schrodin, Philipp Fuchs, Philipp Graßhoff, Luis Kussi, Christoph Sürgers, Cyril Popov, Christoph Becher, Wolfgang Wernsdorfer, David Hunger
Published: 2025/9/3
Abstract
Nuclear spins near group-IV defects in diamond are promising candidates for quantum memories in quantum network applications. Here, we demonstrate high-fidelity control of a single $^{13}$C nuclear spin coupled to a tin-vacancy (SnV) center in diamond. We perform a combination of optical and microwave pumping to achieve initialization into a combined electro-nuclear spin state with a fidelity of $99.74(3)\,\%$. Harnessing a superconducting waveguide for radio-frequency driving, we demonstrate precise nuclear spin control: Ramsey measurements reveal a coherence time of $T_2^* = 1.5(1)\,$milliseconds, and we use dynamical decoupling to extend it to $1.35(3)\,$seconds. We perform randomized benchmarking, yielding a single-qubit gate fidelity of $99.92(1)\,\%$. This demonstrates a coherent spin-photon system with promising properties for quantum network nodes.