Spins associated to solid-state colour centers are a promising platform for investigating quantum computation and quantum networks. Recent experiments have demonstrated multi-qubit quantum processors, optical interconnects, and basic quantum error correction protocols. One of the key open challenges towards larger-scale systems is to realize high-fidelity universal quantum gates. In this work, we design and demonstrate a complete high-fidelity gate set for the two-qubit system formed by the electron and nuclear spin of a nitrogen-vacancy center in diamond. We use gate set tomography (GST) to systematically optimise the gates and demonstrate single-qubit gate fidelities of up to 99.999(1)% and a two-qubit gate fidelity of 99.93(5)%. Our gates are designed to decouple unwanted interactions and can be extended to other electron-nuclear spin systems. The high fidelities demonstrated provide new opportunities towards larger-scale quantum processing with colour-center qubits.
@article{arxiv.2403.10633,
title = {Universal high-fidelity quantum gates for spin-qubits in diamond},
author = {H. P. Bartling and J. Yun and K. N. Schymik and M. van Riggelen and L. A. Enthoven and H. B. van Ommen and M. Babaie and F. Sebastiano and M. Markham and D. J. Twitchen and T. H. Taminiau},
journal= {arXiv preprint arXiv:2403.10633},
year = {2024}
}