Universal high-fidelity quantum gates for spin-qubits in diamond

• DOI: 10.48550/arxiv.2403.10633
• Publication Date: 2024-01-01
• Authors: Bartling, H. P.; Yun, J.; Schymik, K. N.; van Riggelen, M.; Enthoven, L. A.; van Ommen, H. B.; Babaie, M.; Sebastiano, F.; Markham, M.; Twitchen, D. J.; Taminiau, T. H.
• Keywords: Quantum Physics; Condensed Matter - Mesoscale and Nanoscale Physics; Mesoscale and Nanoscale Physics (cond-mat.mes-hall); FOS: Physical sciences; Quantum Physics (quant-ph)

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.