Coherent Microwave, Optical, and Mechanical Quantum Control of Spin Qubits in Diamond

• Published in: Advanced quantum technologies (Online) Vol. 8; no. 2
• Main Authors: Orphal‐Kobin, Laura, Torun, Cem Güney, Bopp, Julian M., Pieplow, Gregor, Schröder, Tim
• Format: Journal Article
• Language: English
• Published: 01.02.2025
• Subjects: color centers in diamond; optically active solid‐state spin defects; quantum control; quantum information processing; quantum optics; quantum technology; review
• ISSN: 2511-9044; 2511-9044
• DOI: 10.1002/qute.202300432

Diamond has emerged as a highly promising platform for quantum network applications. Color centers in diamond fulfill the fundamental requirements for quantum nodes: they constitute optically accessible quantum systems with long‐lived spin qubits. Furthermore, they provide access to a quantum register of electronic and nuclear spin qubits and they mediate entanglement between spins and photons. All these operations require coherent control of the color center's spin state. This review provides a comprehensive overview of the state‐of‐the‐art, challenges, and prospects of such schemes, including high‐fidelity initialization, coherent manipulation, and readout of spin states. Established microwave and optical control techniques are reviewed, and moreover, emerging methods such as cavity‐mediated spin–photon interactions and mechanical control based on spin–phonon interactions are summarized. For different types of color centers, namely, nitrogen–vacancy and group‐IV color centers, distinct challenges persist that are subject of ongoing research. Beyond fundamental coherent spin qubit control techniques, advanced demonstrations in quantum network applications are outlined, for example, the integration of individual color centers for accessing (nuclear) multiqubit registers. Finally, the role of diamond spin qubits in the realization of future quantum information applications is described. Color centers in diamond are a promising platform for quantum network applications. They meet key requirements for quantum nodes, constituting optically active long‐lived spin qubits. The review explores coherent quantum control operations based on microwave and optical methods, alongside emerging techniques like cavity‐mediated spin–photon interaction and mechanical control. The role of diamond spin qubits in future quantum information applications becomes apparent.