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arXiv · 2208.10094

Direct manipulation of a superconducting spin qubit strongly coupled to a transmon qubit

Marta Pita-Vidal·Arno Bargerbos·Rok Žitko·Lukas J. Splitthoff·Lukas Grünhaupt·Jaap J. Wesdorp·Yu Liu·Leo P. Kouwenhoven·Ramón Aguado·Bernard van Heck·Angela Kou·Christian Kraglund Andersen
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Abstract

Spin qubits in semiconductors are currently one of the most promising architectures for quantum computing. However, they face challenges in realizing multi-qubit interactions over extended distances. Superconducting spin qubits provide a promising alternative by encoding a qubit in the spin degree of freedom of an Andreev level. Such an Andreev spin qubit could leverage the advantages of circuit quantum electrodynamic, enabled by an intrinsic spin-supercurrent coupling. The first realization of an Andreev spin qubit encoded the qubit in the excited states of a semiconducting weak-link, leading to frequent decay out of the computational subspace. Additionally, rapid qubit manipulation was hindered by the need for indirect Raman transitions. Here, we exploit a different qubit subspace, using the spin-split doublet ground state of an electrostatically-defined quantum dot Josephson junction with large charging energy. Additionally, we use a magnetic field to enable direct spin manipulation over a frequency range of 10 GHz. Using an all-electric microwave drive we achieve Rabi frequencies exceeding 200 MHz. We furthermore embed the Andreev spin qubit in a superconducting transmon qubit, demonstrating strong coherent qubit-qubit coupling. These results are a crucial step towards a hybrid architecture that combines the beneficial aspects of both superconducting and semiconductor qubits.

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Marta Pita-Vidal, Arno Bargerbos, Rok Žitko, Lukas J. Splitthoff, Lukas Grünhaupt, Jaap J. Wesdorp, Yu Liu, Leo P. Kouwenhoven, Ramón Aguado, Bernard van Heck, Angela Kou, Christian Kraglund Andersen. 2022-08-22. Direct manipulation of a superconducting spin qubit strongly coupled to a transmon qubit. https://doi.org/10.1038/s41567-023-02071-x

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