Spectroscopy of Spin-Split Andreev Levels in a Quantum Dot with Superconducting Leads

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

Research output: Contribution to journalArticlepeer-review


We use a hybrid superconductor-semiconductor transmon device to perform spectroscopy of a quantum dot Josephson junction tuned to be in a spin-1/2 ground state with an unpaired quasiparticle. Because of spin-orbit coupling, we resolve two flux-sensitive branches in the transmon spectrum, depending on the spin of the quasiparticle. A finite magnetic field shifts the two branches in energy, favoring one spin state and resulting in the anomalous Josephson effect. We demonstrate the excitation of the direct spin-flip transition using all-electrical control. Manipulation and control of the spin-flip transition enable the future implementation of charging energy protected Andreev spin qubits.

Original languageEnglish (US)
Article number097001
JournalPhysical review letters
Issue number9
StatePublished - Sep 1 2023
Externally publishedYes

ASJC Scopus subject areas

  • General Physics and Astronomy


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