Ground-state phase diagram and parity-flipping microwave transitions in a gate-tunable Josephson junction

We probed a gate-tunable InAs nanowire Josephson weak link by coupling it to a microwave resonator. Tracking the resonator frequency shift when the weak link is close to pinch-off, we observe that the ground state of the latter alternates between a singlet and a doublet when varying either the gate...

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Detalles Bibliográficos
Autores: Sahu, M.R., Matute-Cañadas, F.J., Benito, M., Krogstrup, P., Nygård, J., Goffman, M. F., Urbina, C., Yeyati, A. Levy, Pothier, H.
Tipo de recurso: artículo
Fecha de publicación:2024
País:España
Institución:Universidad Autónoma de Madrid
Repositorio:Biblos-e Archivo. Repositorio Institucional de la UAM
Idioma:inglés
OAI Identifier:oai:repositorio.uam.es:10486/716748
Acceso en línea:http://hdl.handle.net/10486/716748
https://dx.doi.org/10.1103/PhysRevB.109.134506
Access Level:acceso abierto
Palabra clave:Ground state
III-V semiconductors
indium arsenide
microwave devices
microwave spectroscopy
quantum optics
Física
Descripción
Sumario:We probed a gate-tunable InAs nanowire Josephson weak link by coupling it to a microwave resonator. Tracking the resonator frequency shift when the weak link is close to pinch-off, we observe that the ground state of the latter alternates between a singlet and a doublet when varying either the gate voltage or the superconducting phase difference across it. The corresponding microwave absorption spectra display lines that approach zero energy close to the singlet-doublet boundaries, suggesting parity-flipping transitions, which are in principle forbidden in microwave spectroscopy and expected to arise only in tunnel spectroscopy. We tentatively interpret them by means of an ancillary state isolated in the junction acting as a reservoir for individual electrons