Microwave spectroscopy of interacting Andreev spins

Fuente: arXiv
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Autori principali: Wesdorp, J. J., Matute-Caňadas, F. J., Vaartjes, A., Grünhaupt, L., Laeven, T., Roelofs, S., Splitthoff, L. J., Pita-Vidal, M., Bargerbos, A., van Woerkom, D. J., Krogstrup, P., Kouwenhoven, L. P., Andersen, C. K., Yeyati, A. Levy, van Heck, B., de Lange, G.
Natura: Preprint
Pubblicazione: 2022
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author Wesdorp, J. J.
Matute-Caňadas, F. J.
Vaartjes, A.
Grünhaupt, L.
Laeven, T.
Roelofs, S.
Splitthoff, L. J.
Pita-Vidal, M.
Bargerbos, A.
van Woerkom, D. J.
Krogstrup, P.
Kouwenhoven, L. P.
Andersen, C. K.
Yeyati, A. Levy
van Heck, B.
de Lange, G.
author_facet Wesdorp, J. J.
Matute-Caňadas, F. J.
Vaartjes, A.
Grünhaupt, L.
Laeven, T.
Roelofs, S.
Splitthoff, L. J.
Pita-Vidal, M.
Bargerbos, A.
van Woerkom, D. J.
Krogstrup, P.
Kouwenhoven, L. P.
Andersen, C. K.
Yeyati, A. Levy
van Heck, B.
de Lange, G.
contents Andreev bound states are fermionic states localized in weak links between superconductors which can be occupied with spinful quasiparticles. Microwave experiments using superconducting circuits with InAs/Al nanowire Josephson junctions have recently enabled probing and coherent manipulation of Andreev states but have remained limited to zero or small fields. Here we use a flux-tunable superconducting circuit in external magnetic fields up to 1T to perform spectroscopy of spin-polarized Andreev states up to ~250 mT, beyond which the spectrum becomes gapless. We identify singlet and triplet states of two quasiparticles occupying different Andreev states through their dispersion in magnetic field. These states are split by exchange interaction and couple via spin-orbit coupling, analogously to two-electron states in quantum dots. We also show that the magnetic field allows to drive a direct spin-flip transition of a single quasiparticle trapped in the junction. Finally, we measure a gate- and field-dependent anomalous phase shift of the Andreev spectrum, of magnitude up to approximately $0.7π$. Our observations demonstrate new ways to manipulate Andreev states in a magnetic field and reveal spin-polarized triplet states that carry supercurrent.
format Preprint
id arxiv_https___arxiv_org_abs_2208_11198
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Microwave spectroscopy of interacting Andreev spins
Wesdorp, J. J.
Matute-Caňadas, F. J.
Vaartjes, A.
Grünhaupt, L.
Laeven, T.
Roelofs, S.
Splitthoff, L. J.
Pita-Vidal, M.
Bargerbos, A.
van Woerkom, D. J.
Krogstrup, P.
Kouwenhoven, L. P.
Andersen, C. K.
Yeyati, A. Levy
van Heck, B.
de Lange, G.
Mesoscale and Nanoscale Physics
Superconductivity
Quantum Physics
Andreev bound states are fermionic states localized in weak links between superconductors which can be occupied with spinful quasiparticles. Microwave experiments using superconducting circuits with InAs/Al nanowire Josephson junctions have recently enabled probing and coherent manipulation of Andreev states but have remained limited to zero or small fields. Here we use a flux-tunable superconducting circuit in external magnetic fields up to 1T to perform spectroscopy of spin-polarized Andreev states up to ~250 mT, beyond which the spectrum becomes gapless. We identify singlet and triplet states of two quasiparticles occupying different Andreev states through their dispersion in magnetic field. These states are split by exchange interaction and couple via spin-orbit coupling, analogously to two-electron states in quantum dots. We also show that the magnetic field allows to drive a direct spin-flip transition of a single quasiparticle trapped in the junction. Finally, we measure a gate- and field-dependent anomalous phase shift of the Andreev spectrum, of magnitude up to approximately $0.7π$. Our observations demonstrate new ways to manipulate Andreev states in a magnetic field and reveal spin-polarized triplet states that carry supercurrent.
title Microwave spectroscopy of interacting Andreev spins
topic Mesoscale and Nanoscale Physics
Superconductivity
Quantum Physics
url https://arxiv.org/abs/2208.11198