Ground state phase diagram and "parity flipping'' microwave transitions in a gate-tunable Josephson Junction

Abstract

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.

References in corpus (11)

• Epitaxy of Semiconductor-Superconductor nanowires
• Josephson current through a single Anderson impurity coupled to BCS leads
• Direct manipulation of a superconducting spin qubit strongly coupled to a transmon qubit
• Kondo effect in asymmetric Josephson couplings through a quantum dot
• Signatures of interactions in the Andreev spectrum of nanowire Josephson junctions
• Spectroscopy of spin-split Andreev levels in a quantum dot with superconducting leads
• Study of 0-$\pi$ phase transition in hybrid superconductor-InSb nanowire quantum dot devices
• From adiabatic to dispersive readout of quantum circuits
• Microwave spectroscopy of interacting Andreev spins
• Dynamical parity selection in superconducting weak links
• Inductive microwave response of Yu-Shiba-Rusinov states

Cited by in corpus (9)

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• Andreev spin relaxation time in a shadow-evaporated InAs weak link
• Many-body quantum dynamics of spin-orbit coupled Andreev states in a Zeeman field
• Generalized transmon Hamiltonian for Andreev spin qubits
• Microwave Andreev bound state spectroscopy in a semiconductor-based Planar Josephson junction
• Approaching the ultrastrong coupling regime between an Andreev level and a microwave resonator
• Finite Length Effects and Coulomb Interaction in Ge Quantum Well-Based Josephson Junctions Probed with Microwave Spectroscopy
• Slave-spin approach to the Anderson-Josephson quantum dot