Gate-Tunable Field-Compatible Fluxonium

Abstract

Hybrid superconducting circuits, which integrate nonsuperconducting elements into a circuit quantum electrodynamics (cQED) architecture, expand the possible applications of cQED. Building hybrid circuits that work in large magnetic fields presents even further possibilities, such as the probing of spin-polarized Andreev bound states and the investigation of topological superconductivity. Here we present a magnetic-field compatible hybrid fluxonium with an electrostatically tuned semiconducting nanowire as its nonlinear element. We operate the fluxonium in magnetic fields up to 1 T and use it to observe the f0-Josephson effect. This combination of gate tunability and field compatibility opens avenues for the control of spin-polarized phenomena using superconducting circuits and enables the use of the fluxonium as a readout device for topological qubits.