Controlling the Josephson Potential of a Hybrid Nanowire Fluxonium Qubit - Part I

Hybrid superconducting qubits have emerged as a promising route to extend the tunability and functionality of conventional superconducting circuits. We explore a hybrid gated fluxonium qubit that integrates a conventional Josephson junction array composed of superconductor–insulator–superconductor (S-I-S) junctions with a gate-tunable nanowire-based superconductor–semiconductor–superconductor (S-Sm-S) junction as the main Josephson element. This configuration provides in situ tunability of both the flux through the loop and the Josephson energy via electrostatic gating. In this first talk, we discuss the theoretical framework and design considerations of the hybrid system, including circuit modeling, energy spectra, and the interplay between flux and charge degrees of freedom introduced by the S-Sm-S junction. The dual tunability of this architecture opens a pathway to explore new regimes in fluxonium dynamics and hybrid superconducting qubits.