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Fluxonium qubit-based hybrid electromechanical system

Roson Nongthombam1,*, Anshika Ranjan2,†, Amarendra K. Sarma1,‡, and Vibhor Singh2,§

  • *Contact author: n.roson@iitg.ac.in
  • †Contact author: anshikar@iisc.ac.in
  • ‡Contact author: aksarma@iitg.ac.in
  • §Contact author: v.singh@iisc.ac.in
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Phys. Rev. A 113, 063707 – Published 3 June, 2026

DOI: https://doi.org/10.1103/mhnl-b2wp

Abstract

Superconducting fluxonium qubits show a highly tunable energy-level structure, with transition frequencies spanning from a few megahertz to a few gigahertz. This range is well aligned with the operational frequencies of highly coherent micro- and nanomechanical resonators, making fluxonium an attractive candidate for hybrid electromechanical systems. In this work we theoretically investigate a flux-tunable electromechanical system consisting of a fluxonium qubit coupled to a suspended mechanical resonator. The coupling arises from the motion-induced modulation of magnetic flux through the fluxonium loop, enabling both transverse and longitudinal electromechanical interactions that are tunable via external magnetic fields. By optimizing the design parameters of the fluxonium qubit, we demonstrate the feasibility of achieving strong resonant single-photon coupling near the flux-frustration point. We analyze the system dynamics across different coupling regimes, identifying signatures of electromagnetically induced transparency in the longitudinal regime and mode splitting in the transverse regime. Additionally, we show that ground-state preparation of both subsystems is possible through sideband cooling of the mechanical resonator. These results suggest that a fluxonium-based hybrid electromechanical device could be a promising platform for studying macroscopic quantum phenomena and for applications in quantum technology.

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Phys. Rev. A 113, 063707– Published 3 June, 2026
  • Received 27 August 2025
  • Accepted 18 May 2026
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