A fluxonium qubit-based hybrid electromechanical system

TL;DR

This paper theoretically explores a fluxonium qubit coupled to a mechanical resonator, demonstrating tunable strong coupling, EIT signatures, and ground-state cooling, advancing hybrid quantum systems for macroscopic quantum studies.

Contribution

It introduces a fluxonium-based hybrid electromechanical system with tunable interactions and analyzes its dynamics, showing feasibility for strong coupling and quantum control.

Findings

Achieves near-resonant strong single-photon coupling.

Identifies electromagnetically induced transparency (EIT) signatures.

Demonstrates ground-state cooling of the mechanical resonator.

Abstract

Superconducting fluxonium qubits show a highly tunable energy-level structure, with transition frequencies spanning from a few MHz to few GHz. This range is well-aligned to the operational frequencies of highly coherent micro- and nano-mechanical resonators, making fluxonium an at- tractive 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 interac- tions 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 (EIT) 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.