Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:2001.05700 · Communications Physics

Large flux-mediated coupling in hybrid electromechanical system with a transmon qubit

Tanmoy Bera, Sourav Majumder, Sudhir Kumar Sahu, Vibhor Singh

Published Jan 19, 2021• 27 citations
arXivHTMLPDF

Abstract

Abstract Control over the quantum states of a massive oscillator is important for several technological applications and to test the fundamental limits of quantum mechanics. Addition of an internal degree of freedom to the oscillator could be a valuable resource for such control. Recently, hybrid electromechanical systems using superconducting qubits, based on electric-charge mediated coupling, have been quite successful. Here, we show a hybrid device, consisting of a superconducting transmon qubit and a mechanical resonator coupled using the magnetic-flux. The coupling stems from the quantum-interference of the superconducting phase across the tunnel junctions. We demonstrate a vacuum electromechanical coupling rate up to 4 kHz by making the transmon qubit resonant with the readout cavity. Consequently, thermal-motion of the mechanical resonator is detected by driving the hybridized-mode with mean-occupancy well below one photon. By tuning qubit away from the cavity, electromechanical coupling can be enhanced to 40 kHz. In this limit, a small coherent drive on the mechanical resonator results in the splitting of qubit spectrum, and we observe interference signature arising from the Landau-Zener-Stückelberg effect. With improvements in qubit coherence, this system offers a platform to realize rich interactions and could potentially provide full control over the quantum motional states.

DOI
10.1038/s42005-020-00514-y

Related papers

Fluxonium qubit-based hybrid electromechanical system

Roson Nongthombam, Anshika Ranjan, Amarendra K. Sarma +1 more

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 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 (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.

arXiv:2508.17105•Physical Review A•May 18, 2026•0 citations

Fundamentals and Applications of Hybrid Electro- and Opto-mechanical system coupled to Superconducting Qubit: A Short Review

Roson Nongthombam, Urmimala Dewan, Amarendra K. Sarma

Superconducting qubits, realized by incorporating Josephson junctions into superconducting circuits, behave as artificial atoms with anharmonic energy spectra and can be precisely controlled and measured using microwave cavities within the framework of circuit quantum electrodynamics (cQED). Since its emergence in the early 2000s, cQED has established superconducting qubits as leading candidates for scalable quantum devices and has enabled the exploration of hybrid quantum systems that integrate disparate physical platformsThis review surveys superconducting hybrid quantum electromechanical systems in which mechanical resonators are coupled to superconducting qubits, with a focus on two widely used qubit platforms: the transmon and the fluxonium. We provide an overview of the underlying coupling mechanisms arising from interactions through the phase and charge degrees of freedom of the qubit, and discuss how these mechanisms give rise to both longitudinal and transverse qubit-mechanical interactions. We further review extensions of electromechanical platforms to electro-optomechanical architectures, in which optical cavities are integrated to enable coherent interfacing between superconducting circuits and optical photons. This review aims to present a unified framework and perspective on qubit-mechanical and qubit-mechanical-optical hybrid systems in superconducting quantum technologies and applications related to sensors.

quant-pharXiv:2604.18186•Discover Quantum Science•Apr 21, 2026•1 citation

Prospects of cooling a mechanical resonator with a transmon qubit in c-QED setup

Sourav Majumder, Tanmoy Bera, Vibhor Singh

Hybrid devices based on the superconducting qubits have emerged as a promising platform for controlling the quantum states of macroscopic resonators. The nonlinearity added by a qubit can be a valuable resource for such control. Here we study a hybrid system consisting of a mechanical resonator longitudinally coupled to a transmon qubit. The qubit readout can be done by coupling to a readout mode like in c-QED setup. The coupling between the mechanical resonator and transmon qubit can be implemented by the modulation of the superconducting quantum interference device inductance. In such a tripartite system, we analyze the steady-state occupation of the mechanical mode when all three modes are dispersively coupled. We use the quantum noise and the Lindblad formalism to show that the sideband cooling of the mechanical mode to its ground state is achievable. We further experimentally demonstrate that measurements of the thermomechanical motion are possible in the dispersive limit, while maintaining a large coupling between qubit and mechanical mode. Our theoretical calculations suggest that single-photon strong coupling is within the experimental reach in such hybrid devices.

arXiv:2205.07024•Physical Review Research•Sep 23, 2022•1 citation

Measurements of nanoresonator-qubit interactions in a hybrid quantum electromechanical system

Francisco P. M. Rouxinol, Y. Hao, F Brito +3 more

Experiments to probe the basic quantum properties of motional degrees of freedom of mechanical systems have developed rapidly over the last decade. One promising approach is to use hybrid electromechanical systems incorporating superconducting qubits and microwave circuitry. However, a critical challenge facing the development of these systems is to achieve strong coupling between mechanics and qubits while simultaneously reducing coupling of both the qubit and mechanical mode to the environment. Here we report measurements of a qubit-coupled mechanical resonator system consisting of an ultra-high-frequency nanoresonator and a long coherence-time superconducting transmon qubit, embedded in a superconducting coplanar waveguide cavity. It is demonstrated that the nanoresonator and transmon have commensurate energies and transmon coherence times are one order of magnitude larger than for all previously reported qubit-coupled nanoresonators. Moreover, we show that numerical simulations of this new hybrid quantum system are in good agreement with spectroscopic measurements and suggest that the nanoresonator in our device resides at low thermal occupation number, near its ground state, acting as a dissipative bath seen by the qubit. We also outline how this system could soon be developed as a platform for implementing more advanced experiments with direct relevance to quantum information processing and quantum thermodynamics, including the study of nanoresonator quantum noise properties, reservoir engineering, and nanomechanical quantum state generation and detection.

arXiv:1605.01454•Nanotechnology•Aug 2, 2016•52 citations

Landau-Zener-Stückelberg Interference in a Multimode Electromechanical System in the Quantum Regime

Mikael Kervinen, Jhon E. Ramírez-Muñoz, Alpo Välimaa +1 more

The studies of mechanical resonators in the quantum regime not only provide insight into the fundamental nature of quantum mechanics of massive objects, but also introduce promising platforms for novel hybrid quantum technologies. Here we demonstrate a configurable interaction between a superconducting qubit and many acoustic modes in the quantum regime. Specifically, we show how consecutive Landau-Zener-Stückelberg (LZS) tunneling type of transitions, which take place when a system is tuned through an avoided crossing of the coupled energy levels, interfere in a multimode system. The work progresses experimental LZS interference to cover a new class of systems where the coupled levels are those of a quantum two-level system interacting with a multitude of mechanical oscillators. The work opens up applications in controlling multiple acoustic modes via parametric modulation.

arXiv:1909.07679•Physical Review Letters•Dec 12, 2019•31 citations

Coherent Transmon-Charge Qubit Coupling Mediated by Virtual Photon Exchange in a High Impedance Resonator

Pasquale Scarlino, David J. van Woerkom, Udson C. Mendes +9 more

We explore the coupling of the charge degree of freedom of electrons confined in a GaAs/AlGaAs double quantum dot (DQD) to a superconducting transmon qubit in the circuit QED architecture. In this work, we realize a proof of concept experiment in which the coupling between a transmon qubit and a DQD qubit is mediated by virtual microwave photon excitations in a tunable high impedance SQUID array resonator, which acts as a quantum bus enabling long range coupling between dissimilar qubits. Our device hosts a DQD capacitively coupled to a SQUID array resonator, which in turn is coupled to a single island transmon. The device is further equipped with a flux line for fast control of the transmon frequency, and with a 50 Ω CPW resonator capacitively coupled to the transmon for readout. Realizing a well controlled interface between semiconductor and superconductor-based quantum computing architectures will allow to take full advantage of those two solid states quantum systems for hybrid-quantum processors and will enable the use of both charge and flux degrees of freedom in the same device. The methods and techniques developed in this work are expected to be transferable to other material systems.

Bulletin of the American Physical Society•Mar 8, 2018•0 citations
Abstract Control over the quantum states of a massive oscillator is important for several technological applications and to test the fundamental limits of quantum mechanics. Addition of an internal degree of freedom to the oscillator could be a valuable resource for such control. Recently, hybrid electromechanical systems using superconducting qubits, based on electric-charge mediated coupling, have been quite successful. Here, we show a hybrid device, consisting of a superconducting transmon qubit and a mechanical resonator coupled using the magnetic-flux. The coupling stems from the quantum-interference of the superconducting phase across the tunnel junctions. We demonstrate a vacuum electromechanical coupling rate up to 4 kHz by making the transmon qubit resonant with the readout cavity. Consequently, thermal-motion of the mechanical resonator is detected by driving the hybridized-mode with mean-occupancy well below one photon. By tuning qubit away from the cavity, electromechanical coupling can be enhanced to 40 kHz. In this limit, a small coherent drive on the mechanical resonator results in the splitting of qubit spectrum, and we observe interference signature arising from the Landau-Zener-Stückelberg effect. With improvements in qubit coherence, this system offers a platform to realize rich interactions and could potentially provide full control over the quantum motional states.
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 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 (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.
Superconducting qubits, realized by incorporating Josephson junctions into superconducting circuits, behave as artificial atoms with anharmonic energy spectra and can be precisely controlled and measured using microwave cavities within the framework of circuit quantum electrodynamics (cQED). Since its emergence in the early 2000s, cQED has established superconducting qubits as leading candidates for scalable quantum devices and has enabled the exploration of hybrid quantum systems that integrate disparate physical platformsThis review surveys superconducting hybrid quantum electromechanical systems in which mechanical resonators are coupled to superconducting qubits, with a focus on two widely used qubit platforms: the transmon and the fluxonium. We provide an overview of the underlying coupling mechanisms arising from interactions through the phase and charge degrees of freedom of the qubit, and discuss how these mechanisms give rise to both longitudinal and transverse qubit-mechanical interactions. We further review extensions of electromechanical platforms to electro-optomechanical architectures, in which optical cavities are integrated to enable coherent interfacing between superconducting circuits and optical photons. This review aims to present a unified framework and perspective on qubit-mechanical and qubit-mechanical-optical hybrid systems in superconducting quantum technologies and applications related to sensors.
Hybrid devices based on the superconducting qubits have emerged as a promising platform for controlling the quantum states of macroscopic resonators. The nonlinearity added by a qubit can be a valuable resource for such control. Here we study a hybrid system consisting of a mechanical resonator longitudinally coupled to a transmon qubit. The qubit readout can be done by coupling to a readout mode like in c-QED setup. The coupling between the mechanical resonator and transmon qubit can be implemented by the modulation of the superconducting quantum interference device inductance. In such a tripartite system, we analyze the steady-state occupation of the mechanical mode when all three modes are dispersively coupled. We use the quantum noise and the Lindblad formalism to show that the sideband cooling of the mechanical mode to its ground state is achievable. We further experimentally demonstrate that measurements of the thermomechanical motion are possible in the dispersive limit, while maintaining a large coupling between qubit and mechanical mode. Our theoretical calculations suggest that single-photon strong coupling is within the experimental reach in such hybrid devices.
Experiments to probe the basic quantum properties of motional degrees of freedom of mechanical systems have developed rapidly over the last decade. One promising approach is to use hybrid electromechanical systems incorporating superconducting qubits and microwave circuitry. However, a critical challenge facing the development of these systems is to achieve strong coupling between mechanics and qubits while simultaneously reducing coupling of both the qubit and mechanical mode to the environment. Here we report measurements of a qubit-coupled mechanical resonator system consisting of an ultra-high-frequency nanoresonator and a long coherence-time superconducting transmon qubit, embedded in a superconducting coplanar waveguide cavity. It is demonstrated that the nanoresonator and transmon have commensurate energies and transmon coherence times are one order of magnitude larger than for all previously reported qubit-coupled nanoresonators. Moreover, we show that numerical simulations of this new hybrid quantum system are in good agreement with spectroscopic measurements and suggest that the nanoresonator in our device resides at low thermal occupation number, near its ground state, acting as a dissipative bath seen by the qubit. We also outline how this system could soon be developed as a platform for implementing more advanced experiments with direct relevance to quantum information processing and quantum thermodynamics, including the study of nanoresonator quantum noise properties, reservoir engineering, and nanomechanical quantum state generation and detection.
The studies of mechanical resonators in the quantum regime not only provide insight into the fundamental nature of quantum mechanics of massive objects, but also introduce promising platforms for novel hybrid quantum technologies. Here we demonstrate a configurable interaction between a superconducting qubit and many acoustic modes in the quantum regime. Specifically, we show how consecutive Landau-Zener-Stückelberg (LZS) tunneling type of transitions, which take place when a system is tuned through an avoided crossing of the coupled energy levels, interfere in a multimode system. The work progresses experimental LZS interference to cover a new class of systems where the coupled levels are those of a quantum two-level system interacting with a multitude of mechanical oscillators. The work opens up applications in controlling multiple acoustic modes via parametric modulation.
We explore the coupling of the charge degree of freedom of electrons confined in a GaAs/AlGaAs double quantum dot (DQD) to a superconducting transmon qubit in the circuit QED architecture. In this work, we realize a proof of concept experiment in which the coupling between a transmon qubit and a DQD qubit is mediated by virtual microwave photon excitations in a tunable high impedance SQUID array resonator, which acts as a quantum bus enabling long range coupling between dissimilar qubits. Our device hosts a DQD capacitively coupled to a SQUID array resonator, which in turn is coupled to a single island transmon. The device is further equipped with a flux line for fast control of the transmon frequency, and with a 50 Ω CPW resonator capacitively coupled to the transmon for readout. Realizing a well controlled interface between semiconductor and superconductor-based quantum computing architectures will allow to take full advantage of those two solid states quantum systems for hybrid-quantum processors and will enable the use of both charge and flux degrees of freedom in the same device. The methods and techniques developed in this work are expected to be transferable to other material systems.