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

Physical Review Applied

Acoustic Radiation From a Superconducting Qubit: From Spontaneous Emission to Rabi Oscillations

Vijay Jain, Vladislav D. Kurilovich, Yanni D. Dahmani, Chan U Lei, David Mason, Taekwan Yoon, Peter T. Rakich, L. I. Glazman, Robert J. Schoelkopf

Published Jul 11, 2023• 12 citations
Publisher

Abstract

A phonon (quantized vibration of a crystalline medium) is much shorter in wavelength than a photon of the same frequency. This length-scale reduction offers an opportunity to achieve higher density of quantum information storage, and may open a path to scalable implementations of superconducting quantum processors. However, the smallness of the acoustic wavelength also poses a challenge: It may result in fast qubit decoherence via an unintentional emission of phonons. The authors demonstrate how to circumvent such spontaneous emission and attain quantum coherent coupling of a qubit to an isolated phonon mode.

DOI
10.1103/physrevapplied.20.014018

Related papers

Acoustic radiation from a superconducting qubit: From spontaneous emission to Rabi oscillations

Vijay Jain, Vladislav D. Kurilovich, Yanni D. Dahmani +6 more

Acoustic spontaneous emission into bulk dielectrics can be a strong source of decoherence in quantum devices, especially when a qubit is in the presence of piezoelectric materials. We study the dynamics of a qubit coupled to an acoustic resonator by a piezoelectric film. By varying the surface topography of the resonator from rough to polished to shaped, we explore the crossover from fast decay of an excited qubit to quantum-coherent coupling between the qubit and an isolated phonon mode. Our experimental approach may be used for precision measurements of crystalline vibrations, the design of quantum memories, and the study of electro-mechanical contributions to dielectric loss.

arXiv:2211.07475•Nov 14, 2022•0 citations

Quantum Acoustics: Propagating phonons coupled to a superconducting qubit

M. Gustafsson, Thomas Aref, Anton Frisk Kockum +3 more

Atoms, ions, and superconducting qubits are all examples of quantum objects, capable of producing and processing individual quanta of light, known as photons. Mechanical movement can be quantized in the same way as light, into particles of vibration known as phonons. Recent experiments have shown that quantum information generated in qubits can be converted to vibrations in mechanical resonators, which resemble miniature drum skins or piano strings. Such resonators restrict motion to their discrete and stationary modes, and thus serve as \emph{local storage units} for phonons. Here, we demonstrate the use of phonons as \emph{propagating carriers} of quantum information, by coupling them strongly to a superconducting qubit. The phonons thus serve the same role as itinerant photons have in the field of quantum optics. Due to the low speed of sound and a potential for very strong coupling, the use of propagating phonons as quantum carriers allows regimes to be explored which are difficult or impossible to reach with photons.

•Apr 1, 2014•5 citations

Good vibrations in quantum communication

Ian S. Osborne

Quantum Physics Quantum information processing platforms typically require qubits to talk to each other. To date, photons (either optical or microwave) have been the carrier of choice to transfer quantum states between the qubits. For some solid-state systems, however, the vibrational properties of the materials themselves, phonons, could be advantageous. Bienfait et al. describe the deterministic emission and capture of itinerant phonons through an acoustic communication channel, enabling the phonon-based coherent transfer of quantum states from one superconducting qubit to another and the quantum entanglement of the two qubits over the acoustic channel. The results provide a route to couple hybrid quantum solid-state systems using surface acoustic waves. Science , this issue p. [368][1] [1]: /lookup/doi/10.1126/science.aaw8415

Science•Apr 25, 2019•0 citations

Circuit Quantum Acoustodynamics in a Scalable Phononic Integrated Circuit Architecture

Weiting Wang, Lintao Xiao, Bo Zhang +11 more

Previous demonstrations of quantum acoustic systems have been limited to isolated devices, with limited capability to route phonons and interconnect multi-port acoustic elements for further extension. Here, we demonstrate a scalable architecture for circuit quantum acoustodynamics (cQAD) by integrating superconducting qubits with suspension-free phononic integrated circuits (PnICs). Coherent coupling between tunable transmon qubits and waveguide-integrated phononic cavities, including Fabry-Perot cavities via monolithic integration and microring cavities via flip-chip assembly, has been achieved, producing a pronounced enhancement of phonon emission with a Purcell factor of ~19. These devices represent elementary building blocks for scalable phononic circuits, establishing the foundation for phonon-based quantum information processors and the testbed for novel quantum acoustic phenomena.

quant-pharXiv:2512.04953•Dec 5, 2025

Resolving Phonon Fock States in a Multimode Cavity with a Double-Slit Qubit

Lucas R. Sletten, Bradley A. Moores, J. J. Viennot +1 more

We resolve phonon number states in the spectrum of a superconducting qubit coupled to a multimode acoustic cavity.Crucial to this resolution is the sharp frequency dependence in the qubit-phonon interaction engineered by coupling the qubit to surface acoustic waves in two locations separated by ∼40 acoustic wavelengths.In analogy to double-slit diffraction, the resulting interference generates high-contrast frequency structure in the qubit-phonon interaction.We observe this frequency structure both in the coupling rate to multiple cavity modes and in the qubit spontaneous emission rate into unconfined modes.We use this sharp frequency structure to resolve single phonons by tuning the qubit to a frequency of destructive interference where all acoustic interactions are dispersive.By exciting several detuned yet strongly coupled phononic modes and measuring the resulting qubit spectrum, we observe that, for two modes, the device enters the strong dispersive regime where single phonons are spectrally resolved.

arXiv:1902.06344•Physical Review X•Jun 20, 2019•117 citations

Beyond spontaneous emission: Giant atom bounded in the continuum

Shangjie Guo, Yidan Wang, Thomas Purdy +1 more

The quantum coupling of individual superconducting qubits to microwave photons leads to remarkable experimental opportunities. Here we consider the phononic case where the qubit is coupled to an electromagnetic surface acoustic wave antenna that enables supersonic (electromagnetic) propagation of the qubit oscillations. This can be considered as a giant atom that is many phonon wavelengths long. We study an exactly solvable toy model that captures these effects, and find that this non-Markovian giant atom has a suppressed relaxation, so long as an effective vacuum coupling exists between a qubit excitation and a localized wave packet of sound, even in the absence of a cavity for the sound waves. Finally, we consider practical implementations of these ideas in current surface acoustic wave devices.

arXiv:1912.09980•Physical Review A•Sep 8, 2020•87 citations
A phonon (quantized vibration of a crystalline medium) is much shorter in wavelength than a photon of the same frequency. This length-scale reduction offers an opportunity to achieve higher density of quantum information storage, and may open a path to scalable implementations of superconducting quantum processors. However, the smallness of the acoustic wavelength also poses a challenge: It may result in fast qubit decoherence via an unintentional emission of phonons. The authors demonstrate how to circumvent such spontaneous emission and attain quantum coherent coupling of a qubit to an isolated phonon mode.
Acoustic spontaneous emission into bulk dielectrics can be a strong source of decoherence in quantum devices, especially when a qubit is in the presence of piezoelectric materials. We study the dynamics of a qubit coupled to an acoustic resonator by a piezoelectric film. By varying the surface topography of the resonator from rough to polished to shaped, we explore the crossover from fast decay of an excited qubit to quantum-coherent coupling between the qubit and an isolated phonon mode. Our experimental approach may be used for precision measurements of crystalline vibrations, the design of quantum memories, and the study of electro-mechanical contributions to dielectric loss.
Atoms, ions, and superconducting qubits are all examples of quantum objects, capable of producing and processing individual quanta of light, known as photons. Mechanical movement can be quantized in the same way as light, into particles of vibration known as phonons. Recent experiments have shown that quantum information generated in qubits can be converted to vibrations in mechanical resonators, which resemble miniature drum skins or piano strings. Such resonators restrict motion to their discrete and stationary modes, and thus serve as \emph{local storage units} for phonons. Here, we demonstrate the use of phonons as \emph{propagating carriers} of quantum information, by coupling them strongly to a superconducting qubit. The phonons thus serve the same role as itinerant photons have in the field of quantum optics. Due to the low speed of sound and a potential for very strong coupling, the use of propagating phonons as quantum carriers allows regimes to be explored which are difficult or impossible to reach with photons.
Quantum Physics Quantum information processing platforms typically require qubits to talk to each other. To date, photons (either optical or microwave) have been the carrier of choice to transfer quantum states between the qubits. For some solid-state systems, however, the vibrational properties of the materials themselves, phonons, could be advantageous. Bienfait et al. describe the deterministic emission and capture of itinerant phonons through an acoustic communication channel, enabling the phonon-based coherent transfer of quantum states from one superconducting qubit to another and the quantum entanglement of the two qubits over the acoustic channel. The results provide a route to couple hybrid quantum solid-state systems using surface acoustic waves. Science , this issue p. [368][1] [1]: /lookup/doi/10.1126/science.aaw8415
Previous demonstrations of quantum acoustic systems have been limited to isolated devices, with limited capability to route phonons and interconnect multi-port acoustic elements for further extension. Here, we demonstrate a scalable architecture for circuit quantum acoustodynamics (cQAD) by integrating superconducting qubits with suspension-free phononic integrated circuits (PnICs). Coherent coupling between tunable transmon qubits and waveguide-integrated phononic cavities, including Fabry-Perot cavities via monolithic integration and microring cavities via flip-chip assembly, has been achieved, producing a pronounced enhancement of phonon emission with a Purcell factor of ~19. These devices represent elementary building blocks for scalable phononic circuits, establishing the foundation for phonon-based quantum information processors and the testbed for novel quantum acoustic phenomena.
We resolve phonon number states in the spectrum of a superconducting qubit coupled to a multimode acoustic cavity.Crucial to this resolution is the sharp frequency dependence in the qubit-phonon interaction engineered by coupling the qubit to surface acoustic waves in two locations separated by ∼40 acoustic wavelengths.In analogy to double-slit diffraction, the resulting interference generates high-contrast frequency structure in the qubit-phonon interaction.We observe this frequency structure both in the coupling rate to multiple cavity modes and in the qubit spontaneous emission rate into unconfined modes.We use this sharp frequency structure to resolve single phonons by tuning the qubit to a frequency of destructive interference where all acoustic interactions are dispersive.By exciting several detuned yet strongly coupled phononic modes and measuring the resulting qubit spectrum, we observe that, for two modes, the device enters the strong dispersive regime where single phonons are spectrally resolved.
The quantum coupling of individual superconducting qubits to microwave photons leads to remarkable experimental opportunities. Here we consider the phononic case where the qubit is coupled to an electromagnetic surface acoustic wave antenna that enables supersonic (electromagnetic) propagation of the qubit oscillations. This can be considered as a giant atom that is many phonon wavelengths long. We study an exactly solvable toy model that captures these effects, and find that this non-Markovian giant atom has a suppressed relaxation, so long as an effective vacuum coupling exists between a qubit excitation and a localized wave packet of sound, even in the absence of a cavity for the sound waves. Finally, we consider practical implementations of these ideas in current surface acoustic wave devices.