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:1604.01834 · Physical review. B./Physical review. B

Quartz-superconductor quantum electromechanical system

M. J. Woolley, Muhammad F. Emzir, Gerard J Milburn, Markus Jerger, Maxim Goryachev, Michael Edmund Tobar, Arkady Fedorov

Published Jun 28, 2016• 10 citations
arXivHTMLPDF

Abstract

We propose and analyze a quantum electromechanical system composed of a monolithic quartz bulk acoustic wave oscillator coupled to a superconducting transmon qubit via an intermediate $LC$ electrical circuit. Monolithic quartz oscillators offer unprecedentedly high effective masses and quality factors for the investigation of mechanical oscillators in the quantum regime. Ground-state cooling of such mechanical modes via resonant piezoelectric coupling to an $LC$ circuit, which is itself sideband cooled via coupling to a transmon qubit, is shown to be feasible. The fluorescence spectrum of the qubit, containing motional sideband contributions due to the couplings to the oscillator modes, is obtained and the imprint of the electromechanical steady state on the spectrum is determined. This allows the qubit to function both as a cooling resource for, and transducer of, the mechanical oscillator. The results described are relevant to any hybrid quantum system composed of a qubit coupled to two (coupled or uncoupled) thermal oscillator modes.

DOI
10.1103/physrevb.93.224518

Related papers

Interfacing planar superconducting qubits with high overtone bulk acoustic phonons

Mikael Kervinen, Ilkka Rissanen, Mika A. Sillanpää

Mechanical resonators are a promising way for interfacing qubits in order to realize hybrid quantum systems that offer great possibilities for applications. Mechanical systems can have very long energy lifetimes, and they can be further interfaced to other systems. Moreover, integration of a mechanical oscillator with qubits creates a potential platform for the exploration of quantum physics in macroscopic mechanical degrees of freedom. The utilization of high overtone bulk acoustic resonators coupled to superconducting qubits is an intriguing platform towards these goals. These resonators exhibit a combination of high-frequency and high-quality factors. They can reach their quantum ground state at dilution refrigeration temperatures and they can be strongly coupled to superconducting qubits via their piezoelectric effect. In this paper, we demonstrate our system where bulk acoustic phonons of a high overtone resonator are coupled to a transmon qubit in a planar circuit architecture. We show that the bulk acoustic phonons are interacting with the qubit in a simple design architecture at the quantum level, representing further progress towards the quantum control of mechanical motion.

arXiv:1802.06642•Physical review. B./Physical review. B•May 29, 2018•47 citations

Quartz Mechanical Resonators for Circuit Quantum Acoustics

Emser, Alec L.

Hybrid systems that couple superconducting qubits to mechanical oscillators facilitate quantum control of individual phonons and have the potential to enable compact, highly coherent quantum memories and processors. To date, however, the utility of hybrid quantum acoustic devices has been limited by poor qubit and mechanical coherence times that are far shorter than those exhibited by their unhybridized counterparts. A primary challenge lies in the intrinsic nature of elastic waves in solids: the slow speed of sound results in a dense spectrum of acoustic modes, making it difficult to prevent spontaneous emission of the qubit into phononic degrees of freedom. In this thesis, I will present a systematic effort to suppress loss mechanisms in superconducting qubits and mechanical resonators in the context of circuit quantum acoustics. I begin by demonstrating the use of crystallographic orientation optimization to passively suppress diffraction losses in narrow-aperture quartz surface acoustic wave (SAW) resonators. We then study the coupling of SAW resonators to a quasi-continuum of bulk acoustic modes; this motivates us to abandon bulk piezoelectric media in favor of bandgap-protected thin-film devices. By fabricating suspended phononic crystal resonators from thin-film quartz, we demonstrate an order-of-magnitude improvement in the coherence of this class of devices. I conclude by presenting preliminary measurements of a new flip-chip architecture for circuit quantum acoustics -- the `acoustic trampoline' -- that is designed to maximize qubit-mechanical coupling while simultaneously suppressing spontaneous acoustic emission.

•Apr 17, 2025•0 citations

Measurements of a quantum bulk acoustic resonator using a superconducting qubit

M.-H. Chou, Étienne Dumur, Youpeng Zhong +8 more

Phonon modes at microwave frequencies can be cooled to their quantum ground state using conventional cryogenic refrigeration, providing a convenient way to study and manipulate quantum states at the single phonon level. Phonons are of particular interest because mechanical deformations can mediate interactions with a wide range of different quantum systems, including solid-state defects, superconducting qubits, and optical photons when using optomechanically active constructs. Phonons, thus, hold promise for quantum-focused applications as diverse as sensing, information processing, and communication. Here, we describe a piezoelectric quantum bulk acoustic resonator (QBAR) with a 4.88 GHz resonant frequency, which, at cryogenic temperatures, displays large electromechanical coupling strength combined with a high intrinsic mechanical quality factor, Qi≈4.3×104. Using a recently developed flip-chip technique, we couple this QBAR resonator to a superconducting qubit on a separate die and demonstrate the quantum control of the mechanics in the coupled system. This approach promises a facile and flexible experimental approach to quantum acoustics and hybrid quantum systems.

arXiv:2012.04583•Applied Physics Letters•Dec 21, 2020•15 citations

Piezosähköiset värähtelijät kvanttialueella

Välimaa, Alpo

Acoustic modes—in the form of collective vibrations trapped between the parallel and polished surfaces of a crystalline cavity—provide an intriguing opportunity for probing the quantum-mechanical regime of macroscopical mechanical resonators. Moreover, the exceptional quality factors in a compact size from mm to μm motivate the integration of acoustic resonators into quantum circuits to explore the applications of a quantum hybrid system.While the acoustic modes of a crystal are commonly isolated from electrical dynamics, piezoelectricityis employed to transduce energy between the two domains. In the first part of this thesis, we investigate the means to improve the quality factor of a low frequency plano-convex monolithic quartz resonator. The resonator is 7mm indiameter and 250 μm in thickness, made only of only piezoelectric crystalline material. By the removal of clamping losses and incorporating a distant non-contact measurement setup,we demonstrate quality factors as high as 108 at cryogenic temperatures close to the quantumground state. Additionally, we model the electromechanical clamping losses of a particular grounding setup using temperature-dependent data and the acoustic transmission line based Mason’s model. In the latter part of this thesis, we couple a bulk acoustic high-overtone resonator (HBAR) with a transmon qubit. The electrical actuation of GHz-frequency sound in a HBAR is based on a μm-thin piezo film grown on a low-loss crystalline non-piezo bulk substrate. With an analogy to an acoustic musical instrument, the driven oscillations are amplified at the resonant frequencies of the acoustic cavity, with the addition that a small subset of such modes are selectively listened by the qubit. By the introduction of the acoustic overtones, high quality factors are accessible at the high frequencies of a transmon qubit,while the coupling between the two systems is distributed over the multitude of modes. I model this coupling in detail with respect to the system parameters for guiding the design of related quantum acoustic devices. I cover several different parameter regimes and explore the rich physics taking place in the multimodal hybrid system: Landau-Zener Stuckelberg interference, photon assisted sideband transitions and parametrically modulated coupling that involve the resonant periodical exchange of energy quanta known as vacuum Rabi oscillations, and drive-dependent multiphonon transitions. Despite the otherwise common difficulty to observe quantum mechanics in a harmonic oscillator, we observe purely quantum mechanical effects in the macroscopic resonator, such as a specific square root dependence of the transition energies on the quantum number.

•Jan 1, 2022•10 citations

Quantum State Engineering with Circuit Electromechanical Three-Body Interactions

Mehdi Abdi, Matthias Pernpeintner, Rudolf Groß +2 more

We propose a hybrid system with quantum mechanical three-body interactions between photons, phonons, and qubit excitations. These interactions take place in a circuit quantum electrodynamical architecture with a superconducting microwave resonator coupled to a transmon qubit whose shunt capacitance is free to mechanically oscillate. We show that this system design features a three-mode polariton-mechanical mode and a nonlinear transmon-mechanical mode interaction in the strong coupling regime. Together with the strong resonator-transmon interaction, these properties provide intriguing opportunities for manipulations of this hybrid quantum system. We show, in particular, the feasibility of cooling the mechanical motion down to its ground state and preparing various nonclassical states including mechanical Fock and cat states and hybrid tripartite entangled states.

arXiv:1502.03787•Physical Review Letters•Apr 28, 2015•49 citations

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
We propose and analyze a quantum electromechanical system composed of a monolithic quartz bulk acoustic wave oscillator coupled to a superconducting transmon qubit via an intermediate LCLCLC electrical circuit. Monolithic quartz oscillators offer unprecedentedly high effective masses and quality factors for the investigation of mechanical oscillators in the quantum regime. Ground-state cooling of such mechanical modes via resonant piezoelectric coupling to an LCLCLC circuit, which is itself sideband cooled via coupling to a transmon qubit, is shown to be feasible. The fluorescence spectrum of the qubit, containing motional sideband contributions due to the couplings to the oscillator modes, is obtained and the imprint of the electromechanical steady state on the spectrum is determined. This allows the qubit to function both as a cooling resource for, and transducer of, the mechanical oscillator. The results described are relevant to any hybrid quantum system composed of a qubit coupled to two (coupled or uncoupled) thermal oscillator modes.
Mechanical resonators are a promising way for interfacing qubits in order to realize hybrid quantum systems that offer great possibilities for applications. Mechanical systems can have very long energy lifetimes, and they can be further interfaced to other systems. Moreover, integration of a mechanical oscillator with qubits creates a potential platform for the exploration of quantum physics in macroscopic mechanical degrees of freedom. The utilization of high overtone bulk acoustic resonators coupled to superconducting qubits is an intriguing platform towards these goals. These resonators exhibit a combination of high-frequency and high-quality factors. They can reach their quantum ground state at dilution refrigeration temperatures and they can be strongly coupled to superconducting qubits via their piezoelectric effect. In this paper, we demonstrate our system where bulk acoustic phonons of a high overtone resonator are coupled to a transmon qubit in a planar circuit architecture. We show that the bulk acoustic phonons are interacting with the qubit in a simple design architecture at the quantum level, representing further progress towards the quantum control of mechanical motion.
Hybrid systems that couple superconducting qubits to mechanical oscillators facilitate quantum control of individual phonons and have the potential to enable compact, highly coherent quantum memories and processors. To date, however, the utility of hybrid quantum acoustic devices has been limited by poor qubit and mechanical coherence times that are far shorter than those exhibited by their unhybridized counterparts. A primary challenge lies in the intrinsic nature of elastic waves in solids: the slow speed of sound results in a dense spectrum of acoustic modes, making it difficult to prevent spontaneous emission of the qubit into phononic degrees of freedom. In this thesis, I will present a systematic effort to suppress loss mechanisms in superconducting qubits and mechanical resonators in the context of circuit quantum acoustics. I begin by demonstrating the use of crystallographic orientation optimization to passively suppress diffraction losses in narrow-aperture quartz surface acoustic wave (SAW) resonators. We then study the coupling of SAW resonators to a quasi-continuum of bulk acoustic modes; this motivates us to abandon bulk piezoelectric media in favor of bandgap-protected thin-film devices. By fabricating suspended phononic crystal resonators from thin-film quartz, we demonstrate an order-of-magnitude improvement in the coherence of this class of devices. I conclude by presenting preliminary measurements of a new flip-chip architecture for circuit quantum acoustics -- the `acoustic trampoline' -- that is designed to maximize qubit-mechanical coupling while simultaneously suppressing spontaneous acoustic emission.
Phonon modes at microwave frequencies can be cooled to their quantum ground state using conventional cryogenic refrigeration, providing a convenient way to study and manipulate quantum states at the single phonon level. Phonons are of particular interest because mechanical deformations can mediate interactions with a wide range of different quantum systems, including solid-state defects, superconducting qubits, and optical photons when using optomechanically active constructs. Phonons, thus, hold promise for quantum-focused applications as diverse as sensing, information processing, and communication. Here, we describe a piezoelectric quantum bulk acoustic resonator (QBAR) with a 4.88 GHz resonant frequency, which, at cryogenic temperatures, displays large electromechanical coupling strength combined with a high intrinsic mechanical quality factor, Qi≈4.3×104. Using a recently developed flip-chip technique, we couple this QBAR resonator to a superconducting qubit on a separate die and demonstrate the quantum control of the mechanics in the coupled system. This approach promises a facile and flexible experimental approach to quantum acoustics and hybrid quantum systems.
Acoustic modes—in the form of collective vibrations trapped between the parallel and polished surfaces of a crystalline cavity—provide an intriguing opportunity for probing the quantum-mechanical regime of macroscopical mechanical resonators. Moreover, the exceptional quality factors in a compact size from mm to μm motivate the integration of acoustic resonators into quantum circuits to explore the applications of a quantum hybrid system.While the acoustic modes of a crystal are commonly isolated from electrical dynamics, piezoelectricityis employed to transduce energy between the two domains. In the first part of this thesis, we investigate the means to improve the quality factor of a low frequency plano-convex monolithic quartz resonator. The resonator is 7mm indiameter and 250 μm in thickness, made only of only piezoelectric crystalline material. By the removal of clamping losses and incorporating a distant non-contact measurement setup,we demonstrate quality factors as high as 108 at cryogenic temperatures close to the quantumground state. Additionally, we model the electromechanical clamping losses of a particular grounding setup using temperature-dependent data and the acoustic transmission line based Mason’s model. In the latter part of this thesis, we couple a bulk acoustic high-overtone resonator (HBAR) with a transmon qubit. The electrical actuation of GHz-frequency sound in a HBAR is based on a μm-thin piezo film grown on a low-loss crystalline non-piezo bulk substrate. With an analogy to an acoustic musical instrument, the driven oscillations are amplified at the resonant frequencies of the acoustic cavity, with the addition that a small subset of such modes are selectively listened by the qubit. By the introduction of the acoustic overtones, high quality factors are accessible at the high frequencies of a transmon qubit,while the coupling between the two systems is distributed over the multitude of modes. I model this coupling in detail with respect to the system parameters for guiding the design of related quantum acoustic devices. I cover several different parameter regimes and explore the rich physics taking place in the multimodal hybrid system: Landau-Zener Stuckelberg interference, photon assisted sideband transitions and parametrically modulated coupling that involve the resonant periodical exchange of energy quanta known as vacuum Rabi oscillations, and drive-dependent multiphonon transitions. Despite the otherwise common difficulty to observe quantum mechanics in a harmonic oscillator, we observe purely quantum mechanical effects in the macroscopic resonator, such as a specific square root dependence of the transition energies on the quantum number.
We propose a hybrid system with quantum mechanical three-body interactions between photons, phonons, and qubit excitations. These interactions take place in a circuit quantum electrodynamical architecture with a superconducting microwave resonator coupled to a transmon qubit whose shunt capacitance is free to mechanically oscillate. We show that this system design features a three-mode polariton-mechanical mode and a nonlinear transmon-mechanical mode interaction in the strong coupling regime. Together with the strong resonator-transmon interaction, these properties provide intriguing opportunities for manipulations of this hybrid quantum system. We show, in particular, the feasibility of cooling the mechanical motion down to its ground state and preparing various nonclassical states including mechanical Fock and cat states and hybrid tripartite entangled states.
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.