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

IEEE MTT-S International Microwave Symposium digest

Surface Acoustic Wave Filters for Superconducting Qubits

David Eslava, Eloi Guerrero, Lluís Acosta, Ramiro Sagastizabal, Paul Jamet, P. Forn-Díaz, Pedro de Paco

Published Jun 11, 2023• 0 citations
Publisher

Abstract

In an open system, the dynamical evolution of a qubit state is non-deterministic due to stochastic noise, leading to qubit state decoherence. In the case of the dispersive circuit-QED qubit readout circuit, even when the readout resonator is far off-resonance, the qubit is still damped to some degree, causing decoherence. By using a Purcell filter, qubit loss may be reduced by several orders of magnitude.In this work, we propose to use acoustic wave filters, well-established in the Telecommunications industry, as a Purcell filter. Using acoustic wave filters, like bulk acoustic wave (BAW) or surface acoustic wave (SAW), versus the current state-of-the-art Purcell filters would provide several advantages: higher isolation of the qubit to the readout frequencies as well as being quite miniaturized compared to usual filter alternatives.In this work, we characterize a 1.5GHz LiNbO SAW resonator. The characteization is done maintaining qubit environmental conditions of single photon-level powers and milikelvin temperatures. We characterize its frequency and internal quality factor dependence on temperature and drive power.

DOI
10.1109/ims37964.2023.10188070

Related papers

Mechanical Purcell filters for microwave quantum machines

Agnetta Y. Cleland, Marek Pechal, Pieter-Jan Stas +3 more

In circuit quantum electrodynamics, measuring the state of a superconducting qubit introduces a loss channel, which can enhance spontaneous emission through the Purcell effect, thus decreasing the qubit lifetime. This decay can be mitigated by performing the measurement through a Purcell filter, which strongly suppresses signal propagation at the qubit transition frequency. If the filter is also well-matched at the readout cavity frequency, it will protect the qubit from decoherence channels without sacrificing measurement bandwidth. We propose and analyze design for a mechanical Purcell filter, which we also fabricate and characterize at room temperature. The filter is composed of an array of nanomechanical resonators in thin-film lithium niobate, connected in a ladder topology, with series and parallel resonances arranged to produce a bandpass response. Their modest footprint, steep band edges, and lack of cross talk make these filters an appealing alternative to analogous electromagnetic versions currently used in microwave quantum machines.

arXiv:1905.08403•Applied Physics Letters•Dec 23, 2019•13 citations

Decoherence of surface phonons in a quantum acoustic system

C. Undershute, J. M. Kitzman, Camille A. Mikolas +1 more

Phononic resonators are becoming increasingly important in quantum information science, both for applications in quantum computing, communication, and sensing as well as in experiments investigating fundamental physics. Here, we study the decoherence of phonons confined in a surface acoustic wave (SAW) resonator strongly coupled $(g/2\ensuremath{\pi}\ensuremath{\approx}9\phantom{\rule{0.16em}{0ex}}\mathrm{MHz})$ to a superconducting transmon qubit. By comparing experimental data with numerical solutions to the Markovian master equation, we report a surface phononic energy decay rate of ${\ensuremath{\kappa}}_{1}/2\ensuremath{\pi}=480\phantom{\rule{0.16em}{0ex}}\mathrm{kHz}$ and a pure dephasing rate of ${\ensuremath{\kappa}}_{\ensuremath{\phi}}/2\ensuremath{\pi}=180\phantom{\rule{0.16em}{0ex}}\mathrm{kHz}$. These rates are in good agreement with the level of decoherence we extract from qubit-assisted spectroscopic measurements of the SAW resonator. We additionally find that the timescales over which coherent driven dynamics and decoherence occur are comparable, highlighting the need to model the composite device as an open quantum system. We discuss possible sources of decoherence in SAW-based quantum acoustic devices and the application of these devices in future quantum acoustic dissipation engineering experiments. The decoherence characterization techniques we employ are broadly applicable for investigating and benchmarking the effects of loss and dephasing on mechanical resonators in the quantum regime.

arXiv:2410.03005•Physical Review A•Jan 13, 2025•4 citations

Quantum acoustics with superconducting circuits

Gustav Andersson

The past 20 years has seen rapid developments in circuit quantum electrodynamics, where superconducting qubits and resonators are used to control and study quantum light-matter interaction at a fundamental level. The development of this field is strongly influenced by quantum information science and the prospect of realizing quantum computation, but also opens up opportunities for combinations of different physical systems and research areas. Superconducting circuits in the microwave domain offer a versatile platform for interfacing with other quantum systems thanks to strong nonlinearities and zero-point fluctuations, as well as flexibility in design and fabrication. Hybrid quantum systems based on circuit quantum electrodynamics could enable novel functionalities by exploiting the strengths of the individual components.This thesis covers experiments coupling superconducting circuits to surface acoustic waves (SAWs), mechanical waves propagating along the surface of a solid. Strong coupling can be engineered using the piezoelectric properties of GaAs substrates, and our experiments exploit this to investigate phenomena in quantum field-matter interaction. A key property of surface acoustic waves is the slow propagation speed, typically five orders of magnitude slower than light in vacuum, and the associated short wavelength. This enables the giant atom regime where the artificial atom in the form of a superconducting circuit is large compared to the wavelength of interacting SAW radiation, a condition which is difficult to realize in other systems. Experiments described in this thesis use these properties to demonstrate electromagnetically induced transparency for a mechanical mode, as well as non-Markovian interactions between an artificial giant atom and the SAW field. When the SAW field is confined to a resonant cavity, the short wavelength allows multimode spectra suitable for interacting with a frequency comb. We use a multimode SAW resonator to characterize the ensemble of microscopic two-level system defects with a two-tone spectroscopy approach. Finally, we introduce a hybrid superconducting-SAW resonator with applications in quantum information processing in mind. Experiments with this device demonstrate entanglement of SAW modes, and show promising results on the way to engineer cluster states for quantum computation in continuous variables.

•Jan 1, 2020•0 citations

High-suppression-ratio and wide bandwidth four-stage Purcell filter for multiplexed superconducting qubit readout

Yibiao Zhou, Xiao Cai, Yuzhen Zheng +4 more

Purcell filters, which serve to suppress electromagnetic radiation and enhance the readout efficiency of qubit, are an indispensable component in superconducting quantum chips. With the increasing scale of quantum chips, the requirements for the performance and scalability of Purcell filters are becoming more stringent. In this report, a novel four-stage Purcell filter that enables fast measurement without exacerbating environmental damping of the qubits is presented. The design approach of the filter is derived from the serial and parallel configurations of λ/4 resonant cavities. The filter exhibits exceptional passband-to-stopband isolation, reaching up to 40 dB of isolation within the transition range of 400 MHz. Furthermore, the filter boasts a wide bandwidth for both the stopband and the passband, with the stopband ranging from 4 to 5.5 GHz and the passband extending from 5.8 to 6.5 GHz. In terms of spatial arrangement, each filter can be connected to over ten readout resonators for qubit readout. This innovative Purcell filter will significantly contribute to the development of high quality, scalable superconducting quantum chips.

Journal of Applied Physics•Jan 8, 2024•5 citations

Photon-Noise-Tolerant Dispersive Readout of a Superconducting Qubit Using a Nonlinear Purcell Filter

Yoshiki Sunada, Kenshi Yuki, Zhiling Wang +7 more

Residual noise photons in a readout resonator become a major source of dephasing for a superconducting qubit when the resonator is optimized for a fast, high-fidelity dispersive readout. Here, we propose and demonstrate a nonlinear Purcell filter that suppresses such an undesirable dephasing process without sacrificing the readout performance. When a readout pulse is applied, the filter automatically reduces the effective linewidth of the readout resonator, increasing the sensitivity of the qubit to the input field. The noise tolerance of the device we have fabricated is shown to be enhanced by a factor of 3 relative to a device with a linear filter. The measurement rate is enhanced by another factor of 3 by utilizing the bifurcation of the nonlinear filter. A readout fidelity of 99.4% and a quantum nondemolition fidelity of 99.2% are achieved using a 40-ns readout pulse. The nonlinear Purcell filter will be an effective tool for realizing a fast, high-fidelity readout without compromising the coherence time of the qubit. Published by the American Physical Society 2024

arXiv:2309.04315•PRX Quantum•Jan 19, 2024•33 citations

Surface acoustic wave resonators in the quantum regime

Riccardo Manenti, Michael Peterer, Ani Nersisyan +3 more

We present systematic measurements of the quality factors of surface acoustic wave (SAW) resonators on ST-X quartz in the gigahertz range at a temperature of $10\phantom{\rule{0.16em}{0ex}}\mathrm{mK}$. We demonstrate an internal quality factor ${Q}_{\mathrm{i}}$ approaching $0.5$ million at $0.5\phantom{\rule{0.16em}{0ex}}\text{GHz}$ and show that ${Q}_{\mathrm{i}}\ensuremath{\ge}4.0\ifmmode\times\else\texttimes\fi{}{10}^{4}$ is achievable up to $4.4\phantom{\rule{0.16em}{0ex}}\text{GHz}$. We show evidence for a polynomial dependence of propagation loss on frequency, as well as a weak drive power dependence of ${Q}_{\mathrm{i}}$ that saturates at low power, the latter being consistent with coupling to a bath of two-level systems. Our results indicate that SAW resonators are promising devices for integration with superconducting quantum circuits.

arXiv:1510.04965•Physical review. B./Physical review. B•Jan 15, 2016•129 citations
In an open system, the dynamical evolution of a qubit state is non-deterministic due to stochastic noise, leading to qubit state decoherence. In the case of the dispersive circuit-QED qubit readout circuit, even when the readout resonator is far off-resonance, the qubit is still damped to some degree, causing decoherence. By using a Purcell filter, qubit loss may be reduced by several orders of magnitude.In this work, we propose to use acoustic wave filters, well-established in the Telecommunications industry, as a Purcell filter. Using acoustic wave filters, like bulk acoustic wave (BAW) or surface acoustic wave (SAW), versus the current state-of-the-art Purcell filters would provide several advantages: higher isolation of the qubit to the readout frequencies as well as being quite miniaturized compared to usual filter alternatives.In this work, we characterize a 1.5GHz LiNbO SAW resonator. The characteization is done maintaining qubit environmental conditions of single photon-level powers and milikelvin temperatures. We characterize its frequency and internal quality factor dependence on temperature and drive power.
In circuit quantum electrodynamics, measuring the state of a superconducting qubit introduces a loss channel, which can enhance spontaneous emission through the Purcell effect, thus decreasing the qubit lifetime. This decay can be mitigated by performing the measurement through a Purcell filter, which strongly suppresses signal propagation at the qubit transition frequency. If the filter is also well-matched at the readout cavity frequency, it will protect the qubit from decoherence channels without sacrificing measurement bandwidth. We propose and analyze design for a mechanical Purcell filter, which we also fabricate and characterize at room temperature. The filter is composed of an array of nanomechanical resonators in thin-film lithium niobate, connected in a ladder topology, with series and parallel resonances arranged to produce a bandpass response. Their modest footprint, steep band edges, and lack of cross talk make these filters an appealing alternative to analogous electromagnetic versions currently used in microwave quantum machines.
Phononic resonators are becoming increasingly important in quantum information science, both for applications in quantum computing, communication, and sensing as well as in experiments investigating fundamental physics. Here, we study the decoherence of phonons confined in a surface acoustic wave (SAW) resonator strongly coupled $(g/2\ensuremath{\pi}\ensuremath{\approx}9\phantom{\rule{0.16em}{0ex}}\mathrm{MHz})$ to a superconducting transmon qubit. By comparing experimental data with numerical solutions to the Markovian master equation, we report a surface phononic energy decay rate of ${\ensuremath{\kappa}}_{1}/2\ensuremath{\pi}=480\phantom{\rule{0.16em}{0ex}}\mathrm{kHz}$ and a pure dephasing rate of ${\ensuremath{\kappa}}_{\ensuremath{\phi}}/2\ensuremath{\pi}=180\phantom{\rule{0.16em}{0ex}}\mathrm{kHz}$. These rates are in good agreement with the level of decoherence we extract from qubit-assisted spectroscopic measurements of the SAW resonator. We additionally find that the timescales over which coherent driven dynamics and decoherence occur are comparable, highlighting the need to model the composite device as an open quantum system. We discuss possible sources of decoherence in SAW-based quantum acoustic devices and the application of these devices in future quantum acoustic dissipation engineering experiments. The decoherence characterization techniques we employ are broadly applicable for investigating and benchmarking the effects of loss and dephasing on mechanical resonators in the quantum regime.
The past 20 years has seen rapid developments in circuit quantum electrodynamics, where superconducting qubits and resonators are used to control and study quantum light-matter interaction at a fundamental level. The development of this field is strongly influenced by quantum information science and the prospect of realizing quantum computation, but also opens up opportunities for combinations of different physical systems and research areas. Superconducting circuits in the microwave domain offer a versatile platform for interfacing with other quantum systems thanks to strong nonlinearities and zero-point fluctuations, as well as flexibility in design and fabrication. Hybrid quantum systems based on circuit quantum electrodynamics could enable novel functionalities by exploiting the strengths of the individual components.This thesis covers experiments coupling superconducting circuits to surface acoustic waves (SAWs), mechanical waves propagating along the surface of a solid. Strong coupling can be engineered using the piezoelectric properties of GaAs substrates, and our experiments exploit this to investigate phenomena in quantum field-matter interaction. A key property of surface acoustic waves is the slow propagation speed, typically five orders of magnitude slower than light in vacuum, and the associated short wavelength. This enables the giant atom regime where the artificial atom in the form of a superconducting circuit is large compared to the wavelength of interacting SAW radiation, a condition which is difficult to realize in other systems. Experiments described in this thesis use these properties to demonstrate electromagnetically induced transparency for a mechanical mode, as well as non-Markovian interactions between an artificial giant atom and the SAW field. When the SAW field is confined to a resonant cavity, the short wavelength allows multimode spectra suitable for interacting with a frequency comb. We use a multimode SAW resonator to characterize the ensemble of microscopic two-level system defects with a two-tone spectroscopy approach. Finally, we introduce a hybrid superconducting-SAW resonator with applications in quantum information processing in mind. Experiments with this device demonstrate entanglement of SAW modes, and show promising results on the way to engineer cluster states for quantum computation in continuous variables.
Purcell filters, which serve to suppress electromagnetic radiation and enhance the readout efficiency of qubit, are an indispensable component in superconducting quantum chips. With the increasing scale of quantum chips, the requirements for the performance and scalability of Purcell filters are becoming more stringent. In this report, a novel four-stage Purcell filter that enables fast measurement without exacerbating environmental damping of the qubits is presented. The design approach of the filter is derived from the serial and parallel configurations of λ/4 resonant cavities. The filter exhibits exceptional passband-to-stopband isolation, reaching up to 40 dB of isolation within the transition range of 400 MHz. Furthermore, the filter boasts a wide bandwidth for both the stopband and the passband, with the stopband ranging from 4 to 5.5 GHz and the passband extending from 5.8 to 6.5 GHz. In terms of spatial arrangement, each filter can be connected to over ten readout resonators for qubit readout. This innovative Purcell filter will significantly contribute to the development of high quality, scalable superconducting quantum chips.
Residual noise photons in a readout resonator become a major source of dephasing for a superconducting qubit when the resonator is optimized for a fast, high-fidelity dispersive readout. Here, we propose and demonstrate a nonlinear Purcell filter that suppresses such an undesirable dephasing process without sacrificing the readout performance. When a readout pulse is applied, the filter automatically reduces the effective linewidth of the readout resonator, increasing the sensitivity of the qubit to the input field. The noise tolerance of the device we have fabricated is shown to be enhanced by a factor of 3 relative to a device with a linear filter. The measurement rate is enhanced by another factor of 3 by utilizing the bifurcation of the nonlinear filter. A readout fidelity of 99.4% and a quantum nondemolition fidelity of 99.2% are achieved using a 40-ns readout pulse. The nonlinear Purcell filter will be an effective tool for realizing a fast, high-fidelity readout without compromising the coherence time of the qubit. Published by the American Physical Society 2024
We present systematic measurements of the quality factors of surface acoustic wave (SAW) resonators on ST-X quartz in the gigahertz range at a temperature of 10mK10\phantom{\rule{0.16em}{0ex}}\mathrm{mK}10mK. We demonstrate an internal quality factor Qi{Q}_{\mathrm{i}}Qi​ approaching 0.50.50.5 million at 0.5GHz0.5\phantom{\rule{0.16em}{0ex}}\text{GHz}0.5GHz and show that ${Q}_{\mathrm{i}}\ensuremath{\ge}4.0\ifmmode\times\else\texttimes\fi{}{10}^{4}$ is achievable up to 4.4GHz4.4\phantom{\rule{0.16em}{0ex}}\text{GHz}4.4GHz. We show evidence for a polynomial dependence of propagation loss on frequency, as well as a weak drive power dependence of Qi{Q}_{\mathrm{i}}Qi​ that saturates at low power, the latter being consistent with coupling to a bath of two-level systems. Our results indicate that SAW resonators are promising devices for integration with superconducting quantum circuits.