Enhancing Dispersive Readout of Superconducting Qubits through Dynamic Control of the Dispersive Shift: Experiment and Theory

The performance of a wide range of quantum computing algorithms and protocols depends critically on the fidelity and speed of the employed qubit readout. Examples include gate sequences benefiting from midcircuit real-time measurement-based feedback, such as qubit initialization, entanglement genera...

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Main Authors: François Swiadek, Ross Shillito, Paul Magnard, Ants Remm, Christoph Hellings, Nathan Lacroix, Quentin Ficheux, Dante Colao Zanuz, Graham J. Norris, Alexandre Blais, Sebastian Krinner, Andreas Wallraff
Format: Article
Language:English
Published: American Physical Society 2024-11-01
Series:PRX Quantum
Online Access:http://doi.org/10.1103/PRXQuantum.5.040326
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author François Swiadek
Ross Shillito
Paul Magnard
Ants Remm
Christoph Hellings
Nathan Lacroix
Quentin Ficheux
Dante Colao Zanuz
Graham J. Norris
Alexandre Blais
Sebastian Krinner
Andreas Wallraff
author_facet François Swiadek
Ross Shillito
Paul Magnard
Ants Remm
Christoph Hellings
Nathan Lacroix
Quentin Ficheux
Dante Colao Zanuz
Graham J. Norris
Alexandre Blais
Sebastian Krinner
Andreas Wallraff
author_sort François Swiadek
collection DOAJ
description The performance of a wide range of quantum computing algorithms and protocols depends critically on the fidelity and speed of the employed qubit readout. Examples include gate sequences benefiting from midcircuit real-time measurement-based feedback, such as qubit initialization, entanglement generation, teleportation, and, perhaps most importantly, quantum error correction. A prominent and widely used readout approach is based on the dispersive interaction of a superconducting qubit strongly coupled to a large-bandwidth readout resonator, frequently combined with a dedicated or shared Purcell filter protecting qubits from decay. By dynamically reducing the qubit-resonator detuning and thus increasing the dispersive shift, we demonstrate a beyond-state-of-the-art two-state-readout error of only 0.25% in 100-ns integration time. Maintaining low-readout-drive strength, we nearly quadruple the signal-to-noise ratio of the readout by doubling the readout-mode line width, which we quantify by considering the hybridization of the readout resonator and its dedicated Purcell filter. We find excellent agreement between our experimental data and our theoretical model. The presented results are expected to further boost the performance of new and existing algorithms and protocols critically depending on high-fidelity fast midcircuit measurements.
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institution Kabale University
issn 2691-3399
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publishDate 2024-11-01
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spelling doaj-art-c10530e7d0a34438a82ec166a7c2440d2024-11-20T15:11:20ZengAmerican Physical SocietyPRX Quantum2691-33992024-11-015404032610.1103/PRXQuantum.5.040326Enhancing Dispersive Readout of Superconducting Qubits through Dynamic Control of the Dispersive Shift: Experiment and TheoryFrançois SwiadekRoss ShillitoPaul MagnardAnts RemmChristoph HellingsNathan LacroixQuentin FicheuxDante Colao ZanuzGraham J. NorrisAlexandre BlaisSebastian KrinnerAndreas WallraffThe performance of a wide range of quantum computing algorithms and protocols depends critically on the fidelity and speed of the employed qubit readout. Examples include gate sequences benefiting from midcircuit real-time measurement-based feedback, such as qubit initialization, entanglement generation, teleportation, and, perhaps most importantly, quantum error correction. A prominent and widely used readout approach is based on the dispersive interaction of a superconducting qubit strongly coupled to a large-bandwidth readout resonator, frequently combined with a dedicated or shared Purcell filter protecting qubits from decay. By dynamically reducing the qubit-resonator detuning and thus increasing the dispersive shift, we demonstrate a beyond-state-of-the-art two-state-readout error of only 0.25% in 100-ns integration time. Maintaining low-readout-drive strength, we nearly quadruple the signal-to-noise ratio of the readout by doubling the readout-mode line width, which we quantify by considering the hybridization of the readout resonator and its dedicated Purcell filter. We find excellent agreement between our experimental data and our theoretical model. The presented results are expected to further boost the performance of new and existing algorithms and protocols critically depending on high-fidelity fast midcircuit measurements.http://doi.org/10.1103/PRXQuantum.5.040326
spellingShingle François Swiadek
Ross Shillito
Paul Magnard
Ants Remm
Christoph Hellings
Nathan Lacroix
Quentin Ficheux
Dante Colao Zanuz
Graham J. Norris
Alexandre Blais
Sebastian Krinner
Andreas Wallraff
Enhancing Dispersive Readout of Superconducting Qubits through Dynamic Control of the Dispersive Shift: Experiment and Theory
PRX Quantum
title Enhancing Dispersive Readout of Superconducting Qubits through Dynamic Control of the Dispersive Shift: Experiment and Theory
title_full Enhancing Dispersive Readout of Superconducting Qubits through Dynamic Control of the Dispersive Shift: Experiment and Theory
title_fullStr Enhancing Dispersive Readout of Superconducting Qubits through Dynamic Control of the Dispersive Shift: Experiment and Theory
title_full_unstemmed Enhancing Dispersive Readout of Superconducting Qubits through Dynamic Control of the Dispersive Shift: Experiment and Theory
title_short Enhancing Dispersive Readout of Superconducting Qubits through Dynamic Control of the Dispersive Shift: Experiment and Theory
title_sort enhancing dispersive readout of superconducting qubits through dynamic control of the dispersive shift experiment and theory
url http://doi.org/10.1103/PRXQuantum.5.040326
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