Fast and high-fidelity dispersive readout of a spin qubit with squeezed microwave and resonator nonlinearity

Abstract Fast and high-fidelity qubit measurement is essential for quantum error correction in universal quantum computing. This study examines dispersive measurement of a spin in a semiconductor double quantum dot using a nonlinear microwave resonator. By employing displaced squeezed vacuum states,...

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Main Authors: Chon-Fai Kam, Xuedong Hu
Format: Article
Language:English
Published: Nature Portfolio 2024-12-01
Series:npj Quantum Information
Online Access:https://doi.org/10.1038/s41534-024-00924-8
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author Chon-Fai Kam
Xuedong Hu
author_facet Chon-Fai Kam
Xuedong Hu
author_sort Chon-Fai Kam
collection DOAJ
description Abstract Fast and high-fidelity qubit measurement is essential for quantum error correction in universal quantum computing. This study examines dispersive measurement of a spin in a semiconductor double quantum dot using a nonlinear microwave resonator. By employing displaced squeezed vacuum states, we achieve rapid, high-fidelity readout for silicon spin qubits. Our results show that modest squeezing and mild nonlinearity significantly enhance the signal-to-noise ratio (SNR) and the fidelity of qubit-state readout. By optimally adjusting the phases of squeezing and nonlinearity, we reduce readout time to sub-microsecond ranges. With current technology parameters (κ ≈ 2χ s , χ s /(2π) ≈ 0.15 MHz), utilizing a displaced squeezed vacuum state with 30 photons and a modest squeezing parameter r ≈ 0.6, along with a nonlinear microwave resonator charactered by a strength of λ ≈ − 1.2χ s , a readout fidelity of 98% can be attained within a readout time of around 0.6 μs.
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spelling doaj-art-20fa5db1264a401ab2e89b5d1e2f3da02024-12-29T12:39:54ZengNature Portfolionpj Quantum Information2056-63872024-12-0110111110.1038/s41534-024-00924-8Fast and high-fidelity dispersive readout of a spin qubit with squeezed microwave and resonator nonlinearityChon-Fai Kam0Xuedong Hu1Department of Informatics, LMU MunichDepartment of Physics, University at Buffalo, SUNYAbstract Fast and high-fidelity qubit measurement is essential for quantum error correction in universal quantum computing. This study examines dispersive measurement of a spin in a semiconductor double quantum dot using a nonlinear microwave resonator. By employing displaced squeezed vacuum states, we achieve rapid, high-fidelity readout for silicon spin qubits. Our results show that modest squeezing and mild nonlinearity significantly enhance the signal-to-noise ratio (SNR) and the fidelity of qubit-state readout. By optimally adjusting the phases of squeezing and nonlinearity, we reduce readout time to sub-microsecond ranges. With current technology parameters (κ ≈ 2χ s , χ s /(2π) ≈ 0.15 MHz), utilizing a displaced squeezed vacuum state with 30 photons and a modest squeezing parameter r ≈ 0.6, along with a nonlinear microwave resonator charactered by a strength of λ ≈ − 1.2χ s , a readout fidelity of 98% can be attained within a readout time of around 0.6 μs.https://doi.org/10.1038/s41534-024-00924-8
spellingShingle Chon-Fai Kam
Xuedong Hu
Fast and high-fidelity dispersive readout of a spin qubit with squeezed microwave and resonator nonlinearity
npj Quantum Information
title Fast and high-fidelity dispersive readout of a spin qubit with squeezed microwave and resonator nonlinearity
title_full Fast and high-fidelity dispersive readout of a spin qubit with squeezed microwave and resonator nonlinearity
title_fullStr Fast and high-fidelity dispersive readout of a spin qubit with squeezed microwave and resonator nonlinearity
title_full_unstemmed Fast and high-fidelity dispersive readout of a spin qubit with squeezed microwave and resonator nonlinearity
title_short Fast and high-fidelity dispersive readout of a spin qubit with squeezed microwave and resonator nonlinearity
title_sort fast and high fidelity dispersive readout of a spin qubit with squeezed microwave and resonator nonlinearity
url https://doi.org/10.1038/s41534-024-00924-8
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AT xuedonghu fastandhighfidelitydispersivereadoutofaspinqubitwithsqueezedmicrowaveandresonatornonlinearity