Mitigating errors in logical qubits

Abstract Quantum error correcting codes can enable large quantum computations provided physical error rates are sufficiently low. We combine post-selection with surface code error correction through the use of exclusive decoders, which abort on decoding instances that are deemed too difficult. For t...

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Main Authors: Samuel C. Smith, Benjamin J. Brown, Stephen D. Bartlett
Format: Article
Language:English
Published: Nature Portfolio 2024-11-01
Series:Communications Physics
Online Access:https://doi.org/10.1038/s42005-024-01883-4
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author Samuel C. Smith
Benjamin J. Brown
Stephen D. Bartlett
author_facet Samuel C. Smith
Benjamin J. Brown
Stephen D. Bartlett
author_sort Samuel C. Smith
collection DOAJ
description Abstract Quantum error correcting codes can enable large quantum computations provided physical error rates are sufficiently low. We combine post-selection with surface code error correction through the use of exclusive decoders, which abort on decoding instances that are deemed too difficult. For the most discriminating of exclusive decoders, we demonstrate a threshold of 50% under depolarizing noise (or 32(1)% for the fault-tolerant case), and up to a quadratic improvement in logical failure rates below threshold. Furthermore, with a modest exclusion criterion, we identify a regime at low error rates where the exclusion rate decays with code distance, providing a pathway for scalable and time-efficient quantum computing with post-selection. Our exclusive decoder applied to magic state distillation yields a 75% reduction in the number of physical qubits, and a 60% reduction in the total spacetime volume, including accounting for repetitions. Other applications include error mitigation, and in concatenated schemes.
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spelling doaj-art-702a408c54b744f6a8ec02eef7eea34d2025-08-20T02:49:17ZengNature PortfolioCommunications Physics2399-36502024-11-017111010.1038/s42005-024-01883-4Mitigating errors in logical qubitsSamuel C. Smith0Benjamin J. Brown1Stephen D. Bartlett2Centre for Engineered Quantum Systems, School of Physics, University of SydneyIBM Quantum, T. J. Watson Research CenterCentre for Engineered Quantum Systems, School of Physics, University of SydneyAbstract Quantum error correcting codes can enable large quantum computations provided physical error rates are sufficiently low. We combine post-selection with surface code error correction through the use of exclusive decoders, which abort on decoding instances that are deemed too difficult. For the most discriminating of exclusive decoders, we demonstrate a threshold of 50% under depolarizing noise (or 32(1)% for the fault-tolerant case), and up to a quadratic improvement in logical failure rates below threshold. Furthermore, with a modest exclusion criterion, we identify a regime at low error rates where the exclusion rate decays with code distance, providing a pathway for scalable and time-efficient quantum computing with post-selection. Our exclusive decoder applied to magic state distillation yields a 75% reduction in the number of physical qubits, and a 60% reduction in the total spacetime volume, including accounting for repetitions. Other applications include error mitigation, and in concatenated schemes.https://doi.org/10.1038/s42005-024-01883-4
spellingShingle Samuel C. Smith
Benjamin J. Brown
Stephen D. Bartlett
Mitigating errors in logical qubits
Communications Physics
title Mitigating errors in logical qubits
title_full Mitigating errors in logical qubits
title_fullStr Mitigating errors in logical qubits
title_full_unstemmed Mitigating errors in logical qubits
title_short Mitigating errors in logical qubits
title_sort mitigating errors in logical qubits
url https://doi.org/10.1038/s42005-024-01883-4
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