Color code decoder with improved scaling for correcting circuit-level noise

Two-dimensional color codes are a promising candidate for fault-tolerant quantum computing, as they have high encoding rates, transversal implementation of logical Clifford gates, and resource-efficient magic state preparation schemes. However, decoding color codes presents a significant challenge d...

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Main Authors: Seok-Hyung Lee, Andrew Li, Stephen D. Bartlett
Format: Article
Language:English
Published: Verein zur Förderung des Open Access Publizierens in den Quantenwissenschaften 2025-01-01
Series:Quantum
Online Access:https://quantum-journal.org/papers/q-2025-01-27-1609/pdf/
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author Seok-Hyung Lee
Andrew Li
Stephen D. Bartlett
author_facet Seok-Hyung Lee
Andrew Li
Stephen D. Bartlett
author_sort Seok-Hyung Lee
collection DOAJ
description Two-dimensional color codes are a promising candidate for fault-tolerant quantum computing, as they have high encoding rates, transversal implementation of logical Clifford gates, and resource-efficient magic state preparation schemes. However, decoding color codes presents a significant challenge due to their structure, where elementary errors violate three checks instead of just two (a key feature in surface code decoding), and the complexity of extracting syndrome is greater. We introduce an efficient color-code decoder that tackles these issues by combining two matching decoders for each color, generalized to handle circuit-level noise by employing detector error models. We provide comprehensive analyses of the decoder, covering its threshold and sub-threshold scaling both for bit-flip noise with ideal measurements and for circuit-level noise. Our simulations reveal that this decoding strategy nearly reaches the best possible scaling of logical failure ($p_\mathrm{fail} \sim p^{d/2}$) for both noise models, where $p$ is the noise strength, in the regime of interest for fault-tolerant quantum computing. While its noise thresholds are comparable with other matching-based decoders for color codes ($8.2\%$ for bit-flip noise and $0.46\%$ for circuit-level noise), the scaling of logical failure rates below threshold significantly outperforms the best matching-based decoders.
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institution Kabale University
issn 2521-327X
language English
publishDate 2025-01-01
publisher Verein zur Förderung des Open Access Publizierens in den Quantenwissenschaften
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spelling doaj-art-7beca7f547f5407a83c25baf153c70c12025-01-27T13:34:10ZengVerein zur Förderung des Open Access Publizierens in den QuantenwissenschaftenQuantum2521-327X2025-01-019160910.22331/q-2025-01-27-160910.22331/q-2025-01-27-1609Color code decoder with improved scaling for correcting circuit-level noiseSeok-Hyung LeeAndrew LiStephen D. BartlettTwo-dimensional color codes are a promising candidate for fault-tolerant quantum computing, as they have high encoding rates, transversal implementation of logical Clifford gates, and resource-efficient magic state preparation schemes. However, decoding color codes presents a significant challenge due to their structure, where elementary errors violate three checks instead of just two (a key feature in surface code decoding), and the complexity of extracting syndrome is greater. We introduce an efficient color-code decoder that tackles these issues by combining two matching decoders for each color, generalized to handle circuit-level noise by employing detector error models. We provide comprehensive analyses of the decoder, covering its threshold and sub-threshold scaling both for bit-flip noise with ideal measurements and for circuit-level noise. Our simulations reveal that this decoding strategy nearly reaches the best possible scaling of logical failure ($p_\mathrm{fail} \sim p^{d/2}$) for both noise models, where $p$ is the noise strength, in the regime of interest for fault-tolerant quantum computing. While its noise thresholds are comparable with other matching-based decoders for color codes ($8.2\%$ for bit-flip noise and $0.46\%$ for circuit-level noise), the scaling of logical failure rates below threshold significantly outperforms the best matching-based decoders.https://quantum-journal.org/papers/q-2025-01-27-1609/pdf/
spellingShingle Seok-Hyung Lee
Andrew Li
Stephen D. Bartlett
Color code decoder with improved scaling for correcting circuit-level noise
Quantum
title Color code decoder with improved scaling for correcting circuit-level noise
title_full Color code decoder with improved scaling for correcting circuit-level noise
title_fullStr Color code decoder with improved scaling for correcting circuit-level noise
title_full_unstemmed Color code decoder with improved scaling for correcting circuit-level noise
title_short Color code decoder with improved scaling for correcting circuit-level noise
title_sort color code decoder with improved scaling for correcting circuit level noise
url https://quantum-journal.org/papers/q-2025-01-27-1609/pdf/
work_keys_str_mv AT seokhyunglee colorcodedecoderwithimprovedscalingforcorrectingcircuitlevelnoise
AT andrewli colorcodedecoderwithimprovedscalingforcorrectingcircuitlevelnoise
AT stephendbartlett colorcodedecoderwithimprovedscalingforcorrectingcircuitlevelnoise