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Sparse Blossom: correcting a million errors per core second with minimum-weight matching

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arxiv 2303.15933 v2 pith:ZNG24YP3 submitted 2023-03-28 quant-ph

Sparse Blossom: correcting a million errors per core second with minimum-weight matching

classification quant-ph
keywords blossomsparsedecoderquantumsyndromealgorithmcodescore
verification ladder T0 review T1 audit T2 compute T3 formal T4 reserved
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In this work, we introduce a fast implementation of the minimum-weight perfect matching (MWPM) decoder, the most widely used decoder for several important families of quantum error correcting codes, including surface codes. Our algorithm, which we call sparse blossom, is a variant of the blossom algorithm which directly solves the decoding problem relevant to quantum error correction. Sparse blossom avoids the need for all-to-all Dijkstra searches, common amongst MWPM decoder implementations. For 0.1% circuit-level depolarising noise, sparse blossom processes syndrome data in both $X$ and $Z$ bases of distance-17 surface code circuits in less than one microsecond per round of syndrome extraction on a single core, which matches the rate at which syndrome data is generated by superconducting quantum computers. Our implementation is open-source, and has been released in version 2 of the PyMatching library.

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Cited by 16 Pith papers

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score.

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    quant-ph 2026-02 unverdicted novelty 8.0

    Union-find decoder for surface code achieves finite threshold under circuit-level stochastic errors with quasi-polylog parallel runtime bound.

  2. Physics-Informed Graph-Neural Decoding of the Surface Code: the Logical Signal as an Exact Topological Pairing

    quant-ph 2026-07 conditional novelty 7.0

    The logical-error signal in a surface-code decoder is an exact relative-cohomology pairing of the syndrome with a boundary-fixed harmonic coordinate, evaluated as the current difference between two boundary sinks.

  3. The verifier side of speculative window decoding: a predictability bracket, a machine-checked blast-radius bound, and a decoder-agnostic recover loop

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  4. The dynamic 4.8.8 Floquet code

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    A dynamic measurement circuit for the 4.8.8 Floquet code preserves full spatial distance and reaches per-round thresholds up to 0.512% under circuit-level depolarizing noise, outperforming standard ancilla-based circuits.

  5. Simplified circuit-level decoding using Knill error correction

    quant-ph 2026-03 accept novelty 7.0

    Knill error correction reduces circuit-level decoding for quantum LDPC codes to the simpler code-capacity decoder while remaining fault-tolerant under locally decaying noise.

  6. Magic state cultivation: growing T states as cheap as CNOT gates

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    Magic state cultivation prepares high-fidelity T states with an order of magnitude fewer qubit-rounds than prior distillation methods by gradually growing them within a surface code under depolarizing noise.

  7. LUCI on IBM Hardware: Error Suppression with Almost Half Syndrome Density

    quant-ph 2026-07 conditional novelty 6.0

    Hardware experiment on IBM devices shows reset-free LUCI achieves logical X and Z error suppression ratios of 1.75(10) and 1.93(12), competitive with surface code despite halved syndrome density.

  8. Approximating optimal decoding of quantum LDPC codes with narrow frontiers

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  9. Real-time Surface-Code Error Correction Using an FPGA-based Neural-Network Decoder

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  10. Magic State Injection on IBM Quantum Processors Above the Distillation Threshold

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  11. Taming Rydberg Decay with Measurement-based Quantum Computation

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    MBQC on topological cluster states locates Rydberg decay errors via final detection only, achieving 3.65% threshold per CZ gate and d_e ≈ d with lower overhead than erasure conversion.

  12. Latency-Constrained Hardware-Aware Quantum Error Correction Co-Design with Adaptive Confidence-Gated Neural Decoding for the Rotated Surface Code

    quant-ph 2026-07 conditional novelty 5.0

    A confidence-gated cascade decoder routes 3-6% of surface-code syndromes to exact MWPM refinement, improving logical accuracy from 99.21% to 99.81% at d=7 while keeping the fast neural path as the dominant cost center.

  13. Latency-Constrained Hardware-Aware Quantum Error Correction Co-Design with Adaptive Confidence-Gated Neural Decoding for the Rotated Surface Code

    quant-ph 2026-07 conditional novelty 5.0

    Confidence-gated neural decoding escalates only ~3–6% of rotated-surface-code syndromes to MWPM and raises end-to-end accuracy from 99.21% to 99.81% at d=7 under circuit-level depolarising noise.

  14. Quantum Network Routing based on Surface Code Error Correction

    quant-ph 2026-06 unverdicted novelty 5.0

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  15. Soft information decoding with superconducting qubits

    quant-ph 2024-11 unverdicted novelty 5.0

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  16. Managing Classical Processing Requirements for Quantum Error Correction

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