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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

classification quant-ph
keywords blossomsparsedecoderquantumsyndromealgorithmcodescore
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abstract

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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Forward citations

Cited by 17 Pith papers

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score. OpenAlex reports about 36 citations worldwide. Full citation record

  1. 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 of 10

    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.

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

    quant-ph 2026-07 conditional novelty 7.0 of 10 partial

    In windowed quantum decoding, a wrong speculative boundary guess stays inside one window, and the predict-verify-recover loop removes the serial stall with negligible penalty.

  3. A Unitary Encoder for Surface Codes

    quant-ph 2025-06 conditional novelty 7.0 of 10

    A new non-local unitary encoder grows a rotated surface code from distance d to 2d-1 in four time steps, giving about 43% less depth than the previous best logarithmic-depth encoder.

  4. Improved belief propagation is sufficient for real-time decoding of quantum memory

    quant-ph 2025-06 conditional novelty 7.0 of 10

    Relay-BP, a message-passing decoder using disordered memory strengths and relay ensembling, matches or beats benchmark decoders for bivariate-bicycle and surface codes within a real-time iteration budget.

  5. Enhancing dissipative cat qubit protection by squeezing

    quant-ph 2025-02 conditional novelty 7.0 of 10

    A squeezed deformation of dissipative cat qubits, implemented with an extra pump, boosts bit-flip time 160-fold at fixed phase-flip time.

  6. The random coupled-plaquette gauge model and the surface code under circuit-level noise

    quant-ph 2024-12 conditional novelty 7.0 of 10

    A new 'random coupled-plaquette gauge model' couples X and Z syndrome lattices, yielding higher surface code thresholds when Y errors are properly accounted for.

  7. Transversal Logical Clifford gates on rotated surface codes with reconfigurable neutral atom arrays

    quant-ph 2024-12 conditional novelty 7.0 of 10

    The authors complete a transversal Clifford gate set on rotated surface codes by embedding a fold-transversal S gate inside a syndrome extraction round, with detector construction and numerical support.

  8. High-Performance and Scalable Fault-Tolerant Quantum Computation with Lattice Surgery on a 2.5D Architecture

    quant-ph 2024-11 conditional novelty 7.0 of 10

    A sparse second qubit layer (Bypass) shortens lattice surgery paths, reducing decoding bottlenecks and enabling a 2.5D FTQC architecture that is faster and uses fewer resources in simulation.

  9. Real-Time Dynamics in a (2+1)-D Gauge Theory: The Stringy Nature on a Superconducting Quantum Simulator

    quant-ph 2025-07 conditional novelty 6.0 of 10

    On a 144-qubit superconducting processor, the authors observe the real-time dynamics of confining electric strings in a (2+1)-D Z2 gauge theory, distinguishing longitudinal yo-yo modes from transverse bending and demo...

  10. Correcting a noisy quantum computer using a quantum computer

    quant-ph 2025-06 conditional novelty 6.0 of 10

    A variational quantum circuit, trained on syndrome data, decodes surface codes with accuracy close to minimum-weight perfect matching in classical simulation.

  11. Implementation of Magic State Injection within Heavy-Hexagon Architecture

    quant-ph 2024-12 conditional novelty 6.0 of 10

    On heavy-hexagon hardware with flag qubits, the ZXXZ orientation of the XZZX code with down-triangle qubit initialization gives the lowest logical error rate for magic state injection under biased noise.

  12. SymBreak: Mitigating Quantum Degeneracy Issues in QLDPC Code Decoders by Breaking Symmetry

    quant-ph 2024-12 conditional novelty 6.0 of 10

    SymBreak splits syndrome nodes during belief propagation, reporting 16x lower logical error rates than BP and 3.2x lower than BP+OSD for qLDPC codes, at near-BP runtime.

  13. Feasibility of Logical Bell State Generation in Memory Assisted Quantum Networks

    quant-ph 2024-12 conditional novelty 6.0 of 10

    Logical Bell-state protocols with d=3/5 surface and Bacon-Shor codes in ion traps need gate error rates around 10^-4 to 10^-5 to beat unencoded Bell states at 1 km, and the non-local protocol reaches about 33 Hz over ...

  14. 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 of 10

    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.

  15. Dynamics and rupture of doped Motility Induced Phase Peparation

    cond-mat.soft 2025-08 unverdicted novelty 5.0 of 10

    Adding passive particles to a phase-separated active suspension can produce a stable, self-sustained drift of the dense slab.

  16. Synchronization for Fault-Tolerant Quantum Computers

    quant-ph 2025-06 conditional novelty 5.0 of 10

    Active and Hybrid synchronization policies cut logical error rates by up to 2.4x and 3.4x compared to passive waiting, by distributing idle time across syndrome generation rounds.

  17. Controller-decoder system requirements derived by implementing Shor's algorithm with surface code

    quant-ph 2024-11 conditional novelty 5.0 of 10

    Running a non-Clifford surface-code circuit requires controller-decoder latency of tens of microseconds and parallel decoding tasks; a 1000-qubit, 0.1%-error processor could factor 21 with over 90% logical fidelity.

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