Sparse-Blossom Decoding in $o(1)$ Time
A preprint posted to arXiv presents a sparse blossom decoder for quantum error correction that is claimed to run in o(1) time. The approach builds on minimum-weight perfect matching, which gives rigorous error-suppression guarantees, and extends earlier sparse blossom techniques that were practical only at modest problem sizes.
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What this could mean
- 0–2 yearsPlausible
This could let surface-code experiments from Google or IBM run MWPM decoding in real time on larger code patches within two years, removing decode latency as a limit on logical clock speed.
Existing sparse blossom decoders already approach real-time performance at modest distances; an o(1)-time variant would decouple matching complexity from code size. Integration with control electronics and validation under circuit-level noise remain preconditions.
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