Pathfinder-BP: A Low-Latency Recursive Decoder for Topological Codes

Abstract:We propose Pathfinder-BP, a recursive decoder for topological quantum codes that combines belief propagation with controlled bit-flipping. An initial BP pass identifies and permanently fixes high-confidence errors. Upon convergence failure, the decoder recursively explores alternative error patterns by tentatively flipping low-confidence variables. On surface codes, Pathfinder-BP achieves a noise threshold and logical error rate comparable to minimum-weight perfect matching (MWPM). A crucial advantage of Pathfinder-BP is its highly parallelizable structure, which yields a worst-case decoding latency quasi-linear in the code distance, making it a suitable candidate for low-latency hardware implementation.

Quantum Physics (quant-ph); Information Theory (cs.IT)

arXiv:2610.16375 [quant-ph]

(or arXiv:2610.16375v1 [quant-ph] for this version)

https://doi.org/10.48550/arXiv.2610.16375 Focus to learn more arXiv-issued DOI via DataCite (pending registration)

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