Union-Intersection Union-Find for Decoding Depolarizing Errors in Topological Codes

TL;DR

The paper presents the UIUF algorithm that enhances decoding of depolarizing errors in topological codes, combining iterative and Union-Find methods to improve error correction guarantees and performance.

Contribution

Introduces the UIUF algorithm that guarantees error correction up to half the code distance while outperforming standard UF and MWPM decoders.

Findings

UIUF reduces logical error rates by over an order of magnitude.

UIUF outperforms UF and MWPM decoders in simulations.

UIUF maintains linear-time complexity.

Abstract

In this paper, we introduce the Union-Intersection Union-Find (UIUF) algorithm for decoding depolarizing errors in topological codes, combining the strengths of iterative and standard Union-Find (UF) decoding. While iterative UF improves performance at moderate error rates, it lacks an error correction guarantee. To address this, we develop UIUF, which maintains the enhanced performance of iterative UF while ensuring error correction up to half the code distance. Through simulations under code capacity, phenomenological, and biased noise models, we show that UIUF significantly outperforms UF, reducing the logical error rate by over an order of magnitude (at around $10^{-5}$). Moreover, UIUF achieves lower logical error rates than the Minimum Weight Perfect Matching (MWPM) decoder on rotated surface codes under both the code capacity and phenomenological noise models, while preserving efficient linear-time complexity.