Edge-Based Anisotropic Decoding for Generalized Bicycle Codes

Fuente: arXiv
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Main Authors: Chytas, Dimitris, Fessatidis, Paul N., Bash, Boulat A., Vasić, Bane
Format: Preprint
Published: 2026
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author Chytas, Dimitris
Fessatidis, Paul N.
Bash, Boulat A.
Vasić, Bane
author_facet Chytas, Dimitris
Fessatidis, Paul N.
Bash, Boulat A.
Vasić, Bane
contents Quantum low-density parity-check (QLDPC) codes provide non vanishing rates, distance scaling with the blocklength of the code, and facilitate fast iterative decoding because of their sparsity. However, in practice iterative decoding fails to exploit the distance of the code, because it cannot resolve the symmetries imposed by degeneracy. In this work, we provide a graph theoretic characterization of degeneracy for the family of generalized bicycle (GB) codes. This viewpoint shows that harmful degenerate error patterns persist whenever they remain related by automorphisms preserved by the decoder. Motivated by symmetry breaking via graph coloring, we compare three coloring approaches: no coloring, block-coloring, and edge-coloring. For GB codes, we show that edge-coloring can eliminate all automorphisms in low-weight stabilizer-induced subgraphs. We practically realize the coloring schemes as isotropic, block- anisotropic and edge-anisotropic min-sum (MS) decoding. Experimental results show that edge anisotropic min-sum decoding obtains improved performance over isotropic and block anisotropic decoding for several GB codes in a small number of iterations.
format Preprint
id arxiv_https___arxiv_org_abs_2605_03218
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Edge-Based Anisotropic Decoding for Generalized Bicycle Codes
Chytas, Dimitris
Fessatidis, Paul N.
Bash, Boulat A.
Vasić, Bane
Quantum Physics
Information Theory
Quantum low-density parity-check (QLDPC) codes provide non vanishing rates, distance scaling with the blocklength of the code, and facilitate fast iterative decoding because of their sparsity. However, in practice iterative decoding fails to exploit the distance of the code, because it cannot resolve the symmetries imposed by degeneracy. In this work, we provide a graph theoretic characterization of degeneracy for the family of generalized bicycle (GB) codes. This viewpoint shows that harmful degenerate error patterns persist whenever they remain related by automorphisms preserved by the decoder. Motivated by symmetry breaking via graph coloring, we compare three coloring approaches: no coloring, block-coloring, and edge-coloring. For GB codes, we show that edge-coloring can eliminate all automorphisms in low-weight stabilizer-induced subgraphs. We practically realize the coloring schemes as isotropic, block- anisotropic and edge-anisotropic min-sum (MS) decoding. Experimental results show that edge anisotropic min-sum decoding obtains improved performance over isotropic and block anisotropic decoding for several GB codes in a small number of iterations.
title Edge-Based Anisotropic Decoding for Generalized Bicycle Codes
topic Quantum Physics
Information Theory
url https://arxiv.org/abs/2605.03218