Hierarchical quantum decoders

Fuente: arXiv
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Main Authors: Basak, Nirupam, Mohan, Ankith, Tanggara, Andrew, Haug, Tobias, Paul, Goutam, Bharti, Kishor
Format: Preprint
Published: 2026
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author Basak, Nirupam
Mohan, Ankith
Tanggara, Andrew
Haug, Tobias
Paul, Goutam
Bharti, Kishor
author_facet Basak, Nirupam
Mohan, Ankith
Tanggara, Andrew
Haug, Tobias
Paul, Goutam
Bharti, Kishor
contents Decoders are a critical component of fault-tolerant quantum computing. They must identify errors based on syndrome measurements to correct quantum states. While finding the optimal correction is NP-hard and thus extremely difficult, approximate decoders with faster runtime often rely on uncontrolled heuristics. In this work, we propose a family of hierarchical quantum decoders with a tunable trade-off between speed and accuracy while retaining guarantees of optimality. We use the Lasserre Sum-of-Squares (SOS) hierarchy from optimization theory to relax the decoding problem. This approach creates a sequence of Semidefinite Programs (SDPs). Lower levels of the hierarchy are faster but approximate, while higher levels are slower but more accurate. We demonstrate that even low levels of this hierarchy significantly outperform standard Linear Programming relaxations. Our results on rotated surface codes and honeycomb color codes show that the SOS decoder approaches the performance of exact decoding. We find that Levels 2 and 3 of our hierarchy perform nearly as well as the exact solver. We analyze the convergence using rank-loop criteria and compare the method against other relaxation schemes. This work bridges the gap between fast heuristics and rigorous optimal decoding.
format Preprint
id arxiv_https___arxiv_org_abs_2601_21715
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Hierarchical quantum decoders
Basak, Nirupam
Mohan, Ankith
Tanggara, Andrew
Haug, Tobias
Paul, Goutam
Bharti, Kishor
Quantum Physics
Decoders are a critical component of fault-tolerant quantum computing. They must identify errors based on syndrome measurements to correct quantum states. While finding the optimal correction is NP-hard and thus extremely difficult, approximate decoders with faster runtime often rely on uncontrolled heuristics. In this work, we propose a family of hierarchical quantum decoders with a tunable trade-off between speed and accuracy while retaining guarantees of optimality. We use the Lasserre Sum-of-Squares (SOS) hierarchy from optimization theory to relax the decoding problem. This approach creates a sequence of Semidefinite Programs (SDPs). Lower levels of the hierarchy are faster but approximate, while higher levels are slower but more accurate. We demonstrate that even low levels of this hierarchy significantly outperform standard Linear Programming relaxations. Our results on rotated surface codes and honeycomb color codes show that the SOS decoder approaches the performance of exact decoding. We find that Levels 2 and 3 of our hierarchy perform nearly as well as the exact solver. We analyze the convergence using rank-loop criteria and compare the method against other relaxation schemes. This work bridges the gap between fast heuristics and rigorous optimal decoding.
title Hierarchical quantum decoders
topic Quantum Physics
url https://arxiv.org/abs/2601.21715