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A scalable and real-time neural decoder for topological quantum codes

Published: December 8, 2025 | arXiv ID: 2512.07737v1

By: Andrew W. Senior , Thomas Edlich , Francisco J. H. Heras and more

Potential Business Impact:

Makes quantum computers work correctly and faster.

Business Areas:
Quantum Computing Science and Engineering

Fault-tolerant quantum computing will require error rates far below those achievable with physical qubits. Quantum error correction (QEC) bridges this gap, but depends on decoders being simultaneously fast, accurate, and scalable. This combination of requirements has not yet been met by a machine-learning decoder, nor by any decoder for promising resource-efficient codes such as the colour code. Here we introduce AlphaQubit 2, a neural-network decoder that achieves near-optimal logical error rates for both surface and colour codes at large scales under realistic noise. For the colour code, it is orders of magnitude faster than other high-accuracy decoders. For the surface code, we demonstrate real-time decoding faster than 1 microsecond per cycle up to distance 11 on current commercial accelerators with better accuracy than leading real-time decoders. These results support the practical application of a wider class of promising QEC codes, and establish a credible path towards high-accuracy, real-time neural decoding at the scales required for fault-tolerant quantum computation.

Page Count
42 pages

Category
Physics:
Quantum Physics