一句话：提出实时自适应预解码器 Promatch，用局部性感知贪心预匹配降低综合征汉明重量，使实时 MWPM 首次可解码距离 11 与 13 的 surface code。
容错量子计算依赖量子纠错，解码器必须把测得的校验位实时（超导机器上 1μs 内）翻译为错误类型与位置。最小权重完美匹配（MWPM）对 surface code 精度高，但已有实时实现（RT-MWPM）仅支持到距离 9：再往上，综合征中被翻转校验位的数量（综合征汉明重量）超出解码器能力。本文提出 Promatch——一个实时自适应预解码器，用局部性感知的贪心方法对简单与复杂错误模式做预匹配，把高汉明重量综合征转换为低汉明重量综合征，再交由 RT-MWPM 精确解码。设计需同时保证预匹配的准确率（预解码的错误会直接抬高整体逻辑错误率 LER）与覆盖率（须在时间约束下把重量压到主解码器可处理的范围）。Promatch 是首个可实时解码距离 11 和 13 的框架，距离 13 时 LER 为 2.6×10⁻¹⁴；与 Astrea-G 并发运行后，距离 13 的 LER 达到与 MWPM 相当的 3.4×10⁻¹⁵，成为首个可实时精确解码至距离 13 的解码器。
Fault-tolerant quantum computing relies on Quantum Error Correction (QEC), which encodes logical qubits into data and parity qubits. Error decoding is the process of translating the measured parity bits into types and locations of errors. To prevent a backlog of errors, error decoding must be performed in real-time (i.e., within 1μs on superconducting machines). Minimum Weight Perfect Matching (MWPM) is an accurate decoding algorithm for surface code, and recent research has demonstrated real-time implementations of MWPM (RT-MWPM) for a distance of up to 9. Unfortunately, beyond d=9, the number of flipped parity bits in the syndrome, referred to as the Hamming weight of the syndrome, exceeds the capabilities of existing RT-MWPM decoders. In this work, our goal is to enable larger distance RT-MWPM decoders by using adaptive predecoding that converts high Hamming weight syndromes into low Hamming weight syndromes, which are accurately decoded by the RT-MWPM decoder. An effective predecoder must balance both accuracy (as any erroneous decoding by the predecoder contributes to the overall Logical Error Rate, termed as LER) and coverage (as the predecoder must ensure that the hamming weight of the syndrome is within the capability of the final decoder). In this paper, we propose Promatch, a real-time adaptive predecoder that predecodes both simple and complex patterns using a locality-aware, greedy approach. Our approach ensures two crucial factors: 1) high accuracy in prematching flipped bits, ensuring that the decoding accuracy is not hampered by the predecoder, and 2) enough coverage adjusted based on the main decoder's capability given the time constraints. Promatch represents the first real-time decoding framework capable of decoding surface codes of distances 11 and 13, achieving an LER of 2.6 × 10-14 for distance 13. Moreover, we demonstrate that running Promatch concurrently with the recently proposed Astrea-G achieves LER equivalent to MWPM LER, 3.4 × 10-15, for distance 13, representing the first real-time accurate decoder for up-to a distance of 13.
DOI 原文 · arXiv · PDF（开放获取） · DBLP
@inproceedings{AlavisamaniVA0Q24,
title = {Promatch: Extending the Reach of Real-Time Quantum Error Correction with Adaptive Predecoding},
author = {Narges Alavisamani and Suhas Vittal and Ramin Ayanzadeh and Poulami Das and Moinuddin Qureshi},
booktitle = {ASPLOS},
year = {2024},
doi = {10.1145/3620666.3651339}
}