{"ID":2883699,"CreatedAt":"2026-06-01T04:54:23.091178241Z","UpdatedAt":"2026-06-01T04:54:23.091178241Z","DeletedAt":null,"paper_url":"https://arxiv.org/abs/2508.07879","arxiv_id":"2508.07879","title":"GPU-Accelerated Syndrome Decoding for Quantum LDPC Codes below the 63 $μ$s Latency Threshold","abstract":"This paper presents a GPU-accelerated decoder for quantum low-density parity-check (QLDPC) codes that achieves sub-$63$ $μ$s latency, below the surface code decoder's real-time threshold demonstrated on Google's Willow quantum processor. While surface codes have demonstrated below-threshold performance, the encoding rates approach zero as code distances increase, posing challenges for scalability. Recently proposed QLDPC codes, such as those by Panteleev and Kalachev, offer constant-rate encoding and asymptotic goodness but introduce higher decoding complexity. To address such limitation, this work presents a parallelized belief propagation decoder leveraging syndrome information on commodity GPU hardware. Parallelism was exploited to maximize performance within the limits of target latency, allowing decoding latencies under $50$ $μ$s for [[$784$, $24$, $24$]] codes and as low as $23.3$ $μ$s for smaller codes, meeting the tight timing constraints of superconducting qubit cycles. These results show that real-time, scalable decoding of asymptotically good quantum codes is achievable using widely available commodity hardware, advancing the feasibility of fault-tolerant quantum computation beyond surface codes.","short_abstract":"This paper presents a GPU-accelerated decoder for quantum low-density parity-check (QLDPC) codes that achieves sub-$63$ $μ$s latency, below the surface code decoder's real-time threshold demonstrated on Google's Willow quantum processor. While surface codes have demonstrated below-threshold performance, the encoding ra...","url_abs":"https://arxiv.org/abs/2508.07879","url_pdf":"https://arxiv.org/pdf/2508.07879v1","authors":"[\"Oscar Ferraz\",\"Bruno Coutinho\",\"Gabriel Falcao\",\"Marco Gomes\",\"Francisco A. Monteiro\",\"Vitor Silva\"]","published":"2025-08-11T11:53:00Z","proceeding":"quant-ph","tasks":"[\"quant-ph\",\"cs.DC\"]","methods":"[]","has_code":false}