April 14, 2025
Quantum low-density parity-check (QLDPC) codes offer a path toward fault-tolerant quantum computing with reduced space overhead. However, simulating these codes at the circuit level presents significant challenges. To address this, we developed QUITS, a modular simulator designed for circuit-level studies of QLDPC codes. QUITS supports three prominent QLDPC code families: hypergraph-product (HGP), quasi-cyclic lifted-product (QLP), and balanced-product-cyclic (BPC) codes. For small HGP codes, it incorporates an optimized syndrome extraction circuit that reduces circuit depth and improves decoding performance. The simulator also features a sliding window decoding framework, allowing flexible integration and benchmarking of custom decoders. Through comprehensive evaluations, the tool reveals key trade-offs between decoding runtime and logical failure rates, offering a valuable resource for the advancement of quantum error correction.
Open-source repo: https://github.com/mkangquantum/quits
Manuscript: https://arxiv.org/abs/2504.02673
