Скачать или смотреть Quantum Spain Seminar: Advances in low-overhead quantum error correction

Speaker: Josu Etxezarreta

Abstract: The extremely fragile nature of quantum information implies that quantum error correction (QEC) techniques are going to be necessary to obtain the full benefits that quantum computing offers theoretically. While QEC has been experimentally proven to be effective, it requires significant overheads that should be alleviated. In this talk, I will discuss our recent advances towards low-overhead quantum error correction. First, I will discuss how to leverage biased noise in technologies that do not allow for a bias-preserving CNOT gate (arXiv:2505.17718). Our numerical results imply that up to a 75% qubit reduction can be achieved using the XZZX surface code. Second, quantum low-density parity-check (qLDPC) codes have been recently proposed as viable ways to reduce qubit footprints significantly, but they lack an efficient decoding algorithm. I will introduce our proposal, named Belief Propagation Ordered Tanner Forest (BP+OTF) decoding (arXiv:2409.01440). Numerical simulations show that the BP+OTF decoder achieves similar logical error suppression compared to state-of-the-art inversion-based and matching decoders for bivariate bicycle and surface codes, respectively, while maintaining almost-linear runtime complexity across all stages.