PME SPECIAL QUANTUM SEMINAR SERIES - Good Quantum LDPC Codes and How to Decode Them

The last few years have seen rapid progress in the development of quantum low-density parity-check (LDPC) codes, which are defined by constant-weight check operators. In particular, a series of pivotal works culminated in the discovery of asymptotically good codes--those with essentially optimal rate and distance scalings. These codes allow for the possibility of fault-tolerant quantum computation with very low overhead. However, for a code to be used in practice, it is necessary to efficiently identify errors from measurement outcomes to get back into the codespace. In this talk, I will present a linear-time decoder for a family of asymptotically good codes called quantum Tanner codes. Furthermore, I will show that quantum Tanner codes support single-shot decoding, which means that one measurement round suffices to perform reliable quantum error correction even in the presence of measurement errors. These results can be seen as a step toward making quantum LDPC codes more practical.

Host: Liang Jiang | liangjiang@uchicago.edu