  We propose a post-processing method for message-passing (MP) decoding of CSS
quantum LDPC codes, called stabilizer-inactivation (SI). It relies on
inactivating a set of qubits, supporting a check in the dual code, and then
running the MP decoding again. This allows MP decoding to converge outside the
inactivated set of qubits, while the error on these is determined by solving a
small, constant size, linear system. Compared to the state of the art
post-processing method based on ordered statistics decoding (OSD), we show
through numerical simulations that MP-SI outperforms MP-OSD for different
quantum LDPC code constructions, different MP decoding algorithms, and
different MP scheduling strategies, while having a significantly reduced
complexity.
