Although BP decoders are efficient and provide significant
performance for classical low-density parity-check (LDPC)
codes, they will suffer a degradation in performance for quantum
LDPC (QLDPC) codes due to the limitations in the quantum
field. In this paper, we propose a posterior adjustment of
either a single qubit or multiple qubits within binary belief
propagation (BP). The adjustment process changes the posterior
likelihood ratio for one or multiple qubits according to the
designed criterion. Simulations show the performance of both
single and multi-qubit adjustment is able to outperform the
conventional binary BP decoder and also outperform the BP
decoder concatenated with the zero-order ordered-statistics
decoding (BP+OSD-0). Moreover, with lower complexity,
the performance when using our proposed decoder on the
considered QLDPC codes can be close to high-order OSD.