A memory system comprising a qubit array configured to store therein one or more entangled qubit states encoded using a quantum stabilizer code. The memory system further comprises a quantum-state-refresh module configured to refresh an entangled qubit state in the qubit array when a degradation error is detected therein. The quantum-state-refresh module is further configured to detect the degradation error by performing a redundant measurement of a set of syndrome values corresponding to the quantum stabilizer code. The redundant measurement is based on an error-correction code defined using the generator matrix of the quantum stabilizer code and a corresponding supplemental parity-check matrix. In an example embodiment, each of the generator and supplemental parity-check matrices has a respective inclined-stripe form.