2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/212901We present relaxed criteria for quantum error correction which are useful when the specific dominant noise process is known. These criteria have no classical analogue. As an example, we provide a four-bit code which corrects for a single amplitude damping error. This code violates the usual Hamming bound calculated for a Pauli description of the error process, and does not fit into the GF(4) classification.7 pages, 2 figures, submitted to Phys. Rev. AQuantum Physicstext