2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/88968A conceptually simple method for derivation of lower bounds on the error exponent of specific families of block codes used on classical-quantum channels with arbitrary signal states over a finite Hilbert space is presented. It is shown that families of binary block codes with appropriately rescaled binomial multiplicity enumerators used on binary classical-quantum channels and decoded by the suboptimal decision rule introduced by Holevo attain the expurgated and cutoff rate lower bounds on the error exponent.Quantum Physicstext