2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/170844For many quantum models an apparent non-Hermiticity of observables corresponds to their hidden Hermiticity in another, physical Hilbert space. For these models we show that the existence of observables which are manifestly time-dependent may require the use of a manifestly time-dependent representation of the physical Hilbert space of states.14 ppQuantum Physicstext