2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/90157The geometrical phase of a time-dependent singular oscillator is obtained in the framework of Gaussian wave packet. It is shown by a simple geometrical approach that the geometrical phase is connected to the classical nonadiabatic Hannay angle of the generalized harmonic oscillator.11 pages, no figures. Submited to Phys. Rev. LettQuantum Physicstext