2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/142696In this paper, we study the one-level Friedrichs model with using the quantum time super-operator that predicts the excited state decay inside the continuum. Its survival probability in long time limit is an algebraically decreasing function and an exponentially decreasing multiplied by the oscillating functions.This paper will be published in the proceeding of XXV Workshop on Geometric Methods in Physics in the Journal of Geometry and Symmetry in PhysicsQuantum Physicstext