2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/95877We prove an adiabatic theorem for the evolution of spectral data under a weak additive perturbation in the context of a system without an intrinsic time scale. For continuous functions of the unperturbed Hamiltonian the convergence is in norm while for a larger class functions, including the spectral projections associated to embedded eigenvalues, the convergence is in the strong operator topology.15 pages, no figuresMathematical PhysicsMesoscale and Nanoscale PhysicsQuantum Physicstext