2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/131545In this paper, we present an invariant perturbation theory of the adiabatic process based on the concepts of U(1)-invariant adiabatic orbit and U(1)-invariant adiabatic expansion. As its application, we propose and discuss new adiabatic approximation conditions.4 pages, no figuresQuantum Physicstext