2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/169984The subject of this work is to apply the modified Feynman disentangling approach to a problem of transitions in a non-quadratic quantum-mechanical system: a singular oscillator with a time-dependent frequency.4 pages, LaTeX2e. To be published in the Proceedings of the XIII International Conference "Selected problems of modern theoretical physics", Dubna, Russia, June 2008Quantum PhysicsHigh Energy Physics - PhenomenologyHigh Energy Physics - Theorytext