2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/93460The idea of equivalence of the free electromagnetic phase and quantum-mechanical one is investigated in an attempt to seek modifications of Schrödinger's equation that could realize it. It is assumed that physically valid realizations are compatibile with the U(1)-gauge and Galilean invariance. It is shown that such extensions of the Schrödinger equation do not exist, which also means that despite their apparent similarity the quantum-mechanical phase is essentially different from the electromagnetic one.Latex, 5 pages, the list of references updatedQuantum Physicstext