2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/230443The old problem exists for a driven (time-dependent) quantum oscillator: to differ the true vacuum state from the squeezed one. We suggest finding the true vacuum state by minimization of the functional containing the difference of the potential and kinetic energies of oscillator. Analytical and numerical examples confirming this offer are considered.9 pagesQuantum PhysicsGeneral Relativity and Quantum CosmologyHigh Energy Physics - TheoryComputational Physicstext