2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/202212The method of adiabatic invariants for time dependent Hamiltonians is applied to a massive scalar field in a de Sitter space-time. The scalar field ground state, its Fock space and coherent states are constructed and related to the particle states. Diverse quantities of physical interest are illustrated, such as particle creation and the way a classical probability distribution emerges for the system at late times.9 pages, Latex, no figuresGeneral Relativity and Quantum CosmologyHigh Energy Physics - Theorytext