2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/223360We quantize a real massive Klein-Gordon field in curved spacetimes within the general boundary formulation. The vacuum wave function is given by a Gaussian in the Schrödinger representation and we study the general structure of the operator appearing in the Gaussian. We show that it obeys a Riccati equation and we provide the general solution.10 pages, LaTeX + revtex4High Energy Physics - Theorytext