2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/89988We introduce a general, simple and effective method of evaluating the zero point energy of a quantum field under the influence of arbitrary boundary conditions imposed on the field on flat surfaces perpendicular to a chosen spatial direction. As an example we apply the method to the Casimir effect associated with a massive fermion field on which MIT bag model type of boundary conditions are imposed.7 pages, no figures, Latex fileQuantum PhysicsHigh Energy Physics - Theorytext