2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/56988The problem of the Bose-Einstein condensate preservation under thermofield and standard gauge-invariant perturbations is discussed. A new result on stability of the condensate under thermofield perturbations of a polynomial type is presented.pdf,13 pagesMathematical PhysicsStatistical MechanicsProbabilitytext