2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/196116It is shown by an explicit calculation that the excitations about the self-accelerating cosmological solution of the Dvali--Gabadaze--Porrati model contain a ghost mode. This raises serious doubts about viability of this solution. Our analysis reveals the similarity between the quadratic theory for the perturbations around the self-accelerating Universe and an Abelian gauge model with two Stueckelberg fields.Revtex, 9 pages, no figuresHigh Energy Physics - TheoryAstrophysicsGeneral Relativity and Quantum Cosmologytext