2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/51190We study gauge fixing in the generalized Gupta-Bleuler quantization. In this method physical states are defined to be simultaneous null eigenstates of a set of quantum invariants. We apply the method to a solvable model proposed by Friedberg, Lee, Pang and Ren and show that no Gribov-type copies appears by construction.High Energy Physics - Theorytext