2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/27780Non-Ohmic tunnel junctions are believed to occur in systems where the exciton and orthogonality catastrophe effects significantly modify tunneling rates. Here we present a simple non-perturbative treatment of the thermodynamic and transport properties of subOhmic and superOhmic tunnel junctions. The large-N approximation demonstrates the existence of a quantum phase transition in subOhmic but not superOhmic tunnel junctions. In addition, we find a pseudogap which vanishes continuously as the transition is approached.4 pages LaTeX. 1 .eps figureCondensed Mattertext