2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/151688We show that the non-linear dc transport in a Luttinger liquid with interaction of finite range in the presence of an impurity is governed by a sum rule which causes the charging energy to vanish.5 pages, RevTeX, 1 figure, to be published in Europhysics LettersMesoscale and Nanoscale PhysicsStrongly Correlated Electronstext