2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/144526We investigate serial double quantum dot systems with on-site and inter-site interaction by means of Schönhammer-Gunnarsson projection-operator method. The ground state is established by the competition between extended Kondo phases and localized singlet phases in spi$ degrees of freedom. We present and discuss different phases, as discerned by characteristic correlation functions. We discuss also how different phases would be seen in linear transport measurements.5 pages, 2 figures, presented on "XI Training Course in the Physics of Strongly Correlated Systems", Vietri sul Mare, Salerno, ItalyMesoscale and Nanoscale PhysicsStrongly Correlated Electronstext