2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/159381To investigate ultracold fermionic atoms of three internal states (colors) in an optical lattice, subject to strong attractive interaction, we study the attractive three-color Hubbard model in infinite dimensions by using a variational approach. We find a quantum phase transition between a weak-coupling superconducting phase and a strong-coupling trionic phase where groups of three atoms are bound to a composite fermion. We show how the Gutzwiller variational theory can be reformulated in terms of an effective field theory with three-body interactions and how this effective field theory can be solved exactly in infinite dimensions by using the methods of dynamical mean field theory.14 PRB pages, 8 figuresSuperconductivityStrongly Correlated ElectronsTrionic phase of ultracold fermions in an optical lattice: A variational studytext