Interaction-resistant metals in multicomponent Fermi systems

We analyze two different fermionic systems that defy Mott localization showing a metallic ground state at integer filling and very large Coulomb repulsion. The first is a multiorbital Hubbard model with a Hund's coupling, where this physics has been widely studied and the new metallic state is called a Hund's metal, and the second is a SU($3$) Hubbard model with a patterned single-particle potential designed to retain important features of the multiorbital Hubbard model in a set-up which can be implemented with SU($N$) ultracold atoms. With simple analytical arguments, and by means of the exact numerical diagonalization of the Hamiltonians for a minimal three-site system, we identify a common scenario where the interaction-resistant metal emerges as a compromise between different terms, each leading to a different insulating state.