Falicov-Kimball Models: A Partial Review of the Ground States Problem

In this review we present a biased review of the ground state properties of the Falicov-Kimball models in 1,2 and infinite dimensions, considering either fermions or hard-core bosons. In particular we want to show the very rich structure that these models exhibit and to point out the analogies and differences associated with the statistic of the quantum particles and the nature of the lattice (bipartite or not). The flux phase problem is also discussed.