We study the one-dimensional Holstein model of spinless fermions interacting with dispersion-less phonons by using a recently developed projector-based renormalization method (PRM). At half-filling the system shows a metal-insulator transition to a Peierls distorted state at a critical...

We present a non-perturbative study of an extended Falicov-Kimball model in one dimension. Working within the binary alloy interpretation, we include the spin of the itinerant electrons and a Hubbard interaction to model the inter-electron correlations. We derive an effective Ising model for the...

An analysis of Luttinger's theorem shows that – contrary to recent claims – it is not valid for a generic Mott insulator. For a two-orbital Hubbard model with two electrons per site the crossover from a non-magnetic correlated insulating phase (Mott or Kondo insulator) to a band insulator is...

We investigate polaron formation in a many-electron system in the presence of a local repulsion sufficiently strong to prevent local-bipolaron formation. Specifically, we consider a Hubbard-Holstein model of interacting electrons coupled to dispersionless phonons of frequency ω <Subscript>0</Subscript>. Numerically...</subscript>

In order to describe unbalanced ultracold fermionic quantum gases on optical lattices in a harmonic trap, we investigate an attractive (U 0) asymmetric (t<Subscript>↑</Subscript>≠t<Subscript>↓</Subscript>) Hubbard model with a Zeeman-like magnetic field. In view of the model's spatial inhomogeneity, we focus in this paper on the...</subscript></subscript>