Ground-state properties of multicomponent Falicov-Kimball-like models I

TL;DR

This paper rigorously demonstrates that coupling a multicomponent classical lattice gas to a free-fermion gas in a Falicov-Kimball-like manner induces order in the classical subsystem, removing its macroscopic degeneracy.

Contribution

It introduces a model coupling multicomponent classical and quantum gases and proves that this coupling induces order, resolving degeneracy in the classical subsystem.

Findings

Coupling removes macroscopic degeneracy in the classical subsystem.

Order is induced in the classical lattice gas through quantum coupling.

The model extends understanding of classical-quantum interactions in lattice systems.

Abstract

We consider a classical lattice gas that consists of more than one "species" of particles (like a spin-3/2 Ising model or the atomic limit of the extended Hubbard model), whose ground-state phase diagram is macroscopically degenerate. This gas is coupled component-wise and in the Falicov-Kimball-like manner to a multicomponent free-fermion gas. We show rigorously that a component-wise coupling of the classical subsystem to the quantum one orders the classical subsystem so that the macroscopic degeneracy is removed.