Spin-reflection positivity of the Kondo lattice at half-filling

TL;DR

This paper investigates the spin-reflection positivity of the Kondo lattice model at half-filling, demonstrating ground state uniqueness across various exchange couplings and Coulomb interactions.

Contribution

It establishes the spin-reflection positivity and ground state uniqueness of the Kondo lattice model at half-filling for both antiferromagnetic and ferromagnetic couplings.

Findings

Ground state is unique for all positive Coulomb interactions U.

Spin-reflection positivity holds at half-filling for the Kondo lattice.

Results apply to both antiferromagnetic and ferromagnetic exchange couplings.

Abstract

We examine the spin-reflection positivity of the ground state of the Kondo lattice model at half-filling with the antiferromagnetic and ferromagnetic exchange couplings $J\ne0$. For every positive $U>0$, where U is the Coulomb interaction between the conduction electrons, we can show that the ground state is unique.