Hidden Kondo Effect in a Correlated Electron Chain

TL;DR

This paper introduces a Bethe Ansatz approach to analyze a correlated electron chain with a magnetic impurity, revealing a hidden Kondo effect driven by forward scattering, and explains discrepancies in previous models regarding Kondo screening.

Contribution

It develops a general Bethe Ansatz formalism for arbitrary spin impurities and uncovers a hidden Kondo effect in an integrable electron chain model.

Findings

Exact solution shows a hidden Kondo effect due to forward scattering.

Operator reflection matrices may only emulate forward scattering, not full Kondo screening.

Certain impurity-electron couplings do not lead to complete Kondo screening.

Abstract

We develop a general Bethe Ansatz formalism for diagonalizing an integrable model of a magnetic impurity of arbitrary spin coupled ferro- or antiferromagnetically to a chain of interacting electrons. The method is applied to an open chain, with the exact solution revealing a ``hidden'' Kondo effect driven by forward electron scattering off the impurity. We argue that the so-called ``operator reflection matrices'' proposed in recent Bethe Ansatz studies of related models emulate only forward electron-impurity scattering which may explain the absence of complete Kondo screening for certain values of the impurity-electron coupling in these models.