A Hubbard model with integrable impurity

TL;DR

This paper develops an integrable Hubbard model with an impurity that has spin and charge degrees of freedom, deriving Bethe ansatz equations and analyzing thermodynamical properties using TBA and QTM methods.

Contribution

It introduces a new integrable Hubbard model with an impurity and provides a comprehensive thermodynamic analysis using Bethe ansatz techniques.

Findings

Impurity contribution to thermodynamical potential expressed by integral formulas

Derivation of Bethe ansatz equations for the impurity model

Application of TBA and QTM methods to analyze thermodynamics

Abstract

We construct an integrable Hubbard model with impurity site containing spin and charge degrees of freedom. The Bethe ansatz equations for the Hamiltonian are derived and two alternative sets of equations for the thermodynamical properties. For this study, the thermodynamical Bethe ansatz and the quantum transfer matrix approach are used. The latter approach allows for a consistent treatment by use of a finite set of non-linear integral equations. In both cases, TBA and QTM, the contribution of the impurity to the thermodynamical potential is given by integral expressions.