Completeness of the Bethe Ansatz solution of the open XXZ chain with nondiagonal boundary terms

TL;DR

This paper investigates the completeness of a Bethe Ansatz solution for the open XXZ spin chain with nondiagonal boundary conditions, providing evidence that it captures all eigenvalues and is useful for studying the model's ground state.

Contribution

The authors provide numerical evidence supporting the completeness of a recently proposed Bethe Ansatz solution for the open XXZ chain with nondiagonal boundaries.

Findings

The solution yields the complete set of eigenvalues for generic parameters.

It is practical for analyzing the ground state in the thermodynamic limit.

Numerical procedures confirm the solution's effectiveness.

Abstract

A Bethe Ansatz solution of the open spin-1/2 XXZ quantum spin chain with nondiagonal boundary terms has recently been proposed. Using a numerical procedure developed by McCoy et al., we find significant evidence that this solution can yield the complete set of eigenvalues for generic values of the bulk and boundary parameters satisfying one linear relation. Moreover, our results suggest that this solution is practical for investigating the ground state of this model in the thermodynamic limit.