"New" boundary conditions in integrable lattice models

TL;DR

This paper introduces and analyzes soliton non-preserving boundary conditions in integrable quantum spin chains, providing new transfer matrix constructions, symmetry analysis, eigenvalues, and Bethe ansatz equations.

Contribution

It is the first study to incorporate soliton non-preserving boundary conditions into the spin chain framework, expanding the understanding of boundary effects in integrable models.

Findings

Constructed the transfer matrix for the new boundary conditions

Derived explicit eigenvalues of the transfer matrix

Formulated new Bethe ansatz equations for the model

Abstract

We consider the case of an integrable quantum spin chain with ``soliton non-preserving'' boundary conditions. This is the first time that such boundary conditions have been considered in the spin chain framework. We construct the transfer matrix of the model, we study its symmetry and we find explicit expressions for its eigenvalues. Moreover, we derive a new set of Bethe ansatz equations by means of the analytical Bethe ansatz method.