Boundary energy of the open XXZ chain from new exact solutions

TL;DR

This paper uses new Bethe Ansatz solutions to compute the boundary energy of the open XXZ quantum spin chain at roots of unity, providing insights into surface energy in the thermodynamic limit.

Contribution

It introduces a novel application of recent Bethe Ansatz solutions to calculate boundary energy in an integrable quantum spin chain.

Findings

Boundary energy computed at roots of unity

Explicit formulas for surface energy derived

Enhanced understanding of boundary effects in XXZ chain

Abstract

Bethe Ansatz solutions of the open spin-1/2 integrable XXZ quantum spin chain at roots of unity with nondiagonal boundary terms containing two free boundary parameters have recently been proposed. We use these solutions to compute the boundary energy (surface energy) in the thermodynamic limit.