The thermodynamic properties of the XXZ spin chain with integrable open boundary conditions at the gaped region (i.e., the anisotropic parameter η being a real number) are investigated.It is shown that the contribution of the inhomogeneous term in the T−Q relation of the ground state and elementary excited state can be neglected when the size of the system N tends to infinity. The surface energy and elementary excitations induced by the unparallel boundary magnetic fields are obtained.
@article{arxiv.1901.01514,
title = {Surface energy and elementary excitations of the XXZ spin chain with arbitrary boundary fields},
author = {Pei Sun and Zhi-Rong Xin and Yi Qiao and Kun Hao and Like Cao and Junpeng Cao and Tao Yang and Wen-Li Yang},
journal= {arXiv preprint arXiv:1901.01514},
year = {2019}
}