%0 Journal Article
%T Surface free energy of the open XXZ spin-1/2 chain
%A K. K. Kozlowski
%A B. Pozsgay
%J Physics
%D 2012
%I arXiv
%R 10.1088/1742-5468/2012/05/P05021
%X We study the boundary free energy of the XXZ spin-$\tf{1}{2}$ chain subject to diagonal boundary fields. We first show that the representation for its finite Trotter number approximant obtained by Bortz, Frahm and G\"{o}hmann is related to the partition function of the six-vertex model with reflecting ends. Building on the Tsuchiya determinant representation for the latter quantity we are able to take the infinite Trotter number limit. This yields a representation for the surface free energy which involves the solution of the non-linear integral equation that governs the thermodynamics of the XXZ spin-1/2 chain subject to periodic boundary conditions. We show that this integral representation allows one to extract the low-$T$ asymptotic behavior of the boundary magnetization at finite external magnetic field on the one hand and numerically plot this function on the other hand.
%U http://arxiv.org/abs/1201.5884v3