2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/25737In the first part we calculate the boundary susceptibility $χ_B$ in the open $XXZ$-chain at zero temperature and arbitrary magnetic field $h$ by Bethe ansatz. We present analytical results for the leading terms when $|h|\ll α$, where $α$ is a known scale, and a numerical solution for the entire range of fields. In the second part we calculate susceptibility profiles near the boundary at finite temperature $T$ numerically by using the density-matrix renormalization group for transfer matrices and analytically for $T\ll 1$ by field theoretical methods. Finally we compare $χ_B$ at finite temperature with a low-temperature asymptotics which we obtain by combining our Bethe ansatz result with recent predictions from bosonization.22 pages, 8 figuresStrongly Correlated Electronstext