  We present new results and give a concise review of recent previous results
on the asymptotics for large spin of the low-lying spectrum of the
ferromagnetic XXZ Heisenberg chain with kink boundary conditions. Our main
interest is to gain detailed information on the interface ground states of this
model and the low-lying excitations above them. The new and most detailed
results are obtained using a rigorous version of bosonization, which can be
interpreted as a quantum central limit theorem.
