Abstract
We consider the open XXZ quantum spin chain with nondiagonal boundary terms. For bulk anisotropy value
η=
iπ
p+1
,
p=1,2,…, we propose an exact (
p+1)-order functional relation for the transfer matrix, which implies Bethe-ansatz-like equations for the corresponding eigenvalues. The key observation is that the fused spin-
p+1
2
transfer matrix can be expressed in terms of a lower-spin transfer matrix, resulting in the truncation of the fusion hierarchy.
