FUSION PROCEDURE FOR OPEN CHAINS

We have recently generalized Sklyanin's approach of constructing open integrable quantum spin chains to the case of PT-invariant R matrices. Here we formulate a fusion procedure for such chains. In particular, we show that the fused transfer matrix can be expressed in terms of products of the original transfer matrix and products of certain quantum determinants which can be explicitly evaluated. Applications of these results include constructing open integrable higher-spin chains, as well as obtaining functional equations for transfer-matrix eigenvalues, which may be solved by an analytical Bethe ansatz.