J. Abad et M. Rios, METHOD FOR SOLVING INTEGRABLE A(2) SPIN CHAINS COMBINING DIFFERENT REPRESENTATIONS, Physical review. B, Condensed matter, 53(21), 1996, pp. 14000-14003
A nonhomogeneous spin chain in the representations {3} and {3} of A(2
) is analyzed. We find that the naive nested Bethe ansatz is not appli
cable to this case. A method inspired in the nested Bethe ansatz that
can be applied to more general cases is developed for that chain. The
solution for the eigenvalues of the trace of the monodromy matrix is g
iven as two coupled Bethe equations different from that for a homogene
ous chain. A conjecture about the form of the solutions for more gener
al chains is presented.