On the integrability of the S=1 quantum spin chain with pure biquadratic exchange

Abstract

States of the pure biquadratic S=1 quantum spin chain with more than one deviation are considered. An expression for the wave function for an interacting pair of 2-strings has been calculated in the Bethe ansatz form. It is shown that there is a partial mapping of states of multiple 2-strings onto the states of the anisotropic S=1/2 quantum spin chain (XXZ model) which is known to be integrable. The mapping does not include the ground state, however. Other types of state with multiple deviations are also discussed.