Integrable su(2)-invariant spin chains and the Haldane conjecture

Abstract

We perform a systematic exact algebraic search for integrable spin-S chains which are isotropic in spin space, i.e. are su(2)-invariant. The families of spin chains found for S < 14 support recent arguments in favour of the complete classification of all such integrable chains. The integrable families of spin chains are discussed in the light of the conjectured spin-dependent properties of the Heisenberg chain.