The exact solution and the finite-size behaviour of the Osp(1|2)-invariant spin chain

Abstract

We have solved exactly the Osp(1|2) spin chain by the Bethe ansatz approach. Our solution is based on an equivalence between the Osp(1|2) chain and a certain special limit of the Izergin-Korepin vertex model. The completeness of the Bethe ansatz equations is discussed for a system with four sites and the appearance of special string structures is noted. The Bethe ansatz presents an important phase factor which distinguishes the even and odd sectors of the theory. The finite-size properties are governed by a conformal field theory with central charge c = 1.