A higher-spin generalization of the XYZ spin chain defined by the fusion procedure is considered. The energy and momentum of the ground state and low-lying excited states of the model are computed by means of an isomorphism between a space of theta functions on which the Sklyanin algebra acts and a space obtained by the fusion procedure.
A generalization of the eight-vertex model by means of higher spin representations of the Sklyanin algebra is investigated by the quantum inverse scattering method and the algebraic Bethe ansatz. Under the well known string hypothesis low-lying excited states are considered and scattering phase shifts of two physical particles are calculated. The S-matrix of two-particle states is shown to be proportional to Baxter`s (1972) elliptic R-matrix with a different elliptic modulus from the original one.
The authors have generalized Sklyanin's approach of constructing open integrable quantum spin chains to the case of PT-invariant R matrices. They formulate a fusion procedure for such chains. In particular, they 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.
Generalized XYZ Model Associated to Sklyanin Algebra∗
The free energy of a lattice model, which is a generalization of the Heisenberg XYZ model with the higher spin representation of the Sklyanin algebra, is calculated by the generalized Bethe Ansatz of Takhtajan and Faddeev. (Talk given at the XXI Differential Geometry Methods in Theoretical Physics, Tianjin, China 5-9 June 1992)