Integrable generalized spin ladder models based on the SU(1|3) and SU(3|1) algebras

Abstract

The Schwinger SU (3) We present two integrable spin ladder models which possess a general free parameter besides the rung coupling J. The models are exactly solvable by means of the Bethe ansatz method and we present the Bethe ansatz equations. We analyze the elementary excitations of the models which reveal the existence of a gap for both models that depends on the free parameter.

Bethe ansatz equations and exact S matrices for the osp(M|2n) open super-spin chain

“…in [13] (thermodynamical aspects), [14] (diagonal boundary K matrices) and [15] (boundary S-matrix). Extended Hubbard models were considered in [16] (closed chain) and in [17,18,19] (open chains with integrable boundary conditions), whilst spin ladder systems associated to some sl(m|n) superalgebras were obtained in [20,21]. General results for continuum limit of the gl(m|n) super spin chains were derived in [22].…”

Exactly soluble isotropic spin-½ ladder models

“…[1] the su(4) and su(3|1)-invariant integrable Hamiltonians have been constructed on the basis of the solution of the Yang-Baxter equation (R-matrix), given in terms of the corresponding permutation operator. Multiparametric models related to these symmetries have been considered in [2] and [3] while an extension to n-leg ladder models associated with the su(2 n ), o(2 n ) and sp(2 n ) algebras has been obtained in [4] and [5]. The R-matrix of the generalized ladder model [4,6] satisfy the Yang-Baxter equation with a multiplicative composition law.…”