It is shown that there is a hidden connection between the two well-studied sequences of the Temperley-Lieb (TL) integrable models -- the
q-state quantum Potts (QP) models at the self-dual points and the staggered
SU(n) spin-
s chains with
n=2s+1 (
s≥1), in addition to the uniform
SU(2) spin-
1/2 Heisenberg model. For each sequence, symmetry group factorization arises, in the sense that if
q is factorized into
q1 and
q2, then the
q-state QP model is unitarily equivalent to a combined QP model with the symmetry group
Sq1×Sq2 or if
n is factorized into
n1 and
n2, then the staggered
SU(n) spin-
s chain with the symmetry group
SU(n) is unitarily equivalent to a combined staggered
SU(n1)×SU(n2) spin chain with the symmetry group
SU(n1)×SU(n2), valid for both ferromagnetic (FM) and antiferromagnetic (AF) cases. Moreover, the FM (AF) staggered
SU(n) spin-
s chain is unitarily equivalent to the AF (FM)
q-state QP model with
q=n2, as long as the size of the AF (FM) staggered
SU(n) spin-
s chain is doubled. A combination of the two distinct types of unitary equivalences yields a family of models such that they are essentially identical, but appear in different guises. Some physical implications for unitary equivalence among different TL integrable models are clarified.
The generalization of the Yang-Baxter equations in the presence of ℤ 2 grading along both chain and time directions is presented and an integrable model of t - J type with staggered disposition of shifts of the spectral parameter along the chain is constructed. The Hamiltonian of the model is computed in the fermionic formulation. It involves three neighbour site interactions and therefore can be considered as a zigzag ladder model. The algebraic Bethe ansatz technique is applied and the eigenstates as well as the eigenvalues of the transfer matrix of the model are found. It is argued that in the thermodynamic limit the lowest energy of the model is formed by the quarter filling of the states by fermions instead of the usual half filling.
The generalization of the Yang-Baxter equations (YBE) in the presence of Z_2 grading along both chain and time directions is presented and an integrable model of t-J type with staggered disposition along a chain of shifts of the spectral parameter is constructed. The Hamiltonian of the model is computed in fermionic formulation. It involves three neighbour site interactions and therefore can be considered as a zig-zag ladder model. The Algebraic Bethe Ansatz technique is applied and the eigenstates, along with eigenvalues of the transfer matrix of the model are found. In the thermodynamic limit, the lowest energy of the model is formed by the quarter filling of the states by fermions instead of usual half filling.