A set of exactly solvable Ising models with half-odd-integer spin
Abstract
We present a set of exactly solvable Ising models, with half-odd-integer spin-S on a square-type lattice including a quartic interaction term in the Hamiltonian. The particular properties of the mixed lattice, associated with mixed half-odd-integer spin-(S,1/2) and only nearest-neighbour interaction, allow us to map this system either onto a purely spin-1/2 lattice or onto a purely spin-S lattice. By imposing the condition that the mixed half-odd-integer spin-(S,1/2) lattice must have an exact solution, we found a set of exact solutions that satisfy the {\it free fermion} condition of the eight vertex model. The number of solutions for a general half-odd-integer spin-S is given by . Therefore we conclude that this transformation is equivalent to a simple spin transformation which is independent of the coordination number.
Cite
@article{arxiv.0805.0572,
title = {A set of exactly solvable Ising models with half-odd-integer spin},
author = {Onofre Rojas and S. M. de Souza},
journal= {arXiv preprint arXiv:0805.0572},
year = {2009}
}