TITLE: An Ising model with three-body interactions on the 3-12 lattice

                   Department of Theoretical Physics,
                   National Institute for Physics and Nuclear Engineering, Bucharest, 
                   POB MG-6, 76900, Romania

ABSTRACT:
 

We consider the standard Ising model (spin 1/2 nearset neighbours interactions) on the 3-12 lattice with an additional three body interaction term between the spins of the same $C_3$ graph. The model can be transformed into the standard Ising model on the honeycomb lattice via two transformations: a star traimgle followed by a double decoration. These transformations were previously derived in the case when the absolute value of the three-body interaction parameter is less than the two body coupling constant. A strong three body interaction term introduces a singularity in these transformations and we have to consider  complex values of the modela parameters on the intermediate lattice. We use the derived formulas to calculate the exacvt expressions of the spontaneous magnetization and the spin-spin correlation function for the considered model with arbitrary strong three-body interactions in terms of the standard Ising model quantities on the honeycomb lattice.

back