Department of Physics, City College of the CUNY, New York, NY 10031, USA
Abstract:
This is a study of the equilibrium statistical mechanics of a mixed system of planar spins and Ising spins. The Ising spins σr are situated (one on each of the bonds connecting the planar spins sr so that the planar spins interact only via Ising spins. For a one-dimensional lattice the partition function and the two-spin correlation functions (σrσr1 and Sr·Sr1) are calculated ex actly in terms of modified Bessel functions.
For a two-dimensional anisotropic generalization of the model an equation is given for the critical temperature and the equation is shown to have one and only one solution Tc such that 0<Tc<∞.