DYNAMICS OF THE SYMMETRICALLY CONSTRAINED ISING CHAIN

The dynamics of the symmetrically constrained Ising spin chain, or sym metric one-spin facilitated kinetic Ising model, is investigated both by Monte Carlo simulation and by analytical mode-expansion methods. We confirm Fredrickson's argument that at low concentration of the facil itating up spins, the dynamics is governed by the diffusion of isolate d up spins, but only for very low up-spin concentrations c less than o r equal to 10(-3). An adequate analytical treatment is obtained by a t hree-spin approximation, which describes the diffusion of pairs of iso lated up spins.