THE 2-DIMENSIONAL SITE-DILUTED ISING FERROMAGNET - A DAMAGE-SPREADINGANALYSIS

The quenched site-diluted Ising ferromagnet on a square lattice, for w hich each site is occupied or empty with probabilities p and 1 - p, re spectively, is studied numerically through damage-spreading procedures . By making use of the Glauber dynamics, the percolation threshold p(c ) is estimated. Within the heat-bath dynamics, the damage-spreading te mperatures T-d(p) (for several values of p > p(c)) are computed, indic ating a strong correlation with the corresponding critical temperature s T-c(p). A procedure for estimating the fractal dimensions of cluster s of damaged sites, at low temperatures, is presented; as p --> p(c), our estimate is very close to 91/48, which is the fractal dimension of the infinite cluster at p = p(c) in two-dimensional site percolation. Whenever possible to compare, our results are in good agreement with the best estimates available from other techniques, in spite of a mode st computational effort.