title: Three-dimensional randomly dilute Ising model: Monte Carlo results.
abstract: We perform a high-statistics simulation of the three-dimensional randomly dilute Ising model on cubic lattices L3 with L< or =256. We choose a particular value of the density, x=0.8, for which the leading scaling corrections are suppressed. We determine the critical exponents, obtaining nu=0.683(3), eta=0.035(2), beta=0.3535(17), and alpha=-0.049(9), in agreement with previous numerical simulations. We also estimate numerically the fixed-point values of the four-point zero-momentum couplings that are used in field-theoretical fixed-dimension studies. Although these results somewhat differ from those obtained using perturbative field theory, the field-theoretical estimates of the critical exponents do not change significantly if the Monte Carlo result for the fixed point is used. Finally, we determine the six-point zero-momentum couplings, relevant for the small-magnetization expansion of the equation of state, and the invariant amplitude ratio R(+)(xi) that expresses the universality of the free-energy density per correlation volume. We find R(+)(xi)=0.2885(15).
authors.affiliation: Scuola Normale Superiore and INFN, Piazza dei Cavalieri 7, I-56126 Pisa, Italy. calabres@df.unipi.it
authors.forename: Pasquale
authors.initials: P
authors.lastname: Calabrese
authors.forename: Victor
authors.initials: V
authors.lastname: Martín-Mayor
authors.forename: Andrea
authors.initials: A
authors.lastname: Pelissetto
authors.forename: Ettore
authors.initials: E
authors.lastname: Vicari