Critical amplitude ratio of the susceptibility in the randomsite twodimensional Ising model
Abstract
We present a different way of probing the universality class of the sitediluted twodimensional Ising model. We analyze Monte Carlo data for the magnetic susceptibility, introducing a fitting procedure in the critical region applicable even for a single sample with quenched disorder. This gives us the possibility to fit simultaneously the critical exponent, the critical amplitude, and the sampledependent pseudocritical temperature. The critical amplitude ratio of the magnetic susceptibility is seen to be independent of the concentration q of the empty sites for all investigated values of q<=0.25. At the same time the average effective exponent γ_{eff} is found to vary with the concentration q, which may be argued to be due to logarithmic corrections to the power law of the pure system. These corrections are canceled in the susceptibility amplitude ratio as predicted by theory. The central charge of the corresponding field theory was computed and compared well with the theoretical predictions.
 Publication:

Physical Review E
 Pub Date:
 December 2001
 DOI:
 10.1103/PhysRevE.65.016107
 arXiv:
 arXiv:condmat/0108369
 Bibcode:
 2001PhRvE..65a6107S
 Keywords:

 05.10.Ln;
 05.50.+q;
 64.60.Fr;
 75.10.Hk;
 Monte Carlo methods;
 Lattice theory and statistics;
 Equilibrium properties near critical points critical exponents;
 Classical spin models;
 Condensed Matter  Statistical Mechanics;
 Condensed Matter  Disordered Systems and Neural Networks;
 High Energy Physics  Lattice
 EPrint:
 6 pages, 4 figures