Real space renormalization group study of the random bond Ising model

The effects of configurational, quenched, bond randomness on the critical properties of the nearest-neighbour Ising model are studied in two and three dimensions by a real space renormalization group method. Correlations between the random bonds generated by the renormalization group transformation are taken into account approximately. This proves necessary in order to obtain correct scaling behaviour, i.e., crossover exponent λ = α/ν. The transition temperature is calculated approximately as a function of the bond variance.