RANDOM-BOND ISING CHAIN IN A TRANSVERSE MAGNETIC-FIELD - A FINITE-SIZE-SCALING ANALYSIS

We investigate the zero-temperature quantum phase transition of the random-bond Ising chain in a transverse magnetic field. Its critical properties are identical to those of the McCoy-Wu model, which is a classical Ising model in two dimensions with layered disorder. The latter is studied via Monte Carlo simulations and transfer matrix calculations and the critical exponents are determined with a finite-size scaling analysis. The magnetization and susceptibility obey conventional rather than activated scaling. We observe that the order parameter and correlation function probability distribution show a nontrivial scaling near the critical point, which implies a hierachy of critical exponents associated with the critical behavior of the generalized correlation lengths.