Critical behavior of the three-dimensional dilute Ising antiferromagnet in a field.

We report results of large Monte Carlo simulations of an experimentally realizable random field system: the three-dimensional dilute Ising antiferromagnet in a field. As the critical temperature is approached from above, the correlation time diverges very rapidly; the results are consistent with a proposed new type of activated dynamic scaling. The transition appears to be continuous, with effective critical exponents 2-eta = 1.5 +- 0.1 and 2-eta = 3.0 +- 0.3 for the connected and disconnected staggered susceptibilities, respectively. These exponents satisfy recently derived inequalities.