Superaging in two-dimensional random ferromagnets

We study the aging properties, in particular the two-time autocorrelations, of the two-dimensional randomly diluted Ising ferromagnet below the critical temperature via Monte Carlo simulations. We find that the autocorrelation function displays additive aging C(t,t(w))=C-st(t)+C-ag(t,t(w)), where the stationary part C-st decays algebraically. The aging part shows anomalous scaling C-ag(t,t(w))=C[h(t)/h(t(w))], where h(u) is a nonhomogeneous function excluding a t/t(w) scaling.