Anomalous diffusion and quasistationarity in the HMF model

A. Pluchino, A. Rapisarda

Published 2007-11-12Version 1

We explore the quasistationary regime of the Hamiltonian Mean Field Model (HMF) showing that at least three different classes of events exist, with a different diffusive behavior and with a relative frequency which depends on the size of the system. Along the same line of a recent work \cite{epl}, these results indicate that one must be very careful in exchanging time averages with ensemble averages during the non-ergodic metastable regime and at the same time they emphasize the role of finite size effects in the evaluation of the diffusive properties of the system.