Subcritical jump probability and anomalous order parameter autocorrelations

Abstract

We study the magnetization dynamics in finite 2D and 3D Ising lattices of size N for temperatures T just below the pseudo-critical temperature T pc (N) when the free energy, as a function of the mean magnetization M, possesses doubly degenerate minima at . We calculate the jump probability P LR between the microstate-subspaces with M < 0 (L) and M > 0 (R). We find a universal law for the decay of P LR as a function of . We show that for a given simulation time there is a temperature below which the mean number of jumps becomes less than . Below the two microstate-subspaces become practically disconnected. We observe an anomalous enhancement of the magnetization autocorrelations for T approaching which can be explained as a transition from type I (at ) to on-off (at ) intermittency in the magnetization effective dynamics. Possible phenomenological implications of this behaviour are briefly discussed.