Lawrence Berkeley National Laboratory

Clusters in the three-dimensional Ising model rigorously obey reducibility and thermal scaling up to the critical temperature. The barriers extracted from Arrhenius plots depend on the cluster size as $B \propto A^ sigma$ wqwhere $\ sigma$ is a critical exponent relating the cluster size to the cluster surface. All the Arrhenius plots collapse into a single Fisher-like scaling function indicating liquid-vapor-like phase coexistence and the univarian equilibrium between percolating clusters and finite clusters. The compelling similarity with nuclear multifragmentation is discussed.