Dynamics of an Ising-like model in four space dimensions

Using a molecular-dynamics technique, we studied the excitation spectrum of an Ising-like lattice-dynamic model in four space dimensions. We found a central peak close to the transition temperature which does not evolve from the damped soft mode. Our results reveal that the overdamped-soft-mode picture and current interpretations of renormalization-group results for dynamic properties should be revised. They also provide testable predictions for Ising-like dipolar systems. © 1978 The American Physical Society.