Aggregation-disorder transition induced by fluctuating random forces

The author investigated the motion of many non-interacting particles with inertia in a viscous medium subject to an external, random force field that varied both in space and time. By varying parameters in the problem, it was found that there is a transition between two regimes. One regime, characterised by low mass or high viscosity, leads to the aggregation of particles. The other regime, high mass or low friction, leads to a complete lack of aggregation. The transition between these two regimes is marked by a discontinuous change in the order parameters defined for this problem. The relation between this work and previous work on iterated functions is discussed.