Fluctuations and scaling in aggregation phenomena

We introduce a method which enables us to isolate different sources of fluctuations during a typical aggregation process. As an example, we focus on the evolution of islands during irreversible submonolayer epitaxy. We show that only spatial fluctuations in island nucleation are required to produce the scaling of their size distribution as determined by Monte Carlo simulations. In particular, once the islands are seeded, their growth can be described in a purely deterministic manner.