Statistical physics of random searches

Abstract

We apply the theory of random walks to quantitatively describe the general problem of how to search efficiently for randomly located objects that can only be detected in the limited vicinity of a searcher who typically has a finite degree of "free will" to move and search at will. We illustrate Levy flight search processes by comparison to Brownian random walks and discuss experimental observations of Lévy flights in the special case of biological organisms that search for food sites. We review recent findings indicating that, an inverse square probability density distribution P(ℓ) ∼ ℓ-2 of step lengths ℓ can lead to optimal searches. Finally we survey the explanations put forth to account for these surprising findings.