First-Passage Times of Intermittent Random Walks

Abstract

This chapter discusses intermittent target search strategies, which combine phases of slow motion, allowing a searcher to detect a target, and phases of fast motion during which targets cannot be detected. It is first shown that such intermittent random walks are widely observed at various scales, ranging from animals looking for food to the intermittent transport patterns involved in the search for a specific sequence on DNA by a protein. Next, generic stochastic models are introduced, which show that intermittent random walks are efficient strategies that enable the minimization of the mean first-passage time to a target. This suggests that the intrinsic efficiency of intermittent search strategies could justify their frequent observation in nature.