Stochastic search processes and chemical reactivity in heterogeneous media

Intermittent search processes alternate between two different stochastic motions in order to reach a given target. If the faster motion has a lower probability to detect the target, a question arises concerning the efficiency of both processes, and it may be possible to minimize the search time by a convenient choice of the parameters. This argument has been used to interpret observations in molecular biology or to explain the behavior of animals when searching for food. It can also have interesting consequences for the kinetics of reactions in heterogeneous media. In particular, the reaction kinetics in a biological cell can be enhanced when the active molecules occasionally bind to molecular motors that inactivate their reactivity and carry them far away. Here, we present a synthesis of the recent results obtained on these topics, with new perspectives and possible applications of intermittent behavior in reaction kinetics to be soon developed.