First-Passage Times and Target Search Strategies

old_uid4097
titleFirst-Passage Times and Target Search Strategies
start_date2008/02/15
schedule09h
onlineno
summaryHow long does it take for a "searcher" to reach a target" point for the first time? This first-passage time is actually a key quantity for evaluating the spreading of diseases, the kinetics of diffusion limited reactions, or the time needed for animals to find food resources. I will first show that intermittent search strategies, which combine phases of active perception and phases of mere displacement constitute efficient strategies that allow to minimize the search time. I will rely on two examples at very different scales: the search for a specific target sequence on DNA by a protein, and the foraging strategies of animals. In a second part, I will present recent results which permit to evaluate precisely the mean first-passage time for a wide range of random searchers evolving in a confined domain. This approach reveals a universal dependence of the mean first-passage time on the geometric characteristics of the problem. I will briefly show how these results apply to transport in fractal and disordered media, and to anomalous diffusion.
responsiblesBourgine