2019/11/18 by D. S. Grebenkov, R. Metzler, G. Oshanin · 2 citations
Physics and Astronomy · Biochemistry, Genetics and Molecular Biology · #cond-mat.stat-mech #physics.bio-ph #q-bio.QM
paper · pdf · doi:10.1088/1367-2630/ab5de4
published as New J. Phys. 21, 122001 (2019) · 30 pages, 9 figures, IOPLaTeX
arxiv created 2019/11/18 · arxiv updated 2020/01/03
In the scenario of the narrow escape problem (NEP) a particle diffuses in a finite container and eventually leaves it through a small "escape window" in the otherwise impermeable boundary, once it arrives to this window and over-passes an entropic barrier at the entrance to it. This generic problem is mathematically identical to that of a diffusion-mediated reaction with a partially-reactive site on the container's boundary. Considerable knowledge is available on the dependence of the mean first-reaction time (FRT) on the pertinent parameters. We here go a distinct step further and derive the full FRT distribution for the NEP. We demonstrate that typical FRTs may be orders of magnitude shorter than the mean one, thus resulting in a strong defocusing of characteristic temporal scales. We unveil the geometry-control of the typical times, emphasising the role of the initial distance to the target as a decisive parameter. A crucial finding is the further FRT defocusing due to the barrier, necessitating repeated escape or reaction attempts interspersed with bulk excursions. These results add new perspectives and offer a broad comprehension of various features of the by-now classical NEP that are relevant for numerous biological and technological systems.