Narrow escape for active camphor particles: facilitated escape and aging.

Abstract

In this work, we experimentally investigate the narrow escape problem using self-propelled camphor-infused discs, which have the possibility to escape from a bounded circular domain through an opening in the boundary. To analyze the statistical properties of the escape problem, we proposed two experimental protocols: first, a control setup within a closed circular domain where the disc encounters a target simulating an opening on the boundary, and a second setup where a real opening is placed on the boundary of the circular domain. These two setups allow us to compare how the statistical properties of escape differ between simulated (or fictitious) escape and the actual escape of camphor particles. Our results suggest that the presence of an actual opening in the wall alters the interactions between the particle and the boundary. Notably, we observe the counterintuitive phenomenon that introducing a real door in the boundary makes less accessible the escape from the domain. We further contrast and analyze several qualitative and quantitative properties of the system, including chiral flips, bouncing behavior, arrival angle distribution, as well as first passage time and exit time distributions, among other dynamical properties.