Narrow escape for active camphor particles: facilitated escape and aging

Area of Science:

• Physics
• Statistical Mechanics
• Complex Systems

Background:

• The narrow escape problem is crucial in various fields, including biology and physics.
• Understanding particle dynamics near boundaries is essential for predicting escape phenomena.
• Self-propelled particles offer a unique model system for studying complex escape behaviors.

Purpose of the Study:

• To experimentally investigate the narrow escape problem using self-propelled camphor discs.
• To compare escape statistics between simulated and actual openings in a circular domain.
• To analyze how boundary openings influence particle-boundary interactions and escape dynamics.

Main Methods:

• Utilizing self-propelled camphor-infused discs in a bounded circular domain.
• Implementing two experimental protocols: a control with a simulated opening and a setup with a real opening.
• Analyzing statistical properties such as first passage time, exit time distributions, and arrival angle distributions.

Main Results:

• A real opening paradoxically reduces escape accessibility compared to a simulated opening.
• The presence of an actual opening significantly alters particle-boundary interactions.
• Observed phenomena include chiral flips, bouncing behavior, and distinct arrival angle distributions.

Conclusions:

• Actual openings create unique boundary conditions that impede escape, contrary to intuition.
• Particle-boundary interactions are fundamentally different in real versus simulated escape scenarios.
• This study provides novel insights into the statistical physics of escape phenomena in active matter systems.