Field-driven tracer diffusion through curved bottlenecks: fine structure of first passage events

Area of Science:

• Physics
• Physical Chemistry
• Statistical Mechanics

Background:

• Understanding particle transport in confined geometries is crucial for various scientific fields.
• Corrugated channels with bottlenecks present complex dynamics for diffusing particles.
• Existing models like the Fick-Jacobs approach may oversimplify particle behavior in such systems.

Purpose of the Study:

• To investigate the dynamics of a tracer particle in a corrugated channel with funnel-like bottlenecks.
• To analyze the distribution of first crossing heights and first passage times.
• To identify dynamical features missed by traditional approaches.

Main Methods:

• Utilizing scaling arguments for theoretical insights.
• Performing extensive numerical simulations to model particle trajectories.
• Analyzing probability distributions for crossing events and passage times.

Main Results:

• Tracer particle trajectories concentrate near the funnel boundary.
• First-crossing events are highly sensitive to binding sites and microscopic roughness.
• Identified novel dynamical behaviors beyond the Fick-Jacobs approximation.

Conclusions:

• The detailed analysis provides a more accurate understanding of particle dynamics in complex channels.
• The findings highlight the importance of boundary interactions and surface properties.
• This work offers new perspectives for modeling transport phenomena in nanoconfinement.