Single-file diffusion of interacting particles in a finite-sized channel

Area of Science:

• Physics
• Soft Matter Physics
• Statistical Mechanics

Background:

• Understanding particle dynamics in confined geometries is crucial for various physical phenomena.
• Macroscopic particle behavior under thermal fluctuations in narrow channels presents unique challenges.

Purpose of the Study:

• To investigate the dynamics of charged macroscopic particles in a finite linear channel.
• To identify and characterize different dynamical regimes based on particle position and local potential.
• To develop a heuristic model for describing particle fluctuations and mobility.

Main Methods:

• Experimental study of millimetric steel balls in a narrow linear channel.
• Analysis of particle dynamics, diffusion coefficients, and mobility under thermal fluctuations.
• Development of a heuristic model based on interacting particles in a finite channel.

Main Results:

• Identified three distinct dynamical regimes: free, correlated (single-file-like), and saturated fluctuations.
• Observed that particle response to thermal fluctuations depends on position and local potential.
• Found that mobility increases with local potential in the correlated regime.
• Developed a model using a characteristic distance that accurately estimates fluctuation sizes.

Conclusions:

• Particle dynamics in confined channels are strongly influenced by position-dependent thermal fluctuations and local potentials.
• The proposed heuristic model provides a satisfactory description of particle fluctuation sizes, outperforming hard-core interaction models.
• The study offers insights into the complex behavior of macroscopic particles in constrained environments.