Diffusion, subdiffusion, and trapping of active particles in heterogeneous media

Area of Science:

• Physics
• Soft Matter Physics
• Statistical Mechanics

Background:

• Active particles exhibit complex transport behaviors in confined or heterogeneous environments.
• Understanding particle dynamics in the presence of obstacles is crucial for various applications.

Purpose of the Study:

• To investigate the transport properties of active particles in a 2D heterogeneous space with obstacles.
• To analyze the influence of obstacle density and particle turning speed on particle motion.

Main Methods:

• Numerical simulations were employed to model particle trajectories.
• Analytical calculations were performed to derive key transport parameters.
• Mean square displacement was analyzed as a function of obstacle density and turning speed.

Main Results:

• Particle motion shows two distinct regimes based on obstacle density and turning speed (γ).
• At low γ, diffusive motion occurs with a diffusion coefficient minimum at intermediate obstacle density.
• High obstacle density and large γ lead to spontaneous particle trapping and subdiffusive motion.

Conclusions:

• Active particle transport is significantly altered by spatial heterogeneity and turning speed.
• The observed phenomena can be leveraged for designing active particle filters.
• This study provides insights into fundamental transport mechanisms in complex media.