Diffusion of active Brownian particles under quenched disorder

Area of Science:

• Physics
• Statistical Mechanics
• Nonlinear Dynamics

Background:

• Active particles exhibit complex dynamics influenced by disorder and external forces.
• Understanding anomalous diffusion is crucial for modeling various physical and biological systems.
• Ergodicity breaking in disordered systems presents unique challenges in theoretical analysis.

Purpose of the Study:

• To investigate the anomalous diffusion of a single active particle in one dimension under quenched disorder and an external force.
• To analyze the characteristics of weak ergodicity breaking, specifically non-ergodic subdiffusion and superdiffusion.
• To elucidate the underlying mechanisms responsible for these diffusion behaviors.

Main Methods:

• Simulations of a single active particle model in one dimension.
• Analysis of time-dependent probability distributions for particle velocities and positions.
• Characterization of anomalous diffusion regimes (subdiffusion and superdiffusion).

Main Results:

• Observed anomalous diffusion, including non-ergodic subdiffusion and superdiffusion, within specific parameter ranges.
• Identified weak ergodicity breaking as a key feature of the observed diffusion.
• Attributed the diffusion behavior to the interplay between 'locked' and 'running' states of the particle.

Conclusions:

• The study provides a detailed analysis of anomalous diffusion in a driven disordered system.
• The findings highlight the role of particle states in governing non-ergodic transport.
• Results contribute to understanding self-propelled particle dynamics and nonlinear responses to external forces.