Active Ornstein-Uhlenbeck model for self-propelled particles with inertia

Area of Science:

• Physics
• Statistical Mechanics
• Soft Matter Physics

Background:

• Self-propelled particles convert energy to motion.
• Macroscopic or gas-phase particles exhibit inertia, unlike smaller particles in viscous fluids.
• The active Ornstein-Uhlenbeck model describes particle dynamics.

Purpose of the Study:

• Extend the active Ornstein-Uhlenbeck model to include inertial effects.
• Analyze particle dynamics under various external influences.
• Investigate the impact of time-dependent mass on particle motion.

Main Methods:

• Utilized an extended active Ornstein-Uhlenbeck model with colored noise.
• Derived analytical solutions for mean-squared displacement and velocity autocorrelation.
• Examined scenarios including free particles, potentials, and inter-particle coupling.

Main Results:

• Observed dynamical exponents ranging from zero to four, influenced by initial velocity.
• Inertia's effect diminishes over time, reverting to overdamped behavior, except in harmonic potentials.
• Harmonically confined systems show enhanced displacement due to inertia.

Conclusions:

• Inertia significantly alters self-propelled particle dynamics, particularly in confined or non-stationary scenarios.
• Time-dependent mass can lead to persistent superdiffusive motion.
• The study provides insights into the fundamental physics of active matter.