Inertial delay of self-propelled particles.

Area of Science:

• Physics
• Active Matter Physics
• Statistical Mechanics

Background:

• Self-propelled particles in gaseous media are typically modeled neglecting inertia.
• Inertial effects are crucial in systems like vibrated granulates, complex plasmas, and flying insects.

Purpose of the Study:

• To experimentally demonstrate the significance of inertia in macroscopic self-propelled particles.
• To investigate the influence of inertial delay on the dynamics of active matter.

Main Methods:

• Experimental observation of macroscopic self-propelled particles.
• Analysis of the relationship between particle orientation and velocity.
• Theoretical explanation using an underdamped Langevin model of active Brownian motion.

Main Results:

• Observed a distinct inertial delay between particle orientation and velocity.
• Attributed this delay to finite relaxation times within the system.
• Demonstrated that this effect is fully explained by the generalized Langevin model.

Conclusions:

• Inertia profoundly influences the long-time dynamics of active matter, unlike in passive systems.
• The inertial delay enables novel fundamental strategies for controlling self-propelled motion.