Active microrheology in active matter systems: Mobility, intermittency, and avalanches.

Area of Science:

• Physics
• Soft Matter Physics
• Statistical Mechanics

Background:

• Active matter systems exhibit complex emergent behaviors driven by self-propulsion.
• Understanding particle dynamics in these systems is crucial for predicting collective phenomena.

Purpose of the Study:

• To investigate the mobility and velocity fluctuations of a driven particle in an active matter bath.
• To correlate particle dynamics with emergent spatiotemporal structures.
• To identify distinct dynamic regimes, including activity-induced crystallization and active jamming.

Main Methods:

• Simulating a driven particle interacting with a bath of self-mobile disks.
• Varying system parameters such as particle density and activity levels.
• Analyzing particle mobility, velocity distributions, and spatiotemporal structures.

Main Results:

• Observed nonmonotonic behavior in driven particle mobility linked to structural changes.
• Identified an activity-induced uniform crystallization at moderate activity.
• Characterized a cluster phase with telegraph noise velocity distributions at higher activity.
• Described an active jamming regime at high densities and activities, exhibiting power-law distributed avalanche dynamics.

Conclusions:

• Driven particle dynamics in active matter are sensitive to density and activity, leading to diverse emergent phases.
• The study reveals novel dynamic regimes like activity-induced crystallization and active jamming.
• Findings provide insights into fundamental transport phenomena in non-equilibrium systems.