Inertia effects in the spatial distribution and dynamics of active particles with space-dependent activity

Area of Science:

• Soft Matter Physics
• Active Matter Systems
• Statistical Mechanics

Background:

• Active particles exhibit unique behaviors influenced by external conditions like light.
• Spatially varying activity causes active particles to accumulate in low-activity zones, forming polarity layers.
• Understanding particle inertia is crucial for predicting active matter dynamics.

Purpose of the Study:

• Investigate the distribution and dynamics of inertial active particles in alternating active and passive regions.
• Analyze the impact of high inertia on particle behavior at interfaces and within regions.
• Explore emergent phenomena such as depletion and anti-polarity layers, and anomalous diffusion.

Main Methods:

• Simulations of individual and ideal gas of inertial particles.
• Analysis of particle distribution, velocity autocorrelation functions, and mean squared displacement.
• Examination of kinetic temperature and pressure gradients across regions.

Main Results:

• High inertia induces a depletion layer in passive regions and an anti-polarity layer at active-passive interfaces.
• Interfacial polarity layers can reverse orientation under specific conditions (narrow regions, long persistence times).
• High-inertia particles show superdiffusive behavior (∼t3) and velocity autocorrelation peaks > 1 in active regions.

Conclusions:

• Spatially modulated activity significantly alters inertial active particle behavior, creating complex interfacial structures.
• Inertia plays a critical role in emergent phenomena like depletion layers and anomalous transport.
• Findings provide a foundation for studying interacting inertial active particles and their collective behaviors.