Binary mixtures of active Brownian particles with distinct nonzero activities

Area of Science:

• Active matter physics
• Soft condensed matter
• Statistical mechanics

Background:

• Active Brownian particles (ABPs) are fundamental models for self-propelled entities.
• Motility-induced phase separation (MIPS) in ABPs leads to emergent collective behaviors.
• Mixtures of ABPs with different activities are less explored but relevant to diverse systems.

Purpose of the Study:

• Investigate the steady-state behavior of binary mixtures of active Brownian particles with varying activities.
• Explore the emergent properties and phase behavior modulated by activity ratios.
• Uncover the underlying microscopic mechanisms driving the observed macroscopic phenomena.

Main Methods:

• Computational study of active Brownian particle suspensions.
• Systematic variation of activity ratios (Pe^R) between slow and fast particles.
• Analysis of macroscopic properties (density, pressure) and microscopic domain structures.

Main Results:

• Identified three distinct regimes characterized by unique emergent behaviors based on activity ratio.
• Observed non-monotonic behavior of macroscopic properties with changing activity ratios.
• Discovered microphase separation, increased interfacial fluctuations, and significant avalanche events.

Conclusions:

• The activity ratio is a crucial parameter that dictates the emergent behavior of binary ABP mixtures.
• Simultaneously varying activities reveals complex phenomena not seen in monodisperse systems.
• This work provides a foundation for understanding and designing active matter systems with tunable properties.