From single particle motion to collective dynamics in Janus motor systems

Area of Science:

• Chemical Physics
• Soft Matter Physics
• Statistical Mechanics

Background:

• Janus motors are active particles that exhibit directed motion due to chemical reactions on their surfaces.
• Nonequilibrium systems, where energy is continuously supplied, display unique emergent behaviors not seen in equilibrium.
• Understanding the interplay between motor dynamics, fluid interactions, and chemical reactions is key to controlling active matter.

Purpose of the Study:

• To investigate the single-particle and collective dynamics of Janus motors in nonequilibrium states.
• To analyze the influence of reversible catalytic reactions and intermolecular interactions on motor behavior.
• To explore the conditions leading to the formation of dynamic clusters in ensembles of Janus motors.

Main Methods:

• Theoretical analysis of single-particle dynamics under external forces.
• Application of finite-time fluctuation theorems to nonequilibrium reactive fluctuations.
• Computer simulations of collective dynamics for small ensembles of Janus motors.

Main Results:

• Reaction rates for single Janus motors show nonlinear dependence on external forces far from equilibrium.
• Nonequilibrium reactive fluctuations of moving motors are described by a fluctuation formula for fixed catalytic particles.
• Collective dynamics simulations reveal spatial and orientational correlations in dynamic cluster states.

Conclusions:

• Janus motor systems in nonequilibrium states exhibit complex dynamics driven by catalytic reactions and external forces.
• The study elucidates the onset of dynamical clustering and the instability of homogeneous distributions.
• These findings provide insights into the fundamental principles governing active matter self-organization.