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Defect dynamics in clusters of self-propelled rods in circular confinement
Zhengjia Wang1, Tieyan Si2, Junhua Hao3
1Condensed Matter Science and Technology Institute, School of Instrumentation Science and Engineering, Harbin Institute of Technology, 150080, Harbin, P.R. China.
The European Physical Journal. E, Soft Matter
|November 28, 2019
Summary
Self-propelled rods (SPRs) exhibit collective behaviors like vortex and hedgehog patterns when confined. Increasing active force influences pattern transitions and energy relations, revealing topological charge dynamics.
Area of Science:
- Physics
- Soft Matter Physics
- Statistical Mechanics
Background:
- Active micro/nano-particles, like bacterial and metallic motors, display unique far-from-equilibrium collective phenomena.
- Self-propelled rods (SPRs) are model systems for studying active matter dynamics.
Purpose of the Study:
- To investigate the collectively ordered states of self-propelled rods (SPRs) confined in a circular zone.
- To explore the influence of active force on pattern formation and energy dynamics in SPR systems.
Main Methods:
- Utilized dissipative particle dynamics (DPD) simulations.
- Simulated self-propelled rods confined within a finite circular boundary.
- Analyzed emergent patterns and interaction energies as a function of active force (Fa).
Main Results:
- Observed successive pattern transitions: global vortex, vortex-hedgehog oscillation, and hedgehog patterns with increasing active force.
- Determined distinct energy-force relationships: U ∼ Fa for vortex patterns and U ∼ Fa2 for hedgehog patterns.
- Characterized the creation and annihilation of topological charges through the dynamic evolution of hedgehog patterns.
Conclusions:
- Active force is a critical parameter driving collective behavior and pattern transitions in confined SPR systems.
- The distinct energy scaling laws highlight fundamental differences in the organization of vortex and hedgehog states.
- The dynamics reveal a novel mechanism for topological defect manipulation in active matter systems.
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