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Active matter commensuration and frustration effects on periodic substrates
C Reichhardt1, C J O Reichhardt1
1Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
Physical Review. E
|March 19, 2021
Summary
Active matter systems show unique commensuration effects with periodic obstacles, unlike passive Brownian motion. Varying obstacle size leads to crystalline or disordered states, revealing new physics in self-driven particle behavior.
Area of Science:
- Soft Matter Physics
- Active Matter Systems
- Statistical Mechanics
Background:
- Brownian motion describes passive particle dynamics, limited by thermal fluctuations.
- Active matter, composed of self-driven units, exhibits complex emergent behaviors.
- Commensuration effects, seen in systems like superconductors and colloids, arise from periodic interactions.
Purpose of the Study:
- To investigate active matter commensuration effects in a system of self-driven particles interacting with a periodic obstacle array.
- To compare these effects with those observed in the passive Brownian limit.
- To analyze the influence of obstacle size and particle activity on emergent states and ordering.
Main Methods:
- Simulations of self-driven particles interacting with a tunable periodic obstacle array.
- Analysis of particle motility, phase separation, and ordering.
- Introduction of an external drift force to probe system mobility.
Main Results:
- Active matter systems display distinct commensuration effects absent in the Brownian limit.
- Varying obstacle size induces transitions between crystalline, frustrated, and amorphous states.
- Commensuration correlates with peaks in sixfold ordering and maximum cluster size.
- System mobility exhibits characteristic peaks and dips under drift force, mirroring phenomena in superconducting vortices and colloidal particles.
Conclusions:
- Periodic obstacle arrays can induce novel commensuration effects in active matter.
- These effects are strongly dependent on particle activity and obstacle geometry.
- The findings offer insights into the collective behavior and transport properties of active matter systems.
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