Role of Friction in Multidefect Ordering

Area of Science:

• Soft Matter Physics
• Non-equilibrium Systems
• Complex Fluids

Background:

• Active nematics exhibit spontaneous self-organization and defect formation.
• +1/2 defects in frictionless systems align antiparallel and associate with flow vortices.
• Understanding defect dynamics is crucial for predicting active matter behavior.

Purpose of the Study:

• To investigate the influence of friction on defect ordering in active nematics.
• To elucidate the mechanisms driving large-scale structure formation.
• To analyze the interplay between defect interactions and packing geometries.

Main Methods:

• Continuum simulations were employed to model the active nematic system.
• The effects of varying friction levels on defect behavior were systematically studied.
• Analysis focused on defect positional and orientational ordering.

Main Results:

• In frictionless systems, +1/2 defects align antiparallel and form flow vortices.
• Increasing friction strengthens defect-defect interactions, leading to enhanced ordering.
• Dynamically evolving, large-scale ordered structures emerge under higher friction.
• Observed ordering results from a competition between hexagonal and rectangular packing preferences of different defect types.

Conclusions:

• Friction is a key parameter controlling defect ordering in active nematics.
• Enhanced defect interactions due to friction drive the formation of complex, large-scale structures.
• The competition between packing preferences dictates the emergent order.