Twist-Induced Networking and Fast Propagation of Defects in Three-Dimensional Active Nematics.

Area of Science:

• Soft Matter Physics
• Active Matter Systems
• Topological Defects

Background:

• Active nematics generate spontaneous topological defects driven by continuous energy input.
• These defects typically exhibit chaotic motion governed by active hydrodynamics.

Purpose of the Study:

• To investigate the structure and dynamics of topological defects in 3D active nematics.
• To explore the effects of boundary twisting, analogous to twisted bilayer graphene, on defect behavior.

Main Methods:

• Theoretical modeling and numerical simulations were employed.
• The study analyzed the impact of varying twist angles on defect patterns and dynamics.

Main Results:

• Increasing twist angle induces a transition from wedge-twist defect loops to pure-twist defect lines.
• Defect lines self-organize into oscillating networks that propagate as waves.
• The observed wave speed significantly exceeds local active flow speeds.

Conclusions:

• Boundary twisting profoundly influences 3D active nematic defect dynamics.
• Fast defect wave propagation arises from activity-driven pattern transitions and nematic elasticity-mediated oscillations.
• This provides a strategy for programming 3D defect dynamics.