Design rules for controlling active topological defects.

Area of Science:

• Physics of active matter
• Soft condensed matter physics
• Non-equilibrium statistical mechanics

Background:

• Topological defects are crucial in various materials like magnets and liquid crystals.
• In active fluids, defects act as self-propelled particles, driving chaotic flows.
• Controlling defect spatiotemporal behavior is key to engineering active materials, but design principles are lacking.

Purpose of the Study:

• To propose a symmetry-based additive strategy for precise control of topological defects in active fluids.
• To establish design principles for the spatiotemporal manipulation of active defects.
• To demonstrate the creation, movement, and braiding of defects using active topological tweezers.

Main Methods:

• Theoretical modeling based on symmetry principles.
• Computational simulations of active fluid dynamics.
• Utilizing spatial activity gradients as 'electric fields' for defect manipulation.

Main Results:

• Demonstrated an additive strategy using active topological tweezers to control defects.
• Showcased how spatial activity gradients induce inverted topological polarization of defects.
• Successfully patterned and transported interacting active defects in a dynamic setting.

Conclusions:

• An additive framework for sculpting flows and manipulating active defects in space and time has been established.
• This approach enables the design of programmable active and living materials.
• Potential applications include transport, memory, and logic devices.