Binding self-propelled topological defects in active turbulence

TL;DR

This paper demonstrates the formation of stable, self-propelled bound defects in active nematic monolayers, revealing complex interactions between active stresses and particle flow alignment that lead to novel defect structures.

Contribution

It introduces the concept of stable self-propelled bound defects in active nematics, supported by simulations and analytical insights, expanding understanding of defect dynamics.

Findings

Stable self-propelled bound defects can form in active nematics.

The formation depends on active stresses and flow-aligning behavior.

New defect structures may inspire further experiments and theories.

Abstract

We report on the emergence of stable self-propelled bound defects in monolayers of active nematics, which form virtual full-integer topological defects in the form of vortices and asters. Through numerical simulations and analytical arguments, we identify the phase-space of the bound defect formation in active nematic monolayers. It is shown that an intricate synergy between the nature of active stresses and the flow-aligning behaviour of active particles can stabilise the motion of self-propelled positive half-integer defects into specific bound structures. Our findings uncover new complexities in active nematics with potential for triggering new experiments and theories.