Defect annihilation and proliferation in active nematics

Phys Rev Lett. 2013 May 31;110(22):228101. doi: 10.1103/PhysRevLett.110.228101. Epub 2013 May 29.


Liquid crystals inevitably possess topological defect excitations generated through boundary conditions, through applied fields, or in quenches to the ordered phase. In equilibrium, pairs of defects coarsen and annihilate as the uniform ground state is approached. Here we show that defects in active liquid crystals exhibit profoundly different behavior, depending on the degree of activity and its contractile or extensile character. While contractile systems enhance the annihilation dynamics of passive systems, extensile systems act to drive defects apart so that they swarm around in the manner of topologically well-characterized self-propelled particles. We develop a simple analytical model for the defect dynamics which reproduces the key features of both the numerical solutions and recent experiments on microtubule-kinesin assemblies.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Hydrodynamics
  • Kinesin / chemistry
  • Liquid Crystals / chemistry*
  • Microtubules / chemistry
  • Models, Chemical*
  • Solutions / chemistry


  • Solutions
  • Kinesin