CMSA Active Matter: Taming Active Matter: from ordered topological defects to autonomous shells


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February 24, 2022 1:00 pm - 2:00 pm
via Zoom Video Conferencing

Amin Doostmohammadi - Niels Bohr Institute, University of Copenhagen

The spontaneous emergence of collective flows is a generic property of active fluids and often leads to chaotic flow patterns characterized by swirls, jets, and topological

disclinations in their orientation field. I will first discuss two examples of these collective features helping us understand biological processes:

  1. (i) to explain the tortoise & hare story in bacterial competition: how motility of Pseudomonas aeruginosa bacteria leads to a slower invasion of bacteria colonies, which are individually faster, and
  2. (ii) how self-propelled defects lead to finding an unanticipated mechanism for cell death.

I will then discuss various strategies to tame, otherwise chaotic, active flows, showing how hydrodynamic screening of active flows can act as a robust way of controlling and guiding active particles into dynamically ordered coherent structures. I will also explain how combining hydrodynamics with topological constraints can lead to further control of exotic morphologies of active shells.

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