Speaker
Description
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 [1]. I will first discuss two examples of these collective features helping us understand biological processes: (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 [2], and (ii) how self-propelled defects lead to finding an unanticipated mechanism for cell death [3,4].
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 [5]. I will also explain how combining hydrodynamics with topological constraints can lead to further control of exotic morphologies of active shells [6].
[1] A. Amiri, R. Mueller, and A. Doostmohammadi, J. Phys. A. (2021).
[2] O. J. Meacock et al., Nat. Phys. (2021).
[3] T. N. Saw et al., Nature. (2017).
[4] R. Mueller, J. M. Yeomans, and A. Doostmohammadi, Phys. Rev. Lett. (2019).
[5] A. Doostmohammadi et al., Nat. Comm. (2018).
[6] L. Metselaar, J. M. Yeomans, and A. Doostmohammadi, Phys. Rev. Lett. (2019).
