Topology in Polar Flocking and Active Nematics - Mark Bowick

From Katie Gentilello April 30th, 2018

29 plays 0 comments

Active flocking on curved surfaces, such as the 2-sphere and the catenoid, exhibits dynamical symmetry breaking in the form of spontaneous flow, calculable inhomogeneous density patterns and long-wavelength propagating sound modes that get gapped by the curvature of the underlying substrate. Curvature and active flow together result in symmetry-protected topological modes that get localized to special geodesics on the surface. These modes are the analogue of edge states in electronic quantum Hall systems and provide unidirectional channels for information transport in the flock, robust against disorder and backscattering. Active nematics instead exhibit spontaneous motility of strength +1/2 disclinations and active torques that favor the motility-driven unbinding of defects. Despite the directed motion of defects, nematic order is stabilized by rotational noise at low enough activity. Within a perturbative treatment, active forces lower the effective defect-unbinding transition temperature.

9:40 – 10:20 Mark Bowick, Kavli Institute for Theoretical Physics, University of California, Santa Barbara.

https://mediaspace.gatech.edu/media/Perry+Ellis+-+MBowick_SMF_20180418/1_hbwqk2wq

Tags: spring 2018science and technology of advanced materials and interfaces (stami)symposium on soft matter forefrontsgeorgia techcollege of sciences

name: Mark Bowick
Date: April 18th, 2018
Appears In: Open Scholarship

Comments
Related Media

Loading…

Topology in Polar Flocking and Active Nematics - Mark Bowick

Related Media