Dr Rastko Sknepnek

20. April 2022.

You are cordially invited to the Center for solid state physics and new materials seminar, which will be held on Friday, June 15th 2018 at 15:00 in the library reading room “Dr Dragan Popović” of the Institute of Physics Belgrade. The talk entitled

Active matter and Curvature

will be given by Dr Rastko Sknepnek, University of Dundee, United Kingdom.


Coupling between active motion and curvature is an integral
part of many fundamental biological processes such as gastrulation and
intestinal crypt fission. However, to date very little is known about
how curvature affects active motion. Here we use a particle-based model
to study the interplay between activity and curvature in dense systems.
Using detailed numerical simulations and simple physical arguments, we
show that the presence of curvature results in a number of steady-state
configurations that have no analogues in flat geometries. These states
are particularly interesting if topological constraints require the
presence of defects in the ground states in the passive limit. We focus
on polar and nematic active systems confined to move on the surface of a
sphere and show that activity can lead to the formation of moving band
and multidefect states. We extend our model to self-propelled filaments
confined to a plane or the surface of a sphere. We show that the
activity leads to an effective softening of the polymer chain. As a
result of this softening, with the increase in activity, the system
transitions between a jammed polymer-melt state, an active turbulent
state characterised by a proliferation of hair-pin defects, to a region
dominated by phase segregation (MIPS), finally followed by the onset of
a homogenous state characterised by spiral motion of individual