"Symmetry breaking and mode selection in soft and active matter systems"
This event is part of the Physics Department Colloquia Series.
Geometric constraints can profoundly affect pattern selection, topological defect formation and collective dynamics in equilibrium and non-equilibrium systems. In this talk, I will summarize recent experimental and theoretical work that aims to understand (i) how substrate curvature controls symmetry breaking and defect statistics in elastic surface crystals, (ii) how confinement geometry affects the spontaneous flows of microbial suspensions, and (iii) how negative friction induces mode selection in active network models. First, we will consider phenomenological parallels between 2D elastic and colloidal crystals on curved surfaces that suggest some universality in the underlying nucleation processes. Subsequently, we demonstrate how microbial flow patterns can be controlled by microstructure to realize bacterial spin lattices and flow networks. We conclude by showing that inherent micro-scale activity can produce interesting collective mode selection effects in generic transport network models with spectral band gaps.