Pattern-induced local symmetry breaking in active-matter systems

What is it about?

The emergence of both macroscopic order and spatiotemporal patterns are hallmarks of active-matter systems. Recently it was observed experimentally that patterns of polar and nematic symmetries can be firmly intertwined: they can coexist, interact and even dynamically transform into each other (Huber et al, Science, 2018). We propose a general mechanism for this sort of phenomenology that is based on pattern-induced local symmetry breaking. Our results not only provide new insights into pattern formation in active matter but also reveal a novel mutual feedback mechanism between pattern formation and symmetry breaking. We are convinced that this feedback is not limited to our specific study, but is very probably a more general principle that comes into play whenever a control parameter (such as density) is dynamically redistributed during pattern formation. This could apply to a broad range of biological and synthetic active-matter systems with chemical interactions (e.g. collective sensing in bacteria) and behavioural adaptation (e.g. in social learning).

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Photo by Solen Feyissa on Unsplash

Photo by Solen Feyissa on Unsplash