Mimicking magnets with lattices of bacterial vortices
Speaker : Dr Francis Woodhouse – Cambridge University
Venue : Thu 7 Apr 2016 @ 4pm, Murdoch University, room ECL1.031 (below ECL2.031)
When alone in an unbounded fluid, a rod-shaped motile bacterium like E. coli will swim in straight lines punctuated by random turns. Pack many of them together in the same fluid, however, and they adopt collective swirling patterns akin to macroscopic turbulence. Confining the bacteria within a small circular cavity tames this turbulence and leads instead to a steadily spinning bacterial vortex. If many such vortices are then linked together in a square lattice of cavities, the rotation sense of a vortex becomes dependent on those of its neighbours. By declaring the senses to be ‘up’ and ‘down’ spins, the result is a bacterial analogue of an Ising ferromagnet. After explaining the background to these so-called ‘active matter’ systems, I will explore the challenges involved in mapping classical statistical physics models to this decidedly non-classical system – but only after revealing an entirely unexpected twist in the experiments.
nce in biomedical materials, including polymer processing, surgery, nanotechnology and surface science. Originally from Perth, Australia, and trained as a materials scientist, he was part of a successful team in the 1990s taking an artificial cornea from concept to the clinic. Paul post-docced at the University of Toronto, Canada, and RWTH Aachen, Germany, working in neural tissue engineering and applying nanotechnology to life science applications. As an independent fellow at the University of Southampton, he invented melt electrospinning writing as a new 3D printing technology and performed experimental surgery to understand the neuroinflammation of hydrogels in the spinal cord. Between 2010 and 2013, he split his time between Shanghai Jiao Tong University in China and Queensland University of Technology in Australia. Paul has an H-Index of 36 from only 70 research articles published in journals including Advanced Materials, Progress in Polymer Science, Nature Communications and Nature Materials.