Active matter, in which sustained energy transduction takes place at the scale of the constituent particles, is an important part of the physicist's answer to the question "What Is Life?" This emerging area of nonequilibrium physics has yielded insights into mechanics and statistics in living matter with a surprising recurrence of similar themes across widely disparate scales. I will present a unifying theoretical framework and make a surprising connection to some striking phenomena in sedimentation. I will then present highlights of our recent work on the (in)stability of active fluids, density fluctuations in active nematics, and flocking and collective trapping in artificial motile matter. 

The Colloquium Ehrenfestii takes place on Wednesday evenings starting at 19:30 hours in the main auditorium of the Oort building. Before the Colloquium, there is a common dinner in the canteen located on the ground floor of the  Oort building. The dinner starts at 18:00 hours sharp and is free of charge, under the condition that one attends the colloquium and that one has made a reservation before noon on the Tuesday preceding the colloquium. The registration form is only accessible from within the University (to block spammers); if you would like to register for the dinner from outside the University, please send an email to fran@lorentz.leidenuniv.nl

The revolving doors to the Oort building  are accessible until 9 pm after that they are locked and one should instead use the sliding