Non-equilibrium steady states in active motile matter, a talk by Professor Tanniemola Liverpool (University of Bristol)
Abstract
Colonies of swimming bacteria, algae or spermatozoa are examples of active systems composed of interacting units that consume energy and collectively generate motion and mechanical stresses. Due to the anisotropy of their interactions, these active particles can exhibit orientational order at high concentrations and have been called “living liquid crystals”. Biology at the cellular and multicellular scale provides numerous examples of these active systems. We will describe some recent theoretical work developing a framework for characterising the behaviour of active particle systems.
We show that the concept of a steady state, well known for systems at equilibrium, must be generalised to describe driven, fluctuating physical systems such as active matter systems. In these, the steady state is associated with a stationary probability density of micro-states and a deterministic dynamical system whose trajectories the system follows on average. These trajectories are a manifestation of non-stationary macroscopic currents observed in these systems. We determine precise conditions for the steady state to exist as well as the requirements for it to be stable. Finally we illustrate this with the example of recent experimental and theoretical work studying collections of electrically-driven colloidal rollers moving in two dimensions.
This talk will be given remotely, via Zoom. If you wish to register for attendance at this Scottish branch talk, please contact Gemma Reeves before 3.00pm on the day of the talk, who will provide the required details.
No charge is made to attend meetings. Non-IMA members are welcome.
