*********************************
There is now a CONTENT FREEZE for Mercury while we switch to a new platform. It began on Friday, March 10 at 6pm and will end on Wednesday, March 15 at noon. No new content can be created during this time, but all material in the system as of the beginning of the freeze will be migrated to the new platform, including users and groups. Functionally the new site is identical to the old one. webteam@gatech.edu
*********************************
Certain non-equilibrium systems, including growing microbial colonies, amorphous solids under oscillatory shear, turbulent liquid crystals, and avalanches undergo dynamical phase transitions across which we observe fluctuating, active regions of the system either propagate and grow with time, or go extinct, forcing the system into an absorbing state.
We will focus on such transitions in two very different systems: a microbial colony in which a fit strain irreversibly converts to a less fit one (leading to the possibility of strain extinction), and a dense, amorphous solid under oscillatory shear. In the case of the microbial colony, we show that the spatial distribution and geometry of the colony profoundly impacts the phase transition, with spatial fluctuations driving extinction of the fit strain.
In the driven amorphous solid, we show that the dynamical phase transition competes with another phase transition at which the solid loses rigidity: the jamming point. We show that as the jamming point is approached, the absorbing states associated with reversible, quiescent dynamical behavior become more and more complex.