A Dynamical Systems Perspective on Phase Separation
- Event time: 1:00pm
- Event date: 19th September 2008
- Speaker: Juergen Vollmer (MPI Dynamics & Self-Organization Goettingen)
- Location: Room 2511, James Clerk Maxwell Building (JCMB) James Clerk Maxwell Building Peter Guthrie Tait Road Edinburgh EH9 3FD GB
From the point of view of dynamical systems a binary mixture situated not too far inside the coexistence region can be viewed as a bistable system, which is marginally stable to changes of temperature. The single-phase system is metastable, and in a phase-separated system there will be a slow diffusive mass exchange between the phases. What happens for moderate temperature ramps with a fixed mass exchange rate? For weak gravity a saddle-node bifurcation marks the breakdown of steady diffusion. In the presence of gravity this breakdown may be preceded by convection. The threshold values for both instabilities can be calculated analytically, and mean-field arguments are given to show that in parameter regimes of typical applications one should expect secondary oscillatory instabilies.
This is a weekly series of informal talks given primarily by members of the soft condensed matter and statistical mechanics groups, but is also open to members of other groups and external visitors. The aim of the series is to promote discussion and learning of various topics at a level suitable to the broad background of the group. Everyone is welcome to attend..