8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

P5.70Wed 711:10-14:00Dynamics of individual colloidal particles in quenchedand time-dependent random potentialsRichard Hanes, 1 Michael Schmiedeberg, 1 Hartmut Loewen, 1 and Stefan Egelhaaf 11 Heinrich-Heine-Universität Düsseldorf, Universitätsstr. 1, 40225, Düsseldorf,GermanyThe behaviour of individual colloidal particles in a sequentially updated random potential hasbeen studied via experiment, simulation and theory. Video microscopy was used to observe themotion of colloidal particles in a 1D optically generated random potential [1]. Each instanceof the potential was drawn from a Gaussian distribution, the width of which was varied betweenmeasurements, and the potential refreshed with a range of frequencies. The particle dynamics havebeen studied over many orders of magnitude in time and have been characterised using the MeanSquared Displacement and the Non-Gaussian Parameter. The dynamics are initially diffusive withan extended sub-diffusive regime at intermediate times before recovering diffusive motion at longtimes. The experimental results have been compared with Monte Carlo simulations and theory. Wehave extended the theoretical predictions of the characteristic time scales and mobilities to covernot only the asymptotic regime [2] but also intermediate times. The experiments, simulations andtheory display good agreement over the whole time range.[1] Hanes, R. D. L. , Jenkins, M. C. ; Egelhaaf, S. U. , Rev. Sci. Instrum. , 80, 083703 (2009).[2] Zwanzig, R. , Proc. Natl. Acad. Sci. , 85, 2029-2030 (1988).70