Berlin 2015 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 12: Granular Matter / Contact Dynamics Part II

DY 12.2: Vortrag

Montag, 16. März 2015, 15:45–16:00, BH-N 128

DWS measurements on fluidized granular media — •Philip Born, Steffen Reinhold, and Matthias Sperl — DLR Institute of Materials Physics in Space, Cologne, Germany

Diffusing wave spectroscopy (DWS) measurements indicate glass-like dynamics in dense, fluidized granular media close to jamming. This suggests fundamental similarities among the jamming transition in granular media and the glass transition in other fluid systems. However, the glass-like dynamics appear as a localization of the mean-squared displacement of the particles on length scales of a few 10 nm. Such length scales are not present in measurements using complementary techniques. In order to confirm the present results, we perform DWS measurements in microgravity, which promises isotropic agitation. Additionally, we tailor particle interactions to test the influence of long-ranges and short-ranged interactions. The results indicate that DWS measurements have to be evaluated with care, as omnipresent particle interactions prevent pure hard-sphere behavior, and incoherent intensity fluctuations put in question the localization interpretation of the intensity fluctuations.