2008/10/15 by I. Gazuz, A. M. Puertas, Th. Voigtmann +1 · 1 citation
Physics and Astronomy · #cond-mat.soft
paper · pdf · doi:10.1103/physrevlett.102.248302
published as Physical Review Letters 102, 248302 (2009)
arxiv created 2008/10/15 · arxiv updated 2009/12/01
We present a first-principles theory for the active nonlinear microrheology of colloidal model systems: for constant external force on a spherical probe particle embedded in a dense host dispersion, neglecting hydrodynamic interactions, we derive an exact expression for the friction. Within mode-coupling theory (MCT), we discuss the threshold external force needed to delocalize the probe from a host glass, and its relation to strong nonlinear velocity-force curves in a host fluid. Experimental microrheology data and simulations, which we performed, are explained with a simplified model.