- Conference date: 2–7 December 2012
- Location: Sendai, Japan
Nonlinear active micro-rheology in a glass-forming soft-sphere mixture is studied using molecular dynamics computer simulation. To this end, a single tracer particle is pulled through the system by applying a constant force of magnitude f. After the tracer particle has reached a steady state moving with a constant velocity ν, the incoherent intermediate scattering function F s(q, t) of the tracer is determined and analyzed for the directions parallel and perpendicular to the force with respect to its dependence on wavenumber q, time t, temperature T, and force strength f (note that due to the drift motion of the tracer particle, F s(q, t) in parallel direction is a complex quantity). We find pronounced anisotropies in F s(q,t) at low values of q; here, in parallel direction both the real and imaginary part of the incoherent intermediate scattering function, ReF s(q,t) and ImF s(q, t), may show an oscillatory behavior and ReF s(q,t) in perpendicular direction decays much more slowly than the corresponding function in parallel direction. Approaching values of q that correspond to microscopic scales the anisotropies in ReF s(q, t) vanish. In the latter regime, the decay of ReF s(q, t) is similar to that of a tagged particle in the quiescent equilibrium state.
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