Influence of hydrodynamic interactions on the dynamics of long-range interacting colloidal particles

We study the influence of hydrodynamic interactions on the self-diffusion of super paramagnetic colloidal particles suspended in water. The colloids interact via repulsive dipolar forces due to an applied magnetic field, and their motion is effectively confined to two dimensions. By comparing experimental data with the results from extensive computer simulations, where the water flow fields are treated at the Rotne-Prager level, we show that the diffusivity is enhanced at all times due to hydrodynamic interactions. The enhancement effect becomes stronger with increasing particle density, but is almost unaffected by the temperature.