Hydrodynamic interactions induce anomalous diffusion under partial confinement

摘要

Under partial confinement, the motion of colloidal particles is restricted toa plane but their dynamics is influenced by hydrodynamic interactions mediatedby the unconfined, three--dimensional flow of the embedding fluid. Wedemonstrate that this dimensionality mismatch induces a characteristicdivergence in the two--dimensional collective diffusion coefficient of thecolloidal monolayer. This result, independent from the specific interparticleforces in the monolayer, is solely due to the kinematical constraint on thecolloidal particles, and it is different from the known divergence of transportcoefficients in purely two--dimensional fluids.