Dynamical density functional theory with hydrodynamic interactions and colloids in unstable traps

TL;DR

This paper develops a density functional theory incorporating hydrodynamic interactions to analyze colloidal particles in unstable traps, showing how these interactions dampen oscillations and match simulation results.

Contribution

It introduces a new theoretical framework for colloidal dynamics that includes hydrodynamic interactions in unstable trapping scenarios.

Findings

Hydrodynamic interactions significantly damp density oscillations.

The theory's predictions align well with Brownian dynamics simulations.

Hydrodynamic effects reduce the amplitude of density breathing modes.

Abstract

A density functional theory for colloidal dynamics is presented which includes hydrodynamic interactions between the colloidal particles. The theory is applied to the dynamics of colloidal particles in an optical trap which switches periodically in time from a stable to unstable confining potential. In the absence of hydrodynamic interactions, the resulting density breathing mode, exhibits huge oscillations in the trap center which are almost completely damped by hydrodynamic interactions. The predicted dynamical density fields are in good agreement with Brownian dynamics computer simulations.