Three Body Fluctuation-Induced Interaction at Fluid Interfaces: A Strong Deviation from the Pairwise Summation

TL;DR

This paper introduces a scattering-based method to analyze fluctuation-induced forces at fluid interfaces, revealing significant deviations from pairwise summation in three-body interactions, especially between frozen and fluctuating colloids.

Contribution

The study develops a novel scattering technique that includes boundary fluctuations to accurately analyze many-body fluctuation-induced forces at fluid interfaces.

Findings

Significant deviation from pairwise summation in three-body interactions.

Marked differences in free energy between frozen and fluctuating colloids.

Good agreement between analytical and numerical results.

Abstract

We present a new method based on the scattering technique to investigate fluctuation-induced forces at a fluid interface. The scattering approach, well suited to the study of many body systems of arbitrary geometries, is augmented to include boundary fluctuations. Using this method, we study the deviation of the total fluctuation-induced interaction from the sum of pairwise energies for three colloidal particles. We consider both frozen and fluctuating colloids and obtain a very good agreement between analytical and numerical results. We find a marked difference in the three body fluctuation-induced free energy between the frozen and fluctuating colloids, both in sign and relative size.