Colloids Exposed to Random Potential Energy Landscapes: from Particle Number Density to Particle-Potential and Particle-Particle Interactions

TL;DR

This study investigates how colloidal particles behave in a randomly generated optical potential landscape, measuring particle distributions and correlations, and comparing results with theoretical predictions to understand disorder effects.

Contribution

It introduces experimental measurements of particle density correlations and an Edwards-Anderson order parameter in colloids within a random potential, aligning with replica liquid state theory.

Findings

Disorder-averaged pair density correlation function measured.

Experimental validation of the Edwards-Anderson order parameter.

Consistency with replica liquid state theory results.

Abstract

Colloidal particles were exposed to a random potential energy landscape (rPEL) that has been created optically via a speckle pattern. The mean particle density as well as the potential roughness, i.e. the disorder strength, were varied. The local probability density of the particles as well as its main characteristics were determined. For the first time, the disorder-averaged pair density correlation function and an analogue of the Edwards-Anderson order parameter, which quantifies the correlation of the mean local density among disorder realisations, were measured experimentally and shown to be consistent with replica liquid state theory results.