  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.
