  We use x-ray photon correlation spectroscopy to investigate the dynamics of a
high volume fraction emulsion creaming under gravity. The dodecane-in-water
emulsion has interfaces stabilized solely by colloidal particles (silica). The
samples were observed soon after mixing: as the emulsion becomes compact we
discern two regimes of ageing with a cross-over between them. The young
emulsion has faster dynamics associated with creaming in a crowded environment
accompanied by local rearrangements. The dynamics slow down for the older
emulsion although our studies show that motion is associated with large
intermittent events. The relaxation rate, as seen from the intensity
autocorrelation function, depends linearly on the wave vector at all times;
however, the exponent associated with the line shape changes from 1.5 for young
samples to less than 1 as the emulsion ages. The combination of ballisticlike
dynamics, an exponent that drops below 1 and large intermittent fluctuations
has not been reported before.
