Experimental observations of fractal landscape dynamics in a dense emulsion

Many soft and biological materials display so-called 'soft glassy' dynamics; their constituents undergo anomalous random motions and complex cooperative rearrangements. A recent simulation model of one soft glassy material, a coarsening foam, suggested that the random motions of its bubbles are due to the system configuration moving over a fractal energy landscape in high-dimensional space. Here we show that the salient geometrical features of such high-dimensional fractal landscapes can be explored and reliably quantified, using empirical trajectory data from many degrees of freedom, in a model-free manner. For a mayonnaise-like dense emulsion, analysis of the observed trajectories of oil droplets quantitatively reproduces the high-dimensional fractal geometry of the configuration path and its associated local energy minima generated using a computational model. That geometry in turn drives the droplets' complex random motion observed in real space. Our results indicate that experimental studies can elucidate whether the similar dynamics in different soft and biological materials may also be due to fractal landscape dynamics. Experimental study of a mayonnaise-like dense emulsion shows evidence of fractal energy landscape dynamics, confirming results of a recent computational model.

Automated summary

A recent study showed that the random motions of the bubbles in a soft glassy material are due to the configuration of the system moving over a fractal energy landscape in high-dimensional space. The analysis of the observed trajectories of oil droplets in a dense emulsion reproduced the high-dimensional fractal geometry of the configuration path and confirmed the presence of fractal energy landscape dynamics. This discovery suggests that similar dynamics in different soft and biological materials may also be attributed to fractal landscape dynamics.