Structure and dynamics of glass formers: predictability at large length scales.

Dynamic heterogeneity in glass formers has been related to their static structure using the concept of dynamic propensity. We reexamine this relationship by analyzing dynamical fluctuations in two atomistic glass formers and two theoretical models. We introduce quantitative statistical indicators which show that the dynamics of individual particles cannot be predicted on the basis of the propensity or by any structural indicator. However, the spatial structure of the propensity field does have predictive power for the spatial correlations associated with dynamic heterogeneity. Our results suggest that the quest for a connection between the static and dynamic properties of glass formers at the particle level is in vain, but they demonstrate that such a connection does exist on larger length scales.