Fluctuations in liquids and glasses

In a coarsened description of glassformers, the fluctuating variable is the local order. The configuration space of a glassformer consists of many basins with basin boundaries determined by heights of the potential energy landscape. We suggest that structural changes in the system may be described in terms of local rearrangements as elementary inter-basin steps. A general theorem is found relating the fluctuations of the local structure to thermodynamic properties measured at different time scales.