Super-Arrhenius slowing down in the metastable liquid of hard spheres

It is demonstrated that a straightforward extension of the Arrhenius law accurately describes diffusion in the thermodynamically stable liquid of hard spheres. A sharp negative deviation from this behaviour is observed as the liquid is compressed beyond its stability limit, which can be compared with super-Arrhenius slowing down in supercooled liquids. It is suggested that the observed dynamical transition is caused by extra entropy barriers arising in the free-energy landscape. This interpretation is corroborated by the observation of characteristic anomalies in the geometry of a particle trajectory.