To elucidate slow dynamics in glassy materials, we introduce the figure-8 model in which N hard blocks undergo Brownian motion around a circuit in the shape of a figure 8. This system undergoes kinetic arrest at a critical packing fraction I = I g <1, and for I g long-time diffusion is controlled by rare, cooperative, "junction-crossing" particle rearrangements. We find that the average time between junction crossings τJC, and hence the structural relaxation time, does not simply scale with the configurational volume Ωc of transition states, because τJC also depends on the time to complete a junction crossing. The importance of these results in understanding cage-breaking dynamics in glassy systems is discussed.
|Journal||Physical Review E - Statistical, Nonlinear, and Soft Matter Physics|
|State||Published - Jul 16 2008|