Effects of spatial heterogeneities on the slow dynamics of density fluctuations near the colloidal glass transition

The effects of spatial heterogeneities on the slow dynamics of density fluctuations are discussed both in an equilibrium colloidal suspension and in a slightly nonequilibrium colloidal suspension. The long-lived, heterogeneous glassy domains appear near the glass transition and influence the dynamics of density fluctuations, leading to the α- and β-relaxation processes. The spatial heterogeneities related to the β process are less noticeable in an equilibrium case than in a nonequilibrium case. Thus, a logarithmic decay is shown to be a new critical decay in an equilibrium case, instead of the power-law decay followed by the von Schweidler decay in a nonequilibrium case.