Experimental identification of topological defects in 2D colloidal glass.

Topological defects are singularities within a field that cannot be removed by continuous transformations. The definition of these irregularities requires an ordered reference configuration, calling into question whether they exist in disordered materials, such as glasses. However, recent work suggests that well-defined topological defects emerge in the dynamics of glasses, even if they are not evident in the static configuration.

Entropic timescales of dynamic heterogeneity in supercooled liquid.

Non-Gaussian displacement distributions are universal predictors of dynamic heterogeneity in slowly varying environments. Here, we explore heterogeneous dynamics in supercooled liquid using molecular dynamics simulations and show the efficiency of the relative-entropy based measure, negentropy, in quantifying dynamic heterogeneity over the widely used non-Gaussian parameter. Our analysis shows that the heterogeneity quantified by the negentropy is significantly different from the one obtained using the conventional moment-based definition that considers deviation from Gaussianity up to lower-order moments.

Finite-size effects in the diffusion dynamics of a glass-forming binary mixture with large size ratio.

Extensive molecular dynamics computer simulations of an equimolar, glass-forming AB mixture with a large size ratio are presented. While the large A particles show a glass transition around the critical density of mode-coupling theory ρ, the small B particles remain mobile with a relatively weak decrease in their self-diffusion coefficient D with increasing density. Surprisingly, around ρ, the self-diffusion coefficient of species A, D, also starts to show a rather weak dependence on density.

Rheological response of a glass-forming liquid having large bidispersity.

Using extensive numerical simulations, we investigate the flow behaviour of a model glass-forming binary mixture whose constituent particles have a large size ratio. The rheological response to applied shear is studied in the regime where the larger species are spatially predominant. We demonstrate that the macroscopic rigidity that emerges with increasing density occurs in the regime where the larger species undergo a glass transition while the smaller species continue to be highly diffusive.

Response of glassy liquids to thermal gradients.

The Soret effect, i.e., the flow of matter caused by a temperature gradient, is studied in a glass-forming binary Lennard-Jones (LJ) mixture, using nonequilibrium molecular dynamics computer simulation.