S. K. Kumar | Searcharxiv

arXiv2004

Enhanced cooperativity below the caging temperature of glass-forming liquids

The utility of a cooperative length scale for describing the dynamics of small molecule glass-formers is shown. Molecular Dynamics and Monte Carlo simulations reveal a distribution of cooperatively moving fractal events below the temperature Ta at which dynamics become caged. Guided by these results, four straightforward methods emerge to recognize Ta in experimental data and quantify the length scale that grows on cooling below Ta. This length scale is consistent with 4-D NMR experiments which are sensitive to the slow moving population.

cond-mat.other↗

arXiv2003

An exploding glass ?

We propose a connection between self-similar, focusing dynamics in nonlinear partial differential equations (PDEs) and macroscopic dynamic features of the glass transition. In particular, we explore the divergence of the appropriate relaxation times in the case of hard spheres as the limit of random close packing is approached. We illustrate the analogy in the critical case, and suggest a ``normal form'' that can capture the onset of dynamic self-similarity in both phenomena.

cond-mat↗