Fundamental differences between glassy dynamics in two and three dimensions

TL;DR

This study reveals fundamental differences in glassy dynamics between two- and three-dimensional fluids, challenging the assumption that the glass transition is similar across dimensions, with key distinctions in particle localization and relaxation behaviors.

Contribution

The paper demonstrates that glassy dynamics in 2D and 3D are fundamentally different, highlighting the absence of transient localization in 2D and decoupled relaxation times, which was previously unrecognized.

Findings

Transient localization absent in 2D

Decoupled relaxation times in 2D

Different relationships between heterogeneity size and relaxation time

Abstract

The two-dimensional freezing transition is very different from its three-dimensional counterpart. In contrast, the glass transition is usually assumed to have similar characteristics in two and three dimensions. Using computer simulations we show that glassy dynamics in supercooled two- and three-dimensional fluids are fundamentally different. Specifically, transient localization of particles upon approaching the glass transition is absent in two dimensions, whereas it is very pronounced in three dimensions. Moreover, the temperature dependence of the relaxation time of orientational correlations is decoupled from that of the translational relaxation time in two dimensions but not in three dimensions. Lastly, the relationships between the characteristic size of dynamically heterogeneous regions and the relaxation time are very different in two and three dimensions. These results strongly suggest that the glass transition in two dimensions is different than in three dimensions.