Neglecting polydispersity degrades propensity measurements in supercooled liquids
arXiv:2012.09025 · doi:10.1140/epje/s10189-021-00049-2
Abstract
We conduct molecular dynamics simulations of a bidisperse Kob-Andersen (KA) glass former, modified to add in additional polydispersity. The original KA system is known to exhibit dynamical heterogeneity. Prior work defined propensity, the mean motion of a particle averaged over simulations reconstructing the initial positions of all particles but with randomized velocities. The existence of propensity shows that structure and dynamics are connected. In this paper, we study systems which mimic problems that would be encountered in measuring propensity in a colloidal glass former, where particles are polydisperse (they have slight size variations). We mimic polydispersity by altering the bidisperse KA system into a quartet consisting of particles both slightly larger and slightly smaller than the parent particles in the original bidisperse system. We then introduce errors into the reconstruction of the initial positions that mimic mistakes one might make in a colloidal experiment. The mistakes degrade the propensity measurement, in some cases nearly completely; one no longer has an isoconfigurational ensemble in any useful sense. Our results show that a polydisperse sample is suitable for propensity measurements provided one avoids reconstruction mistakes.
Implications for hypothetical colloidal experiment to test propensity
References in corpus (9)
- The role of local structure in dynamical arrest
- Irreversible reorganization in a supercooled liquid originates from localised soft modes
- Direct measurements of growing amorphous order and non-monotonic dynamic correlations in a colloidal glass-former
- Growing Dynamical Facilitation on Approaching the Random Pinning Colloidal Glass Transition
- Locally preferred structures and many-body static correlations in viscous liquids
- Structural and dynamical heterogeneity in a glass forming liquid
- On the relationship between structure and dynamics in a supercooled liquid
- Can the packing efficiency of binary hard spheres explain the glass-forming ability of bulk metallic glasses?
- Are there localized saddles behind the heterogeneous dynamics of supercooled liquids?