Detecting temporal correlations in hopping dynamics in Lennard–Jones liquids. (12th August 2022)

• Record Type: Journal Article
• Authors: Sposini, Vittoria; Chechkin, Aleksei V; Sokolov, Igor M; Roldán-Vargas, Sándalo
• Is Part Of: Journal of physics. Volume 55:Number 32(2022)
• Publication Date: 2022-08-12
• Subjects: glassy systems -- hopping dynamics -- jump detection -- rare events; Mathematical physics -- Periodicals; Statistical physics -- Periodicals; Quantum theory -- Periodicals; Matter -- Properties -- Periodicals; 530.105
• DOI: 10.1088/1751-8121/ac7e0a
• Languages: English
• ISSNs: 1751-8113

Abstract

Abstract: Lennard–Jones mixtures represent one of the popular systems for the study of glass-forming liquids. Spatio/temporal heterogeneity and rare (activated) events are at the heart of the slow dynamics typical of these systems. Such slow dynamics is characterised by the development of a plateau in the mean-squared displacement (MSD) at intermediate times, accompanied by a non-Gaussianity in the displacement distribution identified by exponential tails. As pointed out by some recent works, the non-Gaussianity persists at times beyond the MSD plateau, leading to a Brownian yet non-Gaussian regime and thus highlighting once again the relevance of rare events in such systems. Single-particle motion of glass-forming liquids is usually interpreted as an alternation of rattling within the local cage and cage-escape motion and therefore can be described as a sequence of waiting times and jumps. In this work, by using a simple yet robust algorithm, we extract jumps and waiting times from single-particle trajectories obtained via molecular dynamics simulations. We investigate the presence of correlations between waiting times and find negative correlations, which becomes more and more pronounced when lowering the temperature.