Potential Energy Landscape and Long Time Dynamics in a Simple Model Glass

TL;DR

This paper explores the potential energy landscape of a Lennard-Jones glass model, using a network approach to reproduce long-time dynamics and observe glassy behaviors like stretched exponential relaxation and FDT violations.

Contribution

It introduces a simple network-based model of the energy landscape that captures key glassy dynamics and off-equilibrium phenomena in a Lennard-Jones system.

Findings

Reproduces long-time dynamics of the glassy system.

Observes stretched exponential relaxation and temperature-dependent parameters.

Identifies a critical temperature with FDT violation.

Abstract

We analyze the properties of a Lennard-Jones system at the level of the potential energy landscape. After an exhaustive investigation of the topological features of the landscape of the systems, obtained studying small size sample, we describe the dynamics of the systems in the multi-dimensional configurational space by a simple model. This consider the configurational space as a connected network of minima where the dynamics proceeds by jumps described by an appropriate master equation. Using this model we are able to reproduce the long time dynamics and the low temperature regime. We investigate both the equilibrium regime and the off-equilibrium one, finding those typical glassy behavior usually observed in the experiments such as: {\it i)} stretched exponential relaxation, {\it ii)} temperature-dependent stretching parameter, {\it iii)} breakdown of the Stokes-Einstein relation, and {\it iv)} appearance of a critical temperature below which one observes deviation from the fluctuation-dissipation relation as consequence of the lack of equilibrium in the system.