Logarithmic Relaxations in a Random Field Lattice Gas Subject to Gravity

TL;DR

This paper introduces a lattice gas model with random fields and gravity to study slow, logarithmic relaxation and aging effects in disordered granular systems, highlighting universal features in off-equilibrium dynamics.

Contribution

The study presents a simple lattice gas model incorporating gravity and disorder to analyze slow relaxation and aging, revealing universal features in off-equilibrium dynamics.

Findings

Bulk density relaxes logarithmically over time.

Aging effects are observed in two-time correlation functions.

Universal features are identified in relaxation processes across similar models.

Abstract

A simple lattice gas model with random fields and gravity is introduced to describe a system of grains moving in a disordered environment. Off equilibrium relaxations of bulk density and its two time correlation functions are numerically found to show logarithmic time dependences and "aging" effects. Similitudes with dry granular media are stressed. The connections with off equilibrium dynamics in others kinds of "frustrated" lattice models in presence of a directional driving force (gravity) are discussed to single out the appearance of universal features in the relaxation process.