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. Similarities with dry granular media are stressed. The connections with off-equilibrium dynamics in other kinds of "frustrated" lattice models in the presence of a directional driving force (gravity) are discussed to single out the appearance of universal features in the relaxation process. [References: 25]
展开▼
