Dynamical response functions in models of vibrated granular media

TL;DR

This paper investigates the dynamical response of schematic lattice gas models of vibrated granular media to small perturbations, revealing off-equilibrium features and proposing a generalized fluctuation-dissipation relation, with connections to glassy systems and Edwards' compactivity.

Contribution

It introduces a generalized fluctuation-dissipation theorem for vibrated granular media models and explores their off-equilibrium dynamics and thermodynamic analogies.

Findings

Identification of off-equilibrium features in response functions

Proposal of a generalized fluctuation-dissipation relation

Discussion of links to glassy systems and Edwards' theory

Abstract

In recently introduced schematic lattice gas models for vibrated dry granular media, we study the dynamical response of the system to small perturbations of shaking amplitudes and its relations with the characteristic fluctuations. Strong off equilibrium features appear and a generalized version of the fluctuation dissipation theorem is introduced. The relations with thermal glassy systems and the role of Edwards' compactivity are discussed.