Generalized Einstein Relation in an aging colloidal glass

Bérengère Abou (1) , François Gallet (1) , Pascal Monceau (1) , Noëlle Pottier (1)

1 MSC - Matière et Systèmes Complexes

We present an experimental and theoretical investigation of the Generalized Einstein Relation (GER), a particular form of a fluctuation-dissipation relation, in an out-of-equilibrium visco-elastic fluid. Micrometer beads, used as thermometers, are immersed in an aging colloidal glass to provide both fluctuation and dissipation measurements. The deviations from the Generalized Einstein Relation are derived as a function of frequency and aging time. The observed deviations from GER are interpreted as directly related to the change in the glass relaxation times with aging time. In our scenario, deviations are observed in the regime where the observation time scale is of the order of a characteristic relaxation time of the glass.

Mots clés: matériaux vitreux; relations fluctuation-dissipation

Domaines: Matière Molle [cond-mat.soft]

Bérengère Abou, François Gallet, Pascal Monceau, Noëlle Pottier. Generalized Einstein Relation in an aging colloidal glass. Physica A: Statistical Mechanics and its Applications, 2008, 387 (14), pp.3410-3422. ⟨10.1016/j.physa.2008.02.034⟩. ⟨hal-00023745v3⟩