Activated aging dynamics and negative fluctuation-dissipation ratios.
In glassy materials, aging proceeds at large times via thermal activation. We show that this can lead to negative dynamical response functions and novel and well-defined violations of the fluctuation-dissipation theorem, in particular, negative fluctuation-dissipation ratios. Our analysis is based on detailed theoretical and numerical results for the activated aging regime of simple kinetically constrained models. The results are relevant to a variety of physical situations, such as aging in glass formers, thermally activated domain growth, and granular compaction.
Department of Chemistry, Columbia University, 3000 Broadway, New York, New York 10027, USA.
Peter
P
Mayer
Sébastien
S
Léonard
Ludovic
L
Berthier
Juan P
JP
Garrahan
Peter
P
Sollich