On the definition of temperature in dense granular media
Abstract
In this Letter we report the measurement of a pseudo-temperature for compacting granular media on the basis of the Fluctuation-Dissipation relations in the aging dynamics of a model system. From the violation of the Fluctuation-Dissipation Theorem an effective temperature emerges (a dynamical temperature T_{dyn}) whose ratio with the equilibrium temperature T_d^{eq} depends on the particle density. We compare the results for the Fluctuation-Dissipation Ratio (FDR) T_{dyn}/T_d^{eq} at several densities with the outcomes of Edwards' approach at the corresponding densities. It turns out that the FDR and the so-called Edwards' ratio coincide at several densities (very different ages of the system), opening in this way the door to experimental checks as well as theoretical constructions.
Cite
@article{arxiv.cond-mat/0111458,
title = {On the definition of temperature in dense granular media},
author = {Vittoria Colizza and Alain Barrat and Vittorio Loreto},
journal= {arXiv preprint arXiv:cond-mat/0111458},
year = {2009}
}
Comments
RevTex4 4 pages, 4 eps figures