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Updated: Jun 28, 2026

An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
Published on: December 4, 2017
Definition of temperature in dense granular media
Vittoria Colizza1, Alain Barrat, Vittorio Loreto
1Università degli Studi di Roma La Sapienza, Dipartimento di Fisica, Piazzale Aldo Moro 5, 00185 Rome, Italy.
Abstract:
In this paper we report the measurement of a pseudotemperature 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 emerges an effective temperature (a dynamical temperature T(dyn)) whose value depends on the particle density. We compare the results for T(dyn) at several densities with the values of Edwards' compactivity at the corresponding densities [S. F. Edwards, in Granular Matter: An Interdisciplinary Approach, edited by A. Mehta (Springer-Verlag, New York, 1994) and references therein]. It turns out that the dynamical temperature and Edwards' compactivity coincide on a large range of densities, opening in this way the door to experimental checks as well as theoretical constructions.
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