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Effective temperature of an aging powder
1Laboratoire de Physique, Ecole Normale Supérieure de Lyon, 46 Allée d'Italie, 69007 Lyon, France.
Summary
This study explores powder compaction dynamics using a 3D model, revealing super-aging behavior and a novel dynamical temperature. An experiment is proposed to measure this effective temperature in aging systems.
Area of Science:
- Physics
- Materials Science
- Complex Systems
Background:
- Aging dynamics are crucial in materials science, particularly in granular systems and glasses.
- The fluctuation-dissipation relation connects system response to external forces and internal fluctuations.
- Understanding compaction in powders is essential for various industrial applications.
Purpose of the Study:
- To numerically investigate the aging dynamics in a 3D compacting powder model.
- To analyze the fluctuation-dissipation relation in the presence of noise and stirring forces.
- To characterize the effective temperature in the context of compaction and aging.
Main Methods:
- Numerical simulation of a 3D gravity-driven lattice-gas model.
- Application of purely kinetic constraints to model powder compaction.
- Analysis of spontaneous diffusion (noise) and drift motion (stirring force).
Main Results:
- Observed super-aging behavior in the compaction dynamics.
- Identified a purely dynamical, time-scale-dependent effective temperature, analogous to glasses.
- Established a fluctuation-dissipation relation for this system.
Conclusions:
- The 3D powder compaction model exhibits complex aging phenomena.
- A novel dynamical effective temperature can characterize the aging process.
- The findings suggest a new experimental approach to measure this dynamical temperature.