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Universal Relaxation Dynamics of Sphere Packings below Jamming
Atsushi Ikeda1,2, Takeshi Kawasaki3, Ludovic Berthier4
1Graduate School of Arts and Sciences, University of Tokyo, Tokyo 153-8902, Japan.
Physical Review Letters
|February 22, 2020
Summary
Non-Brownian suspensions exhibit slow dynamics near jamming, with a timescale diverging at the jamming transition. This timescale is encoded in the packing structure and measurable via vibrational density of states.
Area of Science:
- Physics
- Soft Matter Physics
- Rheology
Background:
- Non-Brownian suspensions of repulsive spheres exhibit complex dynamics near the jamming transition.
- Understanding the relationship between structure and dynamics is crucial for predicting material behavior.
Purpose of the Study:
- To investigate the slow relaxational dynamics of non-Brownian suspensions below jamming.
- To determine if the characteristic timescale is encoded in the packing structure and measurable via vibrational density of states.
- To compare the dynamic critical exponent for randomly generated and sheared packings.
Main Methods:
- Analysis of non-Brownian suspensions of repulsive spheres.
- Measurement of characteristic timescale via vibrational density of states.
- Comparison of dynamic critical exponent for different packing generation methods.
Main Results:
- A slow relaxational dynamics was observed below jamming, with a characteristic timescale that diverges at jamming.
- The slow timescale is fully encoded in the structure of the unjammed packing.
- The dynamic critical exponent is the same for randomly generated and sheared packings.
- A unique diverging timescale with a universal critical exponent controls various physical situations.
Conclusions:
- The jamming transition in non-Brownian suspensions is characterized by a diverging timescale.
- Vibrational density of states provides a method to measure this critical timescale.
- The dynamic critical exponent is universal, independent of packing generation method.
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