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Stress Relaxation above and below the Jamming Transition
Kuniyasu Saitoh1, Takahiro Hatano2, Atsushi Ikeda3,4
1Research Alliance Center for Mathematical Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.
Physical Review Letters
|April 4, 2020
Summary
Critical slowing down in soft matter systems near the jamming point shows different relaxation exponents when approached from jammed versus unjammed states. This anomaly is linked to an extra slow vibrational mode below jamming.
Area of Science:
- Soft matter physics
- Statistical mechanics
- Rheology
Background:
- Athermal systems exhibit jamming transitions, a critical point where disordered materials gain rigidity.
- Understanding stress relaxation dynamics near jamming is crucial for predicting material behavior.
Purpose of the Study:
- To numerically investigate stress relaxation in soft athermal disks near the jamming point.
- To identify and explain anomalous critical slowing down behavior.
Main Methods:
- Numerical simulations of soft athermal disks.
- Analysis of stress relaxation dynamics.
- Investigation of the vibrational density of states.
Main Results:
- Observed critical slowing down as systems approach the jamming point.
- Found distinct relaxation time exponents when approaching from the jammed and unjammed phases.
- Identified an extra slow vibrational mode emerging below jamming.
Conclusions:
- The divergence of relaxation time exponents near jamming is asymmetric, differing from conventional critical scaling.
- The vibrational density of states, particularly an emergent slow mode below jamming, explains this anomalous behavior.
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