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New jamming scenario: from marginal jamming to deep jamming.
Cang Zhao1, Kaiwen Tian, Ning Xu
1Department of Physics, University of Science and Technology of China, Hefei 230026, People's Republic of China.
Physical Review Letters
|April 27, 2011
Summary
We identified a crossover volume fraction in frictionless sphere packings, distinguishing deeply jammed solids from marginally jammed ones. Deeply jammed solids exhibit unique properties and structural changes, suggesting a new class of amorphous solids.
Area of Science:
- Physics of granular materials
- Condensed matter physics
- Statistical mechanics
Background:
- Jammed packings of frictionless spheres are fundamental models in condensed matter physics.
- Understanding the transition between different states of matter, like solids, is crucial.
- Previous studies focused on marginally jammed solids, leaving deeply jammed states less explored.
Purpose of the Study:
- To investigate the properties of jammed packings of frictionless spheres across a broad spectrum of volume fractions.
- To identify and characterize the crossover phenomenon separating distinct jamming regimes.
- To explore the unique structural and vibrational properties of deeply jammed solids.
Main Methods:
- Systematic simulation of frictionless sphere packings.
- Analysis of pair distribution functions to probe structure.
- Calculation of normal modes of vibration to study dynamics.
- Varying volume fractions to observe transitions.
Main Results:
- A distinct crossover volume fraction was identified, separating marginally and deeply jammed solids.
- Deeply jammed solids display scaling laws and exponents different from marginally jammed ones.
- Structural changes in pair distribution functions correlate with the jamming crossover.
- Anomalies in vibrational normal modes, including quasilocalization and altered low-frequency density of states, were observed in deeply jammed solids.
Conclusions:
- Deeply jammed systems represent a distinct class of amorphous solids.
- The identified crossover has significant implications for understanding the behavior of granular materials.
- Further research into these new amorphous solids is warranted.
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