A jamming plane of sphere packings.

Area of Science:

• Physics of soft-matter, granular materials, and complex systems.
• Statistical mechanics and phase transitions.
• Computational physics and materials science.

Background:

• Jamming is a critical phenomenon relevant to liquids, glasses, colloids, foams, and granular materials.
• Existing models often focus on a single jamming point at a fixed density.
• Jamming is closely related to sphere packing and optimization problems.

Purpose of the Study:

• To extend the understanding of amorphous jammed states beyond the traditional jamming point.
• To investigate the role of density and shear strain in jamming phenomena.
• To explore the relationship between jamming, glass basins, and packing configurations.

Main Methods:

• Utilized athermal and thermal simulations for compression and shear jamming.
• Employed an efficient swap algorithm to prepare initial equilibrium configurations.
• Analyzed the reversibility of jamming routes to classify jamming regimes.

Main Results:

• Introduced the concept of a jamming-plane spanning density and shear strain axes for frictionless spheres.
• Divided the jamming-plane into reversible and irreversible jamming regimes.
• Demonstrated that all jammed states are isostatic and exhibit universal jamming criticality, with contact network anisotropy depending on density and strain.

Conclusions:

• The jamming-plane provides a more comprehensive framework for understanding jamming in soft matter.
• Irreversible jamming is linked to escaping metastable glass basins or their absence.
• The jamming-point represents a unique state with minimum density and maximum randomness; crystalline packings exhibit a shear jamming-line.