Universality of jamming of nonspherical particles

• Published in: Proceedings of the National Academy of Sciences - PNAS 2018-11, Vol.115 (46), p.11736-11741
• Main Authors: Brito, Carolina, Ikeda, Harukuni, 池田晴國, Urbanic, Pierfrancesco, Wyart, Matthieu, Zamponi, Francesco
• Format: Article
• Language: English
• Subjects: Atoms & subatomic particles; Computer simulation; Condensed Matter; Ellipsoids; Exponents; Jamming; Mathematical models; Physical Sciences; Physics; Simulation; Stability criteria; Vibration analysis
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.1812457115

Amorphous packings of nonspherical particles such as ellipsoids and spherocylinders are known to be hypostatic: The number of mechanical contacts between particles is smaller than the number of degrees of freedom, thus violating Maxwell’s mechanical stability criterion. In this work, we propose a general theory of hypostatic amorphous packings and the associated jamming transition. First, we show that many systems fall into a same universality class. As an example, we explicitly map ellipsoids into a system of “breathing” particles. We show by using a marginal stability argument that in both cases jammed packings are hypostatic and that the critical exponents related to the contact number and the vibrational density of states are the same. Furthermore, we introduce a generalized perceptron model which can be solved analytically by the replica method. The analytical solution predicts critical exponents in the same hypostatic jamming universality class. Our analysis further reveals that the force and gap distributions of hypostatic jamming do not show power-law behavior, in marked contrast to the isostatic jamming of spherical particles. Finally, we confirm our theoretical predictions by numerical simulations.