报告人：金瑜亮（中国科学院理论物理研究所）

报告时间：2020年5月20日下午14:00-15:00

腾讯会议ID：325902073

报告摘要：

The concept of jamming has attracted great research interest due to its broad relevance in soft- matter such as liquids, glasses, colloids, foams, and granular materials, and its deep connection to the sphere packing problem and optimization problems. Here we show that the domain of amorphous jammed states of frictionless spheres can be significantly extended, from the well-known jamming-point at a fixed density, to a jamming-plane that spans the density and shear strain axes. We explore the jamming-plane, via athermal and thermal simulations of compression and shear jamming, with a help of an efficient swap algorithm to prepare initial equilibrium configurations. The jamming-plane can be divided into reversible-jamming and irreversible-jamming regimes, based on the reversibility of the route from the initial configuration to jamming. Our results suggest that the irreversible-jamming behavior reflects an escape from the meta-stable glass basin to which the initial configuration belongs to, or the absence of such basins. All jammed states, either compression or shear jammed, are isostatic, and exhibit jamming criticality of the same universality class. However, the anisotropy of contact networks non-trivially depends on the jamming density and strain. Among all state points on the jamming-plane, the jamming-point is a unique one with the minimum jamming density and the maximum randomness. For lattice packings, the jamming-plane shrinks into a single shear jamming-line that is independent of initial configurations. Our study paves the way for solving the long-standing random close packing problem, and provides a more complete framework to understand jamming.

报告人简历 

金瑜亮博士2006年本科毕业于复旦大学， 并获得李政道先生的mini-CUSPEA（中美联合培养物理类研究生计划）奖学金支持赴美国留学。先后在美国、意大利、法国和日本有共计12年海外学习和研究的经历。2012年于美国纽约城市大学获得物理学博士学位。之后，在美国杜克大学、意大利罗马大学、法国高等师范学校进行博士后研究工作。2015年 至2018年，在日本大阪大学Cybermedia中心就职特任研究员。2018年4月起受聘为中国科学院理论物理研究所副研究员。主要研究领域为软凝聚态物理和非平衡态统计物理。近年来的主要研究课题包括非晶态物质中的玻璃相变、Gardner相变和jamming相变等。其研究成果在Science Advances, Nature Communications， PNAS等国际期刊上发表共20余篇。