3:30–4:30 pm Maria Goeppert-Mayer Lecture Hall
Disorder is different
Sidney Nagel, University of Chicago
In a perfect crystal, every atom has its place in a unit cell that is repeated interminably throughout space. Amorphous solids have no such regularity or long-range order. It may not be surprising that disorder, by relaxing constraints, can lead to new principles for how matter can be assembled with distinctive properties.
We customarily start our study of disordered solids by considering perturbations about a crystal. This approach becomes increasingly untenable as the degree of disorder increases; it is abysmal for understanding the rigidity or excitations in a completely amorphous solid. Jamming is an alternate, far-from-equilibrium way of creating amorphous rigid solids that are qualitatively different from crystals. In jammed solids, a new principle emerges independence of bond-level response. By embracing disorder and embracing the aging of disordered materials, one can drive the overall system to different regimes of behavior and achieve unique, varied, textured, and tunable response.