Condensed Matter Seminar, Andrea Liu, U. Penn, "Jamming: A tale of two rigidities"

Mon, Nov 21, 2016, 1:15 pm to 2:15 pm
PCTS Seminar Room
When we first learn the physics of solids, we are taught the theory of perfect crystals. Only later do we learn that in the real world, all solids are imperfect. The perfect crystal is invaluable because we can describe real solids by perturbing around this extreme limit by adding defects. But such an approach fails to describe a glass, another ubiquitous form of rigid matter. I will argue that the jammed solid is an extreme limit that is the anticrystal--an opposite pole to perfect order. Like the perfect crystal, it is an abstraction that can be understood in depth and used as a starting point for understanding the mechanical properties of solids with surprisingly high amounts of order. Unlike the crystal, however, the jammed state becomes rigid via a critical phase transition, which can be described by a critical scaling ansatz, paving the way for a renormalization group analysis.