Tuesday, October 1, 2013
Chemical Physics Seminar
High-dimensional Surprises Near the Glass and the Jamming Transitions
Patrick Charbonneau, Assistant Professor of Chemistry, Physics and CBB Program , Chemistry and Physics, Duke University
Abstract: The glass problem is notoriously hard and controversial. Even at the mean-field level, there is little agreement about how a fluid turns sluggish while exhibiting but unremarkable structural changes. It is clear, however, that the process involves self-caging, which provides an order parameter for the transition. It is also broadly assumed that this cage should have a Gaussian shape in the mean-field limit. Here we show that this ansatz does not generally hold when increasing the dimension of space, and explore some its materials consequences. We notably examine the complex relationship between non-Gaussian caging, dynamical fluctuations, and dimensionality in the breakdown of the Stokes-Einstein relation near the glass transition. Non-Gaussian caging also persists in the jamming limit of infinitely compressed hard spheres, which affects the mechanical stability of these packings. The dimensional perspective thus establishes clear mileposts for the emergence of a complete mean-field description of the glass and the jamming transitions.