The Memory of Sand

Complex systems are characterized by an abundance of meta-stable states. To describe such systems statistically, one must understand how states are sampled, a difficult task in general when thermal equilibrium does not apply. This problem arises in various fields of science, and here I will focus on a simple example, sand. Sand can flow until one jammed configuration (among the exponentially many possible ones) is reached. I will argue that these dynamically-accessible configurations are atypical, implying that in its solid phase sand "remembers" that it was flowing just before it jammed. As a consequence, it is stable, but barely so. I will argue that this marginal stability answers long-standing questions both on the solid and liquid phase of granular materials, and will discuss tentatively the applicability of this idea to other systems.

Faculty Host: Bob Behringer.

Refreshments will be provided after the event in room 128.

Event Date: 
Wednesday, April 9, 2014 - 3:30pm
Event Location: 
Physics 128
Event Contact: 
Paul, Cristin
Event Contact Email: 
Event Contact Phone: 
Event Speaker: 
Matthieu Wyart (NYU)