Cyclic Memories in Disordered Matter

Cyclic Memories in Disordered Matter
Nathan Keim, Pennsylvania State University, Department of Physics
Prof. Nathan Keim
Date and time: Thu, Feb 20, 2020 - 11:30am
Refreshments at 11:15am
Location: LGRT 1033
Category: Condensed Matter Seminar
Abstract:

Cyclic driving happens all around us. Buildings and bridges are repeatedly loaded and unloaded, and many organisms synchronize their functions with day and night. This kind of driving can change a material, and even form memories that can be recalled later. I present two examples of materials that, when deformed repeatedly, can "learn" and report the magnitudes of those deformations: a suspension of particles in liquid, and a jammed amorphous solid. These exemplify two different but generic ways that non-equilibrium systems can form memories, with suspensions sharing their behavior with charge-density wave conductors, and amorphous solids approximating the return-point behavior best known in magnetic materials. Memory formation offers a new perspective on these and other systems' non-equilibrium natures, and illuminates the benefits of disorder and noise.