College of Science and Mathematics
BS in Physics
Dr. Nathan Keim
Simulations have shown that in many solid materials, rearrangements within the solid obey power-law statistics. A connection has been proposed between these statistics and the ability of a system to reach a limit cycle under cyclic driving. We study experimentally a 2D jammed solid that reaches such a limit cycle. Our solid consists of microscopic plastic beads adsorbed at an oil-water interface and cyclically sheared by a magnetically driven needle. We track each particles trajectory in the solid to identify rearrangements. By associating particles both spatially and temporally, we can measure the extent of each rearrangement. We study specifically the effects of the driving amplitude and number of cycles on the statistics of rearrangement sizes. As the cycle number increases, the overall number of rearrangements decreases; as the driving amplitude increases, the overall number of rearrangements increases. Additionally, it appears that below the systems yielding transition different driving amplitudes result in similar power-law-like distributions. We will explore in future experiments whether the distribution changes as we approach the critical amplitude where limit cycles become impossible.
Available for download on Saturday, June 24, 2023