Fluctuating Topological Defects in 2D Liquids: Heterogeneous Motion and Noise

Abstract

We measure the defect density as a function of time at different temperatures in simulations of a two-dimensional system of interacting particles. Just above the solid to liquid transition temperature, the power spectrum of the defect fluctuations shows a $1/f$ signature, which crosses over to a white noise signature at higher temperatures. When $1/f$ noise is present, the 5–7 defects predominantly form stringlike structures, and the particle trajectories show a 1D correlated motion that follows the defect strings. At higher temperatures this heterogeneous motion is lost.