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 predominately form string like structures, and the particle trajectories show a 1D correlated motion that follows the defect strings. At higher temperatures this heterogeneous motion is lost. We demonstrate this heterogeneity both in systems interacting with a short ranged screened Coulomb interaction, as well as in systems with a long range logarithmic interaction between the particles.
@article{arxiv.cond-mat/0209334,
title = {Fluctuating Topological Defects in 2D Liquids: Heterogeneous Motion and Noise},
author = {C. Reichhardt and C. J. Olson Reichhardt},
journal= {arXiv preprint arXiv:cond-mat/0209334},
year = {2009}
}