Coarsening dynamics of umbilical defects in inhomogeneous medium

Abstract

Non-equilibrium systems with coexistence of equilibria exhibit a rich and complex defects dynamics in order to reach a more stable configuration. Nematic liquid crystals layer with negative dielectric constant and homeotropic anchoring under the influence of a voltage are the ideal context for studying the interaction of gas of topological vortices. The number of vortices decreases with time. Experimentally, we show that the presence of imperfections drastically changes this coarsening law. Imperfections are achieved by considering glass beads inside the nematic liquid crystal sample. Depending on the disorder of these imperfections, the system exhibits different statistical evolution of the number of umbilical defects. The coarsening dynamics is persistent and is characterized by power laws with different exponents.