Spatio-Temporal Correlations in Coulomb Clusters

<strong>Seminar of the School of Physical Sciences</strong> <strong>--------------------------------------------------</strong> Title: <strong>Spatio-Temporal Correlations in Coulomb Clusters</strong> Speaker: <strong>Amit Ghosal</strong> (IISER Kolkata) Date:<strong> July 29, 2016 </strong> <strong>Abstract:</strong> Temperature dependent static and dynamic responses of Coulomb interacting particles in two-dimensional confinements will be discussed illustrating a thermal crossover in them. Using density correlations we probe intriguing signatures of an amorphous solid and an inhomogeneous liquid phases arising out of disorder and long-range interactions. The spatio-temporal relaxation occurs at multiple time scales and shows a stretched-Gaussian and stretched-exponential spatial decay at long times in circular and irregular traps respectively. Interplay of confinement and long-range interaction yields spatially correlated motion of particles, leaving the system heterogeneous up to a rather long time. While particles in a `solid' flow producing dynamic heterogeneities, their random motion in `liquid' defies central limit theorem. We devise several criteria to explore the crossover between these solid- and liquid-like phases. A phenomenological model, relating the unusual dynamics to the heterogeneous nature of the diffusivities in the system, captures much of the subtleties of our numerical simulations. Our results indicate that confined systems, specifically those with lower spatial symmetries, show some of the key signatures of supercooled liquids.