Aging of a colloidal “Wigner” glass

We study the aging of a colloidal glass, which is obtained for extremely low volume fractions due to strong electrostatic repulsions, leading to the formation of a “Wigner glass”. During the aging, a new crossover between a complete and incomplete decay of the correlation function is observed, accompanied by an increase in the non-ergodicity parameter. The dynamics can be described as a cage-diffusion process. For short times, the escape of the particles from “cages” formed by neighbouring particles dominates; for long times the particles cannot escape anymore and the system becomes strongly non-ergodic.