title: Structural and microscopic relaxations in a colloidal glass.
abstract: The aging dynamics of a colloidal glass has been studied by multiangle dynamic light scattering, neutron spin echo, X-ray photon correlation spectroscopy and molecular dynamics simulations. The two relaxation processes, microscopic (fast) and structural (slow), have been investigated in an unprecedentedly wide range of time and length scales covering both ergodic and nonergodic regimes. The microscopic relaxation time remains diffusive at all length scales across the glass transition scaling with wavevector Q as Q(-2). The length-scale dependence of structural relaxation time changes from diffusive, characterized by a Q(-2)-dependence in the early stages of aging, to a Q(-1)-dependence in the full aging regime which marks a discontinuous hopping dynamics. Both regimes are associated with a stretched behaviour of the correlation functions. We expect these findings to provide a general description of both relaxations across the glass transition.
authors.affiliation: Center for Life Nano Science, IIT@Sapienza, Istituto Italiano di Tecnologia, Viale Regina Elena 291, I-00161 Roma, Italy. flavio.marques@iit.it.
authors.forename: Flavio Augusto
authors.initials: FA
authors.lastname: de Melo Marques
authors.forename: Roberta
authors.initials: R
authors.lastname: Angelini
authors.forename: Emanuela
authors.initials: E
authors.lastname: Zaccarelli
authors.forename: Bela
authors.initials: B
authors.lastname: Farago
authors.forename: Beatrice
authors.initials: B
authors.lastname: Ruta
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Ruocco
authors.forename: Barbara
authors.initials: B
authors.lastname: Ruzicka