Dynamics in disordered systems

Abstract

In this work, we focus on hierarchical relaxation in complex systems. Two means of describing relaxation are considered in detail: first, we use a microscopic model based on continuous-time random walk (CTRW) ideas; this procedure is efficient in describing photoconductive behavior and is used here also in the framework of polymer chain dynamics, by letting each bead move according to its own waiting-time distribution. Second, a more qualitative picture for relaxation emerges from constitutive expressions with fractional derivatives: we present two mechanical realizations for a basic fractional differential equation.