title: Anomalous diffusion and response in branched systems: a simple analysis.
abstract: We revisit the diffusion properties and the mean drift induced by an external field of a random walk process in a class of branched structures, as the comb lattice and the linear chains of plaquettes. A simple treatment based on scaling arguments is able to predict the correct anomalous regime for different topologies. In addition, we show that even in the presence of anomalous diffusion, Einstein's relation still holds, implying a proportionality between the mean square displacement of the unperturbed systems and the drift induced by an external forcing.
authors.affiliation: Dipartimento di Fisica Università di Roma 'Sapienza', Piazzale Aldo Moro 2, I-00185 Roma, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Forte
authors.forename: Raffaella
authors.initials: R
authors.lastname: Burioni
authors.forename: Fabio
authors.initials: F
authors.lastname: Cecconi
authors.forename: Angelo
authors.initials: A
authors.lastname: Vulpiani