Seminario
"Einstein relation for anomalous superdiffusive dynamics"
Relatore: Giacomo Gradenigo CNR  Istituto dei Sistemi Complessi  Roma
Aula Feynman
17 Aprile 2012 ore 16.30
Abstract

The relation of the mean square displacement of a particle suspended in an equilibrium fluid with its drift, when it is pulled by a constant force, was first discussed by Einstein, and represents the simplest example of FluctuationDissipation relation. We show here that, in the case of a collisional model with superdiffusive dynamics, the mean square displacement of the probe particle around its average
position behaves differently when studied in presence, or not, of a constant drag, yielding, in the former case, a breakdown of the so called Einstein relation. We discuss how such a breakdown depends on the degree of anomaly of the
dynamics, i.e. on the fat tails of the flight time distribution, and on the way of applying the external drag field.


