Speaker
Angelo Vulpiani
(Università di Roma "La Sapienza")
Description
As first we discuss as the Fluctuation Dissipation
Relations (FDRs) hold in a generalized form for
any systems with a stationary probability distribution.
One can say that the essence of the FDRs is the
possibility to establish a bridge between
equilibrium and non equilibrium properties.
We show how FDRs are useful tools to understand
the statistical behaviour of complex systems
such as driven granular gases and protein models.
In the first case although the velocity response function
of a particle and its velocity self-correlation are not
proportional, a generalized form of fluctuation-dissipation
relation holds, this is due to the presence of strong
correlations between velocities and spatial density.
This happens at high densities and strong inelasticities,
but still in the fluid-like (and ergodic) regime.
In addition we discuss how, following the Jarzynski- like
approach, i.e. perfoming a series of "pulling experiments",
one can infer the basic feature of the underlying dynamics.
(Joint work with F. Cecconi, A. Puglisi and D. Villamaina)
