Stephan De Bièvre (Univ. Lille)
Diffusion, linear friction and Ohmic transport in a Hamiltonian open
system.
Joint work with P. Lafitte, P. Parris and A. Silvius.
I will report on analytical and numerical work on a Hamiltonian
model of a particle moving
through a one-dimensional periodic medium
with which it exchanges momentum
and energy. The medium is modeled with
local harmonic degrees of freedom
and can be thought of as either a
periodic inelastic Lorentz gas or
as a classical version of the Holstein
polaron model. At positive
temperatures the particle executes a
diffusive motion in absence of a
driving field and exhibits Ohmic
behaviour when such a field is
present. We exhibit an
adiabatic-nonadiabatic transition
as a function of the temperature in
the behaviour of the system, with two different power law
dependences of the
diffusion constant at high and
low temperatures. I will discuss the
validity of the Kubo relation in
this context.