May 10 2016
16-18.05.2016: Visit of Shamik Gupta
Shamik Gupta (Max Planck Institute for the Physics of Complex Systems, Dresden, Germany) is visiting us. On Tuesday 17.05.2016 at 9 am in room 4.18 he will give a talk on 'Long-range interacting systems driven out of equilibrium'.
Abstract: Systems with long-range interactions have an inter-particle
interaction potential that decays slower than 1/r^d in d dimensions.
Examples are widespread, from plasmas, dipolar ferroelectrics and
ferromagnets, to gravitational systems. After a brief introduction to
unusual static and dynamic properties of long-range systems, I will dwell
on the question: What happens when a long-range system is driven out of
thermal equilibrium by, e.g., an impulsive kick? In similar situations,
short-range systems would typically relax to another thermal equilibrium
with a uniform temperature across the system. By contrast, a long-range
system relaxes to non-Boltzmann nonequilibrium stationary states that
support a non-uniform temperature profile across the system. More striking
and counterintuitive is the observation of temperature inversion in such a
state: denser parts of the system are colder than dilute ones. Such
inversions occur in nature, e.g., in the solar corona and in interstellar
molecular clouds. We demonstrate how an interplay of wave-particle
interaction and spatial inhomogeneity offers a simple and appealing
mechanism to explain temperature inversion in generic long-range systems.