Stefan Kehrein
REAL TIME DYNAMICS OF CORRELATED SYSTEMS OUT OF
EQUILIBRIUM
The behavior of
correlated systems driven far from equilibrium poses many interesting
questions. In this talk I will introduce a new theoretical approach for
investigating the real time dynamics of such systems. This approach
is reminiscent of canonical perturbation theory in classical
mechanics and shares many of its advantages, in particular it
resums the perturbation expansion such as to avoid secular terms in
time. I will then apply this approach to a Fermi gas where an
interaction is suddenly switched on at time t=0, i.e. the opposite of Landau's
adiabatic switching on. One finds a well-defined time regime with a
quasi-steady state resembling an interacting Fermi liquid at zero
temperature, which then thermalizes for larger times. This behavior is
generic and independent of the type of interaction.