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.