Dynamics and control of of complex quantum systems out of equilibrium

Martin Eckstein

Ultrashort laser pulses allow to probe collective dynamical processes in complex solids on the intrinsic timescale of the microscopic degrees of freedom, starting from the electron dynamics on the timescale of femtoseconds. Moreover, with sufficiently strong pulses one can possibly steer solids into so-called hidden phases, which are not accessible along thermodynamic pathways, or dynamically stabilise such phases. In my lecture, I will give an overview on possible pathways to control condensed matter out of equilibrium. In particular, this includes (i), photo-doping, i.e. a modification of the electronic structure upon a laser-induced redistribution of electrons between different bands, and (ii), Floquet engineering, i.e., the laser control of the electronic structure and microscopic interactions in the solid through time-periodic perturbations. I will also give a brief overview over theoretical approaches to describe the electronic structure of solids out of equilibrium.