The motion of electrons and atomic nuclei on ultrafast time scales lies at the heart of many processes in physics, chemistry, and biology, from the interaction of matter with light to the transfer of energy and charge. We use analytical models and numerical simulations to understand these processes and ultimately learn how to control and engineer them. We also develop efficient computational methods for describing the ultrafast motion of interacting electrons. Our group is part of the Regensburg Center for Ultrafast Nanoscopy (RUN) (external link, opens in a new window).