The fundamental research interest of our research group focuses on collective effects in dilute, strongly interacting systems of high phase space density: ultracold gases and plasmas, high-energy-density plasmas, and high-brightness electron and ion beams. Essential research aspects are the manipulation of matter with coherent light - laser-cooling and trapping, laser-assisted particle creation and acceleration - and the generation of coherent radiation. The objective is to achieve total control over such systems by tailoring the fundamental interactions. Quantum coherence is the ultimate goal, pursued in both fundamental research and applications. Applications are advanced particle beams and radiation sources for nanotechnology and the life sciences.