The Cluster of Excellence QUEST - Centre for Quantum Engineering and Space-Time Research has been funded since November 2007 in the framework of the German Universities Excellence Initiative of the federal and state governments of Germany. The key research areas of the cluster are the quantum engineering and the space-time research. The Cluster of Excellence is with scientists from the fields of quantum optics, laser physics, solid state physics, gravitational physics, theoretical physics and geodesy interdisciplinary orientated. Involved are institutes of Leibniz University Hannover and several partner institutions. Speaker of the Excellence Cluster is Wolfgang Ertmer, Deputy Spokesman is Karsten Danzmann.