In our group we study the physics of ultra-cold atoms and quantum gases in zero gravity. Quantum optical experiments in zero gravity can extend the science of such degenerate quantum gases towards otherwise inaccessible regimes of lowest temperatures, at and possibly below the pico-Kelvin regime, macroscopic dimensions, and unequalled durations of unperturbed free evolution.
In particular, Bose Einstein Condensates (BECs) are of interest as a coherent source of matter waves for matter wave interferometry measurements in microgravity. Matter wave interferometers have been used in a variety of laboratory experiments already, e.g. precise measurements of inertial forces or fundamental constants such as the fine structure constant or Newton´s gravitational constant. The extended unperturbed free fall of ultra-cold atoms as test particles in a low-noise environment in principle allows for much improved matter wave interferometry measurements.
In the long run the experiments carried out at the drop tower serve as a pathfinder to evaluate the potential of such experiments on space based platforms and to advance the technology readiness for space based applications. Two different trapping and cooling technologies are currently pursued at the drop tower. The QUANTUS collaborative project applies trapping and cooling in a magnetic chip trap, whereas the PRIMUS project uses an optical dipole trap.
Several of our activities are dedicated to measuring gravitational forces and to testing the foundation of gravity theory. For example, one scientific objective of our quantum gas experiments (QUANTUS, PRIMUS) in the drop tower is to perform a free fall test of the Equivalence Principle, a corner stone of general relativity theory. Further efforts of our group are to test the gravitational redshift (RELAGAL project) or to devise further space based experiments to test for relativistic clock effects.