Quantum Gases in Microgravity
Aims of the projects
Microgravity is expected to be a decisive condition for the next leap in tests of fundamental physics of gravity, relativity, and theories beyond the standard model. Promising techniques for fundamental tests in the quantum domain are matter-wave sensors based on cold atoms or atom lasers, which use atoms as unperturbed microscopic test bodies for measuring inertial forces or as frequency references.
Microgravity is of high relevance for matter-wave interferometers and experiments with quantum matter, like Bose-Einstein condensates or degenerate Fermi gases, as it permits the extension of the unperturbed free evolution of these test particles (wave packets) in a low-noise environment.
In the beginning of the QUANTUS project (QUANTen Gase Unter Schwerelosigkeit) in 2004 the Droptower in Bremen (ZARM) was chosen as the microgravity environment (see also Tom Scott at the Drop Tower Bremen), since it provides both good accessibility and a better quality of microgravity than other platforms. With the funding provided by the DLR (Deutsches Zentrum für Luft- und Raumfahrt) the apparatus QUANTUS-1 started as a feasibility study of a compact, robust and mobile experiment for the creation of a BEC in a weightlessness environment.
Due to the success of the QUANTUS-1 experiment, additional projects have been initiated to further investigate the potency of ultra-cold atoms in microgravity. QUANTUS-2 expedites the miniaturisation of the experimental setup and is testing new concepts of atom optics in microgravity, like magnetic lenses to collimate the matter-wave in three dimensions. This will dramatically enhance the quality of the input matter-wave for the following interferometric measurements. Beside the generation of a rubidium BEC, QUANTUS-2 will be upgraded next year to generate ultra-cold clouds of potassium and by this will in the future contribute to the test of the equivalence principle in the quantum domain by differential atom interferometric measurements.
Since 2010 the next decisive enterprise for matter-wave interferometers for extended microgravity operation has been started. To utilize a new challenging microgravity platform, a novel apparatus MAIUS-A was set up, being ruggedized and miniaturized to fit onto a sounding rocket, to bring matter-wave interferometry into space. These sounding rocket missions will provide a parabola flight, enabling durations of up to 6 minutes in space. The first sounding rocket mission MAIUS-1 will be launched end of 2016 and prepare the ground for upcomeing ultra-cold atoms in space.
For these projects, innovative new laser systems and electronics need to be developed. LASUS (Lasersysteme unter Schwerelosigkeit) is a project to drive the miniaturisation of these components to its limits, demonstrating their feasibility for experiments in microgravity.