Group seminar at MPQ and Zoom: Matter-Wave Lensing for Very Long Baseline Atom Interferometry

Dorothee Tell, IQO Hannover, Germany
Group seminar at MPQ lecture hall and Zoom
Tuesday, May 21, 09:00am (MEZ)

Experiments with quantum objects in gravitational fields probe the interface between the theories of quantum mechanics and general relativity. The method of light-pulse atom interferometry, where well-defined light pulses probe ensembles of ultracold atoms in free fall, is one way to realize such experiments. Since the measurement sensitivity depends on the free fall time of the atoms within the interferometer, terrestrial experiments aim for longer free fall baselines. In the Very Long Baseline Atom Interferometry (VLBAI) facility in Hannover atoms are launched from the bottom source chamber into a 10.5 m long vacuum tube, allowing for a total interferometry time of 2.55 s. Performing precision experiments in such a device requires a high level of understanding of all systematic effects, like gravity and magnetic field gradients along the baseline, inhomogeneity in the interferometry light pulses, and the spatial expansion of the ensemble of atoms. This talk will discuss the arrangements made to build such a high-level precision experiment. It will focus on methods to reduce the three-dimensional expansion velocities of the ultracold atomic source using matter-wave lenses created by a time-averaged optical dipole trap.