We have recently proposed a very long baseline atom interferometer test of the universality of free fall. In the envisaged experiment, ultracold ensembles of rubidium and ytterbium will be dropped over a vertical free fall distance of 10m and undergo Mach-Zehnder-type atom interferometer geometries. In a first stage, an accuracy in the Eötvös ratio of 7x10-13 will be achieved. We treat the technical realization in the new infrastructure of the Hanover Institute of Technology (HITec) and discuss requirements on the apparatus needed to reach the projected uncertainty.
Our work is published in New J. Phys. 17, 035011 (2015) and was covered in "Balls and feathers".
