Quantum tests of the equivalence principle with atom interferometry

The weak equivalence principle (EP) represents a corner stone in the general theory of relativity [1]. The validity of this postulate was and is currently tested in different groups with different systems. Among this multitude of methods atom interferometry is considered to be one of the most promising tools in performing high-precision measurements [2]. Using two atom species in free fall with different masses allows comparing two independent measurements of g. This is made possible by creating a mixture of two atomic species at a temperature close to absolute zero. This regime is suitable for the observation of matter waves at long time scales needed for high-precision quantum tests. In this letter an overview of the developments of our quantum sensor devices is done. The up-to-date progress and future prospects in our group of these ambitious and technically challenging projects are briefly presented as well. (c) 2010 Elsevier Ltd. All rights reserved.