Journal of Modern Optics
Partial reconstruction of the motional Wigner function of an ensemble of helium atoms
Tilman Pfau, Christian Kurtsiefer
Abstract
We report on double-slit interference of the matter waves of metastable helium atoms in the intermediate regime between Fresnel and Fraunhofer diffraction. From these diffraction data, we partially reconstruct the Wigner function of the atomic motional state immediately behind the double slit by the inverse Radon transformation technique. We were able to observe negative parts of the Wigner function, making evident the quantum nature of the atomic centre-of-mass motion.