%0 Journal Article %T Interaction-Free Measurements, Atom Localisation and Complementarity %A Anders Karlsson %A Gunnar Bjork %A Erik Forsberg %J Physics %D 1997 %I arXiv %X We analyse interaction-free measurements on classical and quantum objects. We show the transition from a classical interaction free measurement to a quantum non-demolition measurement of atom number, and discuss the mechanism of the enforcement of complementarity in atom interferometric interaction-free measurements. %U http://arxiv.org/abs/quant-ph/9705006v1