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Interaction-free measurements with ultracold atoms

Interaction-free measurements with ultracold atoms

An interaction-free measurement allows for the detection of a classical object - seemingly without any interaction with it. In a recent publication, we demonstrate that this concept can be implemented with ultracold atoms by utilizing the Quantum Zeno Effect in a Bose-Einstein condensate.

In our experiments, we employ an ultracold gas in an unstable spin configuration, which can undergo a rapid decay. The object—realized by a laser beam—prevents this decay because of the Quantum Zeno Effect and thus, its presence can be detected without interacting with a single atom. Contrary to existing proposals, our IFM does not require single-particle sources and is only weakly affected by losses and decoherence. We demonstrate confidence levels of 90%, well beyond previous optical experiments.

Nature Communications