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Markus Arndt
University of Vienna, AT

What quantum-interference assisted molecule metrology can tell us about reality and non-locality

Quantum physics stands for a series of dualities which have not yet been successfully cast into a universally accepted interpretation, since any one of them violates at least one principle of classical physics, such as our common notions of reality or locality. Single-molecule interferometry shows this dilemma in a particularly striking way, when it leads the eye of the observer to believe in the reality of composite particles, while at the same time showing that non-local information must exist. I will present recent experiments on advanced molecule metrology, that strongly suggest that molecular properties can be assigned a well-defined ontological meaning, even when the information about these properties seems to be available in regions of space-time that a point particle would never be able to explore. In that sense, matter-wave physics allows us to see the reality ‘inside’ of molecules even without observing these objects in the sense of ‘knowing where they are’. Matter-wave interferometry seduces us to think in terms of Bohmian mechanics, like only few other experiments would do. However, it also cautions us that the world is more complex than we currently grasp in a single picture.