A matter-wave Rarity-Tapster interferometer to demonstrate non-locality

We present an experimentally viable approach to demonstrate quantum non-locality in a matter-wave system via a Rarity-Tapster interferometer using two s-wave scattering halos generated by colliding helium Bose-Einstein condensates. The theoretical basis for this method is discussed, and its suitability is experimentally quantified. As a proof of concept, we demonstrate an interferometric visibility of V = 0.42(9), corresponding to a maximum CSHS-Bell parameter of S = 1.1(1), for the Clauser-Horne-Shimony- Holt (CHSH) version of the Bell inequality, between atoms separated by similar to 4 correlation lengths. This constitutes a significant step toward a demonstration of a Bell inequality violation for motional degrees of freedom of massive particles and possible measurements of quantum effects in a gravitationally sensitive system.

Automated summary

We present an experimentally viable approach to demonstrate quantum non-locality in a matter-wave system using a Rarity-Tapster interferometer. The suitability of this method is quantified through theoretical discussion and experimental results. As a proof of concept, we demonstrate an interferometric visibility and Bell parameter between atoms separated by a certain distance, which is important for studying motion degrees of freedom and quantum effects in a gravitationally sensitive system.