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

Abstract

AbstractWe present an experimentally viable approach to demonstrate quantum non-locality in a matter-wave system via a Rarity–Tapster interferometer using two $$s$$ 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 $$V=0.42(9)$$ V = 0.42 ( 9 ) , corresponding to a maximum CSHS-Bell parameter of $$S=1.1(1)$$ S = 1.1 ( 1 ) , for the Clauser–Horne–Shimony–Holt (CHSH) version of the Bell inequality, between atoms separated by $$\sim 4$$ ∼ 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.