Two-particle, four-mode interferometer for atoms

Pierre I Dussarrat (1) , Maxime I Perrier (1) , Almazbek I Imanaliev (2) , Raphael Lopes (3) , Alain Aspect (1) , Marc Cheneau (1) , Denis Boiron (1) , Christoph I Westbrook (1)

1 Laboratoire Charles Fabry / Optique atomique
2 LNE - SYRTE - Laboratoire national de métrologie et d'essais - Systèmes de Référence Temps-Espace
3 Cavendish Laboratory

We present a free-space interferometer to observe two-particle interference of a pair of atoms with entangled momenta. The source of atom pairs is a Bose-Einstein condensate subject to a dynamical instability, and the interferometer is realized using Bragg diffraction on optical lattices, in the spirit of our recent Hong-Ou-Mandel experiment. We report on an observation ruling out the possibility of a purely mixed state at the input of the interferometer. We explain how our current setup can be extended to enable a test of a Bell inequality on momentum observables.

Domains: Quantum Physics [quant-ph]; Quantum Gases [cond-mat.quant-gas]

Pierre I Dussarrat, Maxime I Perrier, Almazbek I Imanaliev, Raphael Lopes, Alain Aspect, et al.. Two-particle, four-mode interferometer for atoms. Physical Review Letters, 2017, 119, pp.173202. ⟨10.1103/PhysRevLett.119.173202⟩. ⟨hal-01551704v2⟩