Emission of Spin-correlated Matter-wave Jets from Spinor Bose-Einstein Condensates
Abstract
We report the observation of matter-wave jet emission in a strongly ferromagnetic spinor Bose-Einstein condensate of 7Li atoms. Directional atomic beams with |F=1,mF=1 and |F=1,mF=-1 spin states are generated from |F=1,mF=0 state condensates, or vice versa. This results from collective spin-mixing scattering events, where spontaneously produced pairs of atoms with opposite momentum facilitates additional spin-mixing collisions as they pass through the condensates. The matter-wave jets of different spin states (|F=1,mF=1) can be a macroscopic Einstein-Podolsky-Rosen state with spacelike separation. Its spin-momentum correlations are studied by using the angular correlation function for each spin state. Rotating the spin axis, the inter-spin and intra-spin momentum correlation peaks display a high contrast oscillation, indicating collective coherence of the atomic ensembles. We provide numerical calculations that describe the experimental results at a quantitative level and can identify its entanglement after 100~ms of a long time-of-flight.