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 Li-7 atoms. Directional atomic beams with vertical bar F = 1, m(F) = 1 > and vertical bar F = 1, m(F) = -1 > spin states are generated from vertical bar F = 1, m(F) = 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 (vertical bar F = 1, m(F) = +/- 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- and intraspin-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. Our Letter paves the way to generating macroscopic quantum entanglement with the spin and motional degree of freedom with massive particles. It has a wide range of applications from quantum information science to the fundamental studies of quantum entanglement.