Einstein-Podolsky-Rosen paradox observed in many-particle system for the first time


By directly measuring the spin correlations between spatially separated parts of a spin-squeezed Bose-Einstein condensate we observe entanglement that is strong enough for Einstein-Podolsky-Rosen steering: We can predict measurement outcomes for noncommuting observables in one spatial region on the basis of corresponding measurements in another region with an inferred uncertainty product below the Heisenberg uncertainty bound. This method could be exploited for entanglement-enhanced imaging of electromagnetic field distributions and quantum information tasks. The results were reported in Science 360, 409-413.