Special Seminar: Spatial entanglement patterns and Einstein-Podolsky-Rosen steering in a Bose-Einstein condensate

Dr. Matteo Fadel, PhD and postdoc work in Basel, Visiting the theory division

Atomic Bose-Einstein condensates (BECs) are highly controllable isolated quantum systems with long coherence times, and offer applications in metrology and quantum information processing. We experimentally prepare two-component Rubidium-87 BECs, consisting of a few hundred atoms, on an atom-chip. Using state-selective potentials to tune the collisional interactions (one-axis twisting dynamics), we prepare many-particle non-classical states. After a time-of-flight expansion, high-resolution images allows us to access sub-regions of the atomic density distribution of various shapes and measure the spin correlations between them.

We observe that bi-partitions violate a separability criterion, indicating the presence of entanglement between different spatial regions of our many-body system. In one of such partitions, entanglement is strong enough for Einstein-Podolsky-Rosen steering: measurement outcomes for non-commuting observables in one spatial region can be predicted based on a corresponding measurement in the other region with an inferred uncertainty product below the Heisenberg relation. This feature could be exploited for imaging of electromagnetic and other field distributions with an uncertainty beyond the standard quantum limit. 

Reference: http://science.sciencemag.org/content/360/6387/409