2017/08/08 by Philipp Kunkel, Maximilian Prüfer, Helmut Strobel +5 · 227 citations
Computer Science · Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #EPR paradox #Entanglement witness #Multipartite #Multipartite entanglement #Physics #Quantum #Quantum Information and Cryptography #Quantum entanglement #Quantum mechanics #Quantum network #Quantum optics and atomic interactions #Quantum sensor #Spin (aerodynamics) #Squashed entanglement #W state #cond-mat.quant-gas #quant-ph
paper · pdf · doi:10.1126/science.aao2254
published in Science 360(6387), 413-416 (American Association for the Advancement of Science) · 27 pages, 4 figures, 6 supplementary figures
arxiv created 2017/08/08 · openalex publication_date 2018/04/26 · arxiv updated 2018/05/04 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
A key resource for distributed quantum-enhanced protocols is entanglement between spatially separated modes. However, the robust generation and detection of entanglement between spatially separated regions of an ultracold atomic system remain a challenge. We used spin mixing in a tightly confined Bose-Einstein condensate to generate an entangled state of indistinguishable particles in a single spatial mode. We show experimentally that this entanglement can be spatially distributed by self-similar expansion of the atomic cloud. We used spatially resolved spin read-out to reveal a particularly strong form of quantum correlations known as Einstein-Podolsky-Rosen (EPR) steering between distinct parts of the expanded cloud. Based on the strength of EPR steering, we constructed a witness, which confirmed genuine 5-partite entanglement.