Entanglement swap now yields the same state every time

Mir Alimuddin, Jaemin Kim, Antonio Acín, and Leonardo Zambrano have published research detailing a new method for deterministic entanglement distribution in Quantum Science and Technology. The researchers characterized projective swapping measurements using full-Schmidt-rank vectors, achieving a consistent end-to-end state regardless of measurement outcome, up to local-unitary corrections. This work eliminates outcome-based postselection in entanglement swapping, a key primitive for building quantum networks. The results show these schemes retain every outcome while achieving optimal G-concurrence for pure inputs. This advance focuses on characterizing projective swapping measurements using vectors possessing full Schmidt rank, achieving consistent results across various input states. Researchers from ICFO, Institut de Ciencies Fotoniques, alongside collaborators from Aalborg University and KAIST, demonstrated that universally LU-deterministic measurements, those yielding…