title: Entanglement's benefit survives an entanglement-breaking channel.
abstract: Entanglement is essential to many quantum information applications, but it is easily destroyed by quantum decoherence arising from interaction with the environment. We report the first experimental demonstration of an entanglement-based protocol that is resilient to loss and noise which destroy entanglement. Specifically, despite channel noise 8.3 dB beyond the threshold for entanglement breaking, eavesdropping-immune communication is achieved between Alice and Bob when an entangled source is used, but no such immunity is obtainable when their source is classical. The results prove that entanglement can be utilized beneficially in lossy and noisy situations, i.e., in practical scenarios.
authors.affiliation: Research Laboratory of Electronics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA. zszhang@mit.edu
authors.forename: Zheshen
authors.initials: Z
authors.lastname: Zhang
authors.forename: Maria
authors.initials: M
authors.lastname: Tengner
authors.forename: Tian
authors.initials: T
authors.lastname: Zhong
authors.forename: Franco N C
authors.initials: FN
authors.lastname: Wong
authors.forename: Jeffrey H
authors.initials: JH
authors.lastname: Shapiro