title: Detection of entanglement with polarized photons: experimental realization of an entanglement witness.
abstract: We report on the first experimental realization of an entanglement witness, a method to detect entanglement with few local measurements. The present demonstration has been performed with polarized photons in Werner states, a well-known family of mixed states that can be either separable or nonseparable. The Werner states are generated by a novel high brilliance source of bipartite entangled states by which the state mixedness can be easily adjusted.
authors.affiliation: Dipartimento di Fisica and Istituto Nazionale per la Fisica della Materia, Università di Roma La Sapienza, 00185 Rome, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Barbieri
authors.forename: F
authors.initials: F
authors.lastname: De Martini
authors.forename: G
authors.initials: G
authors.lastname: Di Nepi
authors.forename: P
authors.initials: P
authors.lastname: Mataloni
authors.forename: G M
authors.initials: GM
authors.lastname: D'Ariano
authors.forename: C
authors.initials: C
authors.lastname: Macchiavello