title: Entanglement test on a microscopic-macroscopic system.
abstract: A macrostate consisting of N approximately 3.5x10{4} photons in a quantum superposition and entangled with a far apart single-photon state (microstate) is generated. Precisely, an entangled photon pair is created by a nonlinear optical process; then one photon of the pair is injected into an optical parametric amplifier operating for any input polarization state, i.e., into a phase-covariant cloning machine. Such transformation establishes a connection between the single photon and the multiparticle fields. We then demonstrate the nonseparability of the bipartite system by adopting a local filtering technique within a positive operator valued measurement.
authors.affiliation: Dipartimento di Fisica dell'Universitá La Sapienza and Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia, Roma, 00185 Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: De Martini
authors.forename: Fabio
authors.initials: F
authors.lastname: Sciarrino
authors.forename: Chiara
authors.initials: C
authors.lastname: Vitelli