title: Multiparticle quantum superposition and stimulated entanglement by parity selective amplification of entangled states.
abstract: We report the creation of an entangled multiphoton quantum superposition by quantum injection of entangled 2-photon states into a parity selective parametric amplifier. The information preserving property of the state transformation suggests for these macrostates the name of large qubits. They are ideal objects for investigating the emergence of the classical world in complex quantum systems and have relevant new applications in quantum information.
authors.affiliation: Dipartimento di Fisica and Istituto Nazionale di Fisica della Materia, Universitá "La Sapienza," Roma 00185, Italy.
authors.forename: F
authors.initials: F
authors.lastname: De Martini
authors.forename: G
authors.initials: G
authors.lastname: Di Giuseppe
authors.forename: S
authors.initials: S
authors.lastname: Pádua