title: Entanglement and nonclassicality in four-mode Gaussian states generated via parametric down-conversion and frequency up-conversion.
abstract: Multipartite entanglement and nonclassicality of four-mode Gaussian states generated in two simultaneous nonlinear processes involving parametric down-conversion and frequency up-conversion are analyzed assuming the vacuum as the initial state. Suitable conditions for the generation of highly entangled states are found. Transfer of the entanglement from the down-converted modes into the up-converted ones is also suggested. The analysis of the whole set of states reveals that sub-shot-noise intensity correlations between the equally-populated down-converted modes, as well as the equally-populated up-converted modes, uniquely identify entangled states. They represent a powerful entanglement identifier also in other cases with arbitrarily populated modes.
authors.affiliation: RCPTM, Joint Laboratory of Optics of Palacký University and Institute of Physics of the Czech Academy of Sciences, 17. listopadu 12, 77146 Olomouc, Czech Republic.
authors.forename: Ievgen I
authors.initials: II
authors.lastname: Arkhipov
authors.affiliation: RCPTM, Joint Laboratory of Optics of Palacký University and Institute of Physics of the Czech Academy of Sciences, 17. listopadu 12, 77146 Olomouc, Czech Republic.
authors.forename: Jan
authors.initials: J
authors.lastname: Peřina
authors.affiliation: Institute of Physics of CAS, Joint Laboratory of Optics of Palacký University and Institute of Physics, 17. listopadu 50a, 771 46 Olomouc, Czech Republic.
authors.forename: Ondřej
authors.initials: O
authors.lastname: Haderka
authors.affiliation: Dipartimento di Scienza e Alta Tecnologia, Università degli Studi dell'Insubria, Via Valleggio 11, 22100 Como, Italy.
authors.forename: Alessia
authors.initials: A
authors.lastname: Allevi
authors.affiliation: Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche, Via Valleggio 11, 22100 Como, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Bondani