title: Nonclassicality Invariant of General Two-Mode Gaussian States.
abstract: We introduce a new quantity for describing nonclassicality of an arbitrary optical two-mode Gaussian state which remains invariant under any global photon-number preserving unitary transformation of the covariance matrix of the state. The invariant naturally splits into an entanglement monotone and local-nonclassicality quantifiers applied to the reduced states. This shows how entanglement can be converted into local squeezing and vice versa. Twin beams and their transformations at a beam splitter are analyzed as an example providing squeezed light. An extension of this approach to pure three-mode Gaussian states is given.
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: 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: Jiří
authors.initials: J
authors.lastname: Svozilík
authors.affiliation: Faculty of Physics, Adam Mickiewicz University, PL-61-614 Poznan, Poland.
authors.forename: Adam
authors.initials: A
authors.lastname: Miranowicz