title: Homodyne estimation of Gaussian quantum discord.
abstract: We address the experimental estimation of Gaussian quantum discord for a two-mode squeezed thermal state, and demonstrate a measurement scheme based on a pair of homodyne detectors assisted by Bayesian analysis, which provides nearly optimal estimation for small value of discord. In addition, though homodyne detection is not optimal for Gaussian discord, the noise ratio to the ultimate quantum limit, as dictated by the quantum Cramer-Rao bound, is limited to about 10 dB.
authors.affiliation: Laboratoire Charles Fabry, Institut d'Optique, CNRS, Université Paris-Sud, Campus Polytechnique, RD 128, 91127 Palaiseau Cedex, France. remi.blandino@institutoptique.fr
authors.forename: Rémi
authors.initials: R
authors.lastname: Blandino
authors.forename: Marco G
authors.initials: MG
authors.lastname: Genoni
authors.forename: Jean
authors.initials: J
authors.lastname: Etesse
authors.forename: Marco
authors.initials: M
authors.lastname: Barbieri
authors.forename: Matteo G A
authors.initials: MG
authors.lastname: Paris
authors.forename: Philippe
authors.initials: P
authors.lastname: Grangier
authors.forename: Rosa
authors.initials: R
authors.lastname: Tualle-Brouri