title: Complementarity and correlations.
abstract: We provide an interpretation of entanglement based on classical correlations between measurement outcomes of complementary properties: States that have correlations beyond a certain threshold are entangled. The reverse is not true, however. We also show that, surprisingly, all separable nonclassical states exhibit smaller correlations for complementary observables than some strictly classical states. We use mutual information as a measure of classical correlations, but we conjecture that the first result holds also for other measures (e.g., the Pearson correlation coefficient or the sum of conditional probabilities).
authors.affiliation: Dipartimento Fisica and INFN Sezione di Pavia, University of Pavia, via Bassi 6, I-27100 Pavia, Italy.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Maccone
authors.affiliation: Institut für Theoretische Physik III, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany.
authors.forename: Dagmar
authors.initials: D
authors.lastname: Bruß
authors.affiliation: Dipartimento Fisica and INFN Sezione di Pavia, University of Pavia, via Bassi 6, I-27100 Pavia, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Macchiavello