title: How quantum correlations enhance prediction of complementary measurements.
abstract: If there are correlations between two qubits, then the results of the measurement on one of them can help to predict measurement results on the other one. It is an interesting question as to what can be predicted about the results of two complementary projective measurements on the first qubit. To quantify these predictions the complementary knowledge excesses are used. A nontrivial constraint restricting them is derived. For any mixed state and for arbitrary measurements the knowledge excesses are bounded by a factor depending only on the maximal violation of Bell's inequalities. This result is experimentally verified on two-photon Werner states prepared by means of spontaneous parametric down-conversion.
authors.affiliation: Department of Optics, Palacký University, 17. listopadu 50, 772 00 Olomouc, Czech Republic.
authors.forename: Radim
authors.initials: R
authors.lastname: Filip
authors.forename: Miroslav
authors.initials: M
authors.lastname: Gavenda
authors.forename: Jan
authors.initials: J
authors.lastname: Soubusta
authors.forename: Antonín
authors.initials: A
authors.lastname: Cernoch
authors.forename: Miloslav
authors.initials: M
authors.lastname: Dusek