title: Experimental generation of quantum discord via noisy processes.
abstract: Quantum systems in mixed states can be unentangled and yet still nonclassically correlated. These correlations can be quantified by the quantum discord and might provide a resource for quantum information processing tasks. By precisely controlling the interaction of two ionic qubits with their environment, we investigate the capability of noise to generate discord. Firstly, we show that noise acting on only one quantum system can generate discord between two. States generated in this way are restricted in terms of the rank of their correlation matrix. Secondly, we show that classically correlated noise processes are capable of generating a much broader range of discordant states with correlation matrices of any rank. Our results show that noise processes prevalent in many physical systems can automatically generate nonclassical correlations and highlight fundamental differences between discord and entanglement.
authors.affiliation: Institut für Quantenoptik und Quanteninformation, Österreichische Akademie der Wissenschaften, Technikerstrasse 21A, 6020 Innsbruck, Austria and Institut für Experimentalphysik, Universität Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria.
authors.forename: B P
authors.initials: BP
authors.lastname: Lanyon
authors.affiliation: Institut für Quantenoptik und Quanteninformation, Österreichische Akademie der Wissenschaften, Technikerstrasse 21A, 6020 Innsbruck, Austria and Institut für Experimentalphysik, Universität Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria.
authors.forename: P
authors.initials: P
authors.lastname: Jurcevic
authors.affiliation: Institut für Quantenoptik und Quanteninformation, Österreichische Akademie der Wissenschaften, Technikerstrasse 21A, 6020 Innsbruck, Austria and Institut für Experimentalphysik, Universität Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria.
authors.forename: C
authors.initials: C
authors.lastname: Hempel
authors.affiliation: Department of Physics, University of California, Berkeley, California 94720, USA and Physikalisches Institut, Universität Freiburg, Hermann-Herder-Strasse 3, D-79104 Freiburg, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Gessner
authors.affiliation: Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, 117543 Singapore, Singapore and Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom and Department of Physics, National University of Singapore, 2 Science Drive 3, 117542 Singapore, Singapore.
authors.forename: V
authors.initials: V
authors.lastname: Vedral
authors.affiliation: Institut für Quantenoptik und Quanteninformation, Österreichische Akademie der Wissenschaften, Technikerstrasse 21A, 6020 Innsbruck, Austria and Institut für Experimentalphysik, Universität Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria.
authors.forename: R
authors.initials: R
authors.lastname: Blatt
authors.affiliation: Institut für Quantenoptik und Quanteninformation, Österreichische Akademie der Wissenschaften, Technikerstrasse 21A, 6020 Innsbruck, Austria and Institut für Experimentalphysik, Universität Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria.
authors.forename: C F
authors.initials: CF
authors.lastname: Roos