Hannover 2016 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 8: Quantum Information: Concepts and Methods II
Q 8.5: Talk
Monday, February 29, 2016, 15:30–15:45, e214
How long does it take to obtain a physical density matrix? — •Lukas Knips1,2, Christian Schwemmer1,2, Nico Klein1,2, Jonas Reuter3, Géza Tóth4,5,6, and Harald Weinfurter1,2 — 1Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, D-85748 Garching — 2Department für Physik, Ludwig-Maximilians-Universität, D-80797 München — 3Bethe Center for Theoretical Physics, Universität Bonn, D-53115 Bonn — 4Department of Theoretical Physics, University of the Basque Country UPV/EHU, P.O. Box 644, E-48080 Bilbao, Spanien — 5IKERBASQUE, Basque Foundation for Science, E-48013 Bilbao, Spanien — 6Wigner Research Centre for Physics, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest, Ungarn
The statistical nature of measurements easily causes unphysical estimates in quantum state tomography. We show that multinomial or Poissonian noise results in eigenvalue distributions converging to the Wigner semicircle distribution for already a modest number of qubits. In this talk, I will show that this fact can be used to specify the number of measurements necessary to avoid unphysical solutions as well as a new approach to convert unphysical estimates into physical ones.