Dresden 2011 – wissenschaftliches Programm
Q 20.8: Vortrag
Dienstag, 15. März 2011, 12:15–12:30, SCH A118
Permutationally Invariant Quantum Tomography — •Géza Tóth1,2,3, Witlef Wieczorek4,5, David Gross6, Roland Krischek4,5, Christian Schwemmer4,5, and Harald Weinfurter4,5 — 1Theoretical Physics, The University of the Basque Country, E-48080 Bilbao, Spain — 2IKERBASQUE, Basque Foundation for Science, E-48011 Bilbao, Spain — 3Research Institute for Solid State Physics and Optics, H-1525 Budapest, Hungary — 4Max-Planck-Institut für Quantenoptik, D-85748 Garching, Germany — 5Fakultät für Physik, Ludwig-Maximilians-Universität, D-80799 Garching, Germany — 6Institute for Theoretical Physics, Leibniz University Hannover, D-30167 Hannover, Germany
We present a scalable method for the tomography of large multi-qubit quantum registers. It acquires information about the permutationally invariant part of the density operator, which is a good approximation to the true state in many, relevant cases. Our method gives the best measurement strategy to minimize the experimental effort as well as to minimize the uncertainties of the reconstructed density matrix. We calculate the measurements needed for up to 14 qubits, and also compute the required total count, i.e., how many times the experiments have to be repeated for obtaining sufficiently low uncertainties. We note that the method has been implemented for the experimental tomography of a four-qubit symmetric Dicke state .
 See the talk by C. Schwemmer et al.