Dresden 2011 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 53: Quantum Information: Photons and Nonclassical Light 1
Q 53.3: Talk
Thursday, March 17, 2011, 15:00–15:15, SCH 251
Useful multiparticle entanglement applied for sub shot noise phase estimation — •Roland Krischek1,2, Christian Schwemmer1,2, Witlef Wieczorek1,2,3, Harald Weinfurter1,2, Philipp Hyllus4, Luca Pezzé5, and Augusto Smerzi4 — 1Max-Planck-Institut für Quantenoptik, D-85748 Garching, Germany, — 2Fakultät für Physik, Ludwig-Maximilians-Universität München, D-80799 München, Germany — 3University of Vienna, Faculty of Physics, Boltzmanngasse 5, A-1090 Vienna, Austria — 4BEC-CNR-INFM and Dipartimento di Fisica, Università di Trento, I-38050 Povo, Italy — 5Laboratoire Charles Fabry de l’Institut d’Optique, F-91403 Orsay Cedex, France
The goal of quantum enhanced metrology is to develop methods to improve the precision of measurements using non-classical resources. To this aim, a parameter, for example, a phase shift has to be determined with a precision beyond the classical shot noise limit. In general, quantum correlations are necessary but not sufficient to achieve measurement sensitivities beyond the shot noise limit. Therefore we developed theoretically and demonstrated experimentally for a 4 photon symmetric Dicke state the condition to recognize useful multiparticle entanglement for the estimation of an unknown phase shift. We implemented a maximum likelihood as well as a Bayesian phase estimation protocol and demonstrate the enhanced sensitivity obtained for an entangled symmetric Dicke state.