Hannover 2010 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 52: Quantum Information: Concepts and Methods IV / Photons and Nonclassical Light I
Q 52.5: Talk
Thursday, March 11, 2010, 15:00–15:15, E 214
Experimental entanglement of a six-photon symmetric Dicke state — •Witlef Wieczorek1,2, Roland Krischek1,2, Nikolai Kiesel1,2, Patrick Michelberger1,2, Geza Toth3,4, and Harald Weinfurter1,2 — 1Max-Planck-Institut für Quantenoptik, D-85748 Garching — 2Department für Physik, LMU München, D-80799 München — 3IKERBASQUE and Department of Theoretical Physics, The University of the Basque Country, E-48080 Bilbao — 4Research Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, H-1525 Budapest
We report on the experimental implementation of a symmetric Dicke state with six photonic qubits [1]. The necessary photons are generated by the use of a novel SPDC photon source based on a femtosecond UV enhancement cavity. To observe the Dicke state, photons from this SPDC source, arranged for collinear type II emission, are symmetrically distributed by polarization-independent beam splitters into six spatial modes. We discuss characteristic properties of Dicke states with respect to their relevance for applications in quantum information protocols and for quantum metrology. For our experimental analysis we introduce efficient tools, which require significantly fewer measurement settings than a full reconstruction of the density matrix, in order to determine the fidelity and to prove genuine multi-partite entanglement [2].
[1] W. Wieczorek et al., Phys. Rev. Lett. 103, 020504 (2009); R. Prevedel et al., ibid., 020503.
[2] G. Tóth et al., New J. Phys. 11, 083002 (2009).