Frankfurt 2006 – wissenschaftliches Programm
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Q: Quantenoptik und Photonik
Q 75: Poster Quanteninformation
Q 75.8: Poster
Donnerstag, 16. März 2006, 16:30–18:30, Labsaal
Experimental Demonstration of a Six Photon Entangled GHZ State — •Alexander Goebel1, Qiang Zhang1,2, Claudia Wagenknecht1, Yu-Ao Chen1, Alois Mair1, and Jian-Wei Pan1,2 — 1Physikalisches Institut, Universität Heidelberg, Philosophenweg 12, D-69120 Heidelberg, Germany — 2Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui, 230027, PR China
Preparation and manipulation of multi-particle entanglement has been a major breakthrough in modern physics. Up to five-particle entanglement has been used to experimentally demonstrate the stunning contradiction between quantum mechanics and local realism. However, many further experiments, such as teleportation of a complex system and quantum error correcetion, require the entanglement of at least six particles, which up to recently has remained an experimental challenge. Here, we report the first experimental demonstration of a six photon entangled Greenberger-Horne-Zeilinger (GHZ) state. In the experiment, we used a pulsed IR laser source to produce short (~200 fsec) UV light pulses via second harmonic generation. Each pulse was directed onto beta barium borate (BBO) crystals to generate three entangled photon pairs via type-II parametric downconversion. All pairs were in a ∣Ψ-> Bell state. Photons 2(4) and 3(5) of the first(second) and second(third) pair were then combined on a polarising beam splitter in order to entangle all three pairs and to generate a six photon GHZ state. We used the process of quantum witness to prove that our system was in fact in a maximally entangled GHZ state.