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Q: Quantenoptik und Photonik
Q 73: Quantencomputer
Q 73.2: Talk
Wednesday, March 9, 2005, 14:15–14:30, HU 2002
Experimental Cluster State Quantum Computing — •Philip Walther1, Kevin Resch1, Terry Rudolph2, Emmanuel Schenck1, Harald Weinfurter3, Markus Aspelmeyer1, and Anton Zeilinger1,4 — 1Institut für Experimentalphysik, Universität Wien, Boltzmanngasse 5, 1090 Vienna, Austria — 2QOLS, Blackett Laboratory, Imperial College London, London SW7 2BW, United Kingdom — 3LMU München, Sektion Physik,Schellingstraße 4/III, D-80799 München — 4Institut für Quantenoptik und Quanteninformation, Österreichische Akademie der Wissenschaften, Boltzmanngasse 3, 1090 Vienna, Austria
We have experimentally realized four-qubit cluster states encoded into the polarization state of four photons, in which each qubit can be individually addressed. Very recently, these cluster states haven been proposed as a new architecture for quantum computation, which requires the quantum computer to be initialized in such a highly-entangled cluster state. From this point, the quantum computation proceeds by a sequence of single-qubit measurements with classical feedforward of their outcomes. Because of the essential role of measurement this quantum computer is irreversible and thus one-way. In the one-way quantum computer the order and choices of measurements determine the algorithm computed. We fully characterize the quantum state by implementing the first experimental four-qubit quantum state tomography and explore the state’s relevant entanglement properties. Using this cluster state we perform the first demonstration of one-way quantum computing through a universal set of one- and two-qubit operations.