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Q: Fachverband Quantenoptik und Photonik
Q 57: Quanteninformation (Quantencomputer II)
Q 57.5: Vortrag
Donnerstag, 22. März 2007, 15:15–15:30, 5L
High-speed linear optics quantum computing using active feed-forward — •Robert Prevedel1, Philip Walther1,2, Felix Tiefenbacher1,3, Pascal Böhi1, Rainer Kaltenbaek1, Thomas Jennewein3, and Anton Zeilinger1,3 — 1Institute for Experimental Physics, University of Vienna, Boltzmanngasse 5, A-1090 Vienna, Austria — 2Physics Department, Harvard University, Cambridge, Massachusetts 02138, USA — 3Institute for Quantum Optics and Quantum Information (IQOQI), Austrian Academy of Sciences, Boltzmanngasse 3, A-1090 Vienna, Austria
Quantum computers promise to be more efficient and powerful than their classical counterparts. In the one-way quantum computer model, a sequence of measurements processes qubits, which are initially prepared in a highly entangled cluster state. The key advantage of this scheme over the standard network approach of quantum computing is that inherent, randomly induced measurement errors can classically be fed-forward and corrected by adapting the basis of subsequent measurements. Active feed-forward is therefore crucial to achieve deterministic quantum computing once a cluster state is prepared. We have experimentally realized such a feed-forward one-way quantum computation scheme by employing up to three active-switching Electro-Optical Modulators (EOM) in a four-qubit cluster state encoded into the polarization state of four photons. Using these switches we demonstrate one- and two-qubit gate operations as well as Grover's quantum search algorithm. With present technology this feed-forward step can be performed in less than 150 nanoseconds.