Hannover 2003 – wissenschaftliches Programm

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Q: Quantenoptik

Q 1: Quanteninformation 1: Gruppenberichte

Q 1.2: Gruppenbericht

Montag, 24. März 2003, 11:30–12:00, F102

Elements of Quantum Networks — •A. Kuhn, M. Hennrich, M. Hijlkema, P. Krok, T. Legero, S. Nussmann, F. Rohde, B. Weber, T. Wilk, and G. Rempe — Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Str. 1, 85748 Garching, Germany

A quantum network that allows all-optical quantum information processing will be based on indistinguishable photons that carry information between different quantum gates or memories [1]. Gate operations require network nodes in form of linear optical elements, while storage and retrieval of qubits could be accomplished either by isolated single atoms acting as quantum memories, or by dark-state polaritons in atomic ensembles. Our work is focussed on the demonstration of these elementary quantum network links and nodes. We use narrowband and transform-limited single-photon pulses, which are provided by a cavity-QED system that employs a controlled energy exchange between an atom and the quantized field of the cavity [2]. The analysis of the photon statistics shows that photons are emitted one-by-one, so that they can be used for an experimental feasibility study of all-optical quantum information processing based on second-order interference of indistinguishable photons. We present first results that demonstrate the expected occurence of two-photon quantum correlations. Furthermore, we present work on a quantum register, which is designed for quantum information processing with atoms held at rest inside a high-finesse optical cavity by means of a dipole-force trap.

[1] Cirac et al. PRL 78, 3221 (1997); Knill et al. Nature 409, 46 (2001)

[2] Hennrich et al. PRL 85, 4872 (2000); Kuhn et al. PRL 89, 67901 (2002)