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Q: Quantenoptik
Q 223: Quantum Information II
Q 223.7: Vortrag
Dienstag, 5. März 2002, 18:00–18:15, HS 11/215
Telecloning of continuous quantum variables — •Peter van Loock1,2 and Samuel Braunstein1 — 1Informatics, University of Wales, Bangor, United Kingdom — 2Quantum Information Theory Group, Zentrum für Moderne Optik, Universität Erlangen-Nürnberg
The performance of a “multiuser quantum channel” (MQC) for conveying quantum information simultaneously to several receivers is inevitably restricted by the no-cloning theorem: an MQC can only distribute approximate (ideally optimal) clones among the receivers. Such a “telecloning” scheme must rely on entanglement, because the optimal cloning fidelities always exceed those attainable through non-entanglement based classical teleportation. We propose a multimode multiparty entangled state as an MQC for continuous-variable communication [1]. It is producible with squeezed light and linear optics and enables optimal symmetric telecloning of coherent states. With respect to its degree of entanglement, our MQC is “cheaper” than the MQC’s of existing telecloning protocols involving discrete variables [2].
[1] P. van Loock and Samuel L. Braunstein, Phys. Rev. Lett. 87, 247901 (2001).
[2] M. Murao, M. B. Plenio, and V. Vedral, Phys. Rev. A 61, 032311 (2000).