Hannover 2003 – scientific programme
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Q: Quantenoptik
Q 18: Quanteninformation 3
Q 18.5: Talk
Tuesday, March 25, 2003, 15:00–15:15, F102
Entanglement concentration of Gaussian quantum states — •Stefan Scheel1, Jens Eisert2, Daniel E. Browne1, and Martin B. Plenio1 — 1Quantum Optics and Laser Science, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, UK — 2Universität Potsdam, Institut für Physik, An Neuen Palais 10, 14469 Potsdam
Entangled Gaussian states form a particularly interesting class of continuous-variable quantum states in that they can be generated rather easily and in that they can be used in various quantum information processing tasks. As any other entangled states, they suffer from decoherence and entanglement degradation and the question of distillation or entanglement concentration naturally arises. Recently it has been shown that Gaussian operation alone are not sufficient to implement a distillation protocol for Gaussian quantum states. However, it is not clear which essentially non-Gaussian operations have to be added to achieve this task. In this talk we will be mainly concerned with entanglement concentration using Procrustean methods, in particular photon-counting, that can be implemented with present-day technology. The protocols are based on measurement-induced nonlinearities that are inherent in conditional state-preparation schemes. As a particularly useful application we show how to generate finite-dimensional entangled states from weakly entangled Gaussian states which may serve as the fundamental step in a distillation protocol for Gaussian quantum states.