Düsseldorf 2007 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 18: Quanteninformation (Verschränkung und Dekohärenz I)

Q 18.7: Talk

Tuesday, March 20, 2007, 12:15–12:30, 5L

Full experimental characterization of Gaussian entangled states — •James DiGuglielmo, Boris Hage, Alexander Franzen und Roman Schnabel — Max-Planck-Institut für Gravitationsphysik (Albert-Einstein-Institut),Institut für Gravitationsphysik, Leibniz Universität Hannover,Callinstr. 38, 30167 Hannover

A quantitative characterization of quantum information communication channels by means of quantities such as the von Neumann entropy and quantum capacity require the full knowledge of the entangled EPR state being used to establish the channel. For Gaussian states, this can be achieved by measuring the covariance matrix. To this end we present an experimental procedure for the measurement of the entire covariance matrix using as few measurements as possible. We apply this method to the characterization of three different types of EPR states and then use the reconstructed matrices to obtain the lower bound to the quantum channel capacity as well as other information theoretic quantities such as the partial information. The purity and logarithmic negativity are calculated as well.