Hannover 2010 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 52: Quantum Information: Concepts and Methods IV / Photons and Nonclassical Light I

Q 52.1: Vortrag

Donnerstag, 11. März 2010, 14:00–14:15, E 214

Quantifying entanglement with covariance matrices — •Oleg Gittsovich and Otfried Gühne — Institut für Quantenoptik und Quanteninformation, Technikerstrasse 21a, A-6020, Innsbruck, Österreich

Covariance matrices are a useful tool to investigate correlations and entanglement in quantum systems. They are widely used in continuous variable systems, but recently also for finite dimensional systems powerful entanglement criteria in terms of covariance matrices have been derived. We show how these results can be used for a quantification of entanglement in bipartite systems. To that aim we introduce an entanglement parameter that quantifies the violation of the covariance matrix criterion and can be used to give a lower bounds on the concurrence. These lower bounds are easily computable and give entanglement estimates for many weakly entangled states.