Hamburg 2009 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 34: Quanteninformation: Konzepte IV
Q 34.3: Vortrag
Mittwoch, 4. März 2009, 14:30–14:45, VMP 6 HS-D
Entanglement properties of Werner-like three-qubit states — •Christopher Eltschka and Jens Siewert — Institut für theoretische Physik, Universität Regensburg, D-93040 Regensburg, Germany
We analyse the entanglement properties of the Werner-like three-qubit states of the form ρ(p) = p|GHZ><GHZ| + (1−p)ρmixed, where |GHZ> = (|000>+|111>)/√2 is the three-qubit GHZ state, and ρmixed is the completely mixed three-qubit state. Using geometrical considerations in the space of density matrices, we estimate the maximal value of p for which the three-tangle vanishes, i.e. the maximal p for which ρ(p) describes a W-class state. We give an optimal decomposition for that state, and from that try to derive an optimal GHZ\ W witness.