Hannover 2003 – scientific programme
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Q: Quantenoptik
Q 37: Quanteninformation 4
Q 37.4: Talk
Thursday, March 27, 2003, 14:45–15:00, F102
Entanglement of 2 × K quantum systems — •Artur Łoziński1,2, Andreas Buchleitner1, Karol Życzkowski2,3, and Thomas Wellens1 — 1Max-Planck-Institut für Physik komplexer Systeme, Nöthnitzer Straße 38, D-01187 Dresden — 2Instytut Fizyki im. Smoluchowskiego, Uniwersytet Jagielloński, ul. Reymonta 4, PL-30-059 Kraków — 3Centrum Fizyki Teoretycznej, Polska Akademia Nauk, Al. Lotników 32/46, PL-02-668 Warszawa
We derive an analytical expression for the lower bound of the concurrence [1] of mixed quantum states of composite 2× K systems. In contrast to other, implicitly defined entanglement measures, the numerical evaluation of our bound is straightforward. We explicitly evaluate its tightness for general mixed states of 2× 3 systems, and identify a large class of states where our expression gives the exact value of the concurrence.
[1] W.K. Wootters, Phys. Rev. Lett. 80, 2245 (1998).