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Q: Quantenoptik
Q 43: Quanteninformation IV
Q 43.6: Vortrag
Freitag, 7. April 2000, 13:15–13:30, HS X
Best seperability approximation — •Sinisa Karnas, Maciej Lewenstein und Anna Sanpera — Inst. f. Theoret. Physik, Universität Hannover
We have recently developed a method of characterizing density matrices in M× N dimensional Hilbert spaces via the “best separable approximations” of the form ρ=Λρs +(1−Λ)δρ where ρs is separable, Λ is maximal, and δρ does not contain any product vectors in its range. We have been able to investigate the uniqueness of the above expansion for arbitrary M, and N, and for multicomposite systems we have shown that generic separable approximations for low dimensional systems corresponds to generalized Werner states, i.e. mixtures of a separable matrix of full range with a single projector on a maximally entangled state.