Hannover 2016 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 37: Quantum Information: Concepts and Methods VI
Q 37.3: Vortrag
Mittwoch, 2. März 2016, 15:00–15:15, e214
Upper bound for SL-invariant entanglement measures for mixed states of arbitrary rank — •Andreas Osterloh — Universität Duisburg-Essen, Lotharstr. 1, 47048 Duisburg, Germany.
I present an alternative algorithm to ref. [1], exploiting the knowledge obtained for the rank-two case. Whereas the known algorithm has an advantage of taking into consideration the whole range of the density matrix ρ, it on the other hand has the disadvantage of searching in a high-dimensional Hilbert space: imagine the states |ψi⟩, where E[ |ψi⟩] vanishes; the algorithm then calculates the distance to the baricenter of them as an upper bound of E, which comes with a disadvantage, of course.
Here, I only consider rank two states but calculate the upper bound obtained by the method presented in [2,3]. I discuss examples where the advantage of the new algorithm is obvious, but also highlight on the obvious disadvantage of only considering rank two parts of ρ.
[1] S. Rodriques, N. Datta, and P. Love, Phys. Rev. A 90, 012340 (2014).
[2] R. Lohmayer, A. Osterloh, J. Siewert, and A. Uhlmann, Phys. Rev. Lett. 97, 260502 (2006).
[3] A. Osterloh, J. Siewert, and A. Uhlmann, Phys. Rev. A 77, 032310 (2008).