Hannover 2003 – wissenschaftliches Programm
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Q: Quantenoptik
Q 50: Quantenkommunikation
Q 50.8: Vortrag
Freitag, 28. März 2003, 15:45–16:00, F102
Optimal unambiguous discrimination between density matrices — •Philippe Raynal1, Steven van Enk2, and Norbert Lütkenhaus1 — 1Quantum Information Theory Group, Zentrum für Moderne Optik, Erlangen-Nürnberg Universität, Staudtstr. 7/B2 D-91058 Erlangen — 2Bell Labs, Lucent Technologies 600-700 Mountain Ave, Murray Hill NJ 07974
Bounds on the degree of distinguishability of density matrices are an
important tool in the analysis of quatum communications protocols. Here we
consider the error free probabilistic discrimination. This problem has been
studied so far only for pure states [1], though quite often bounds for
mixed
states are required.
In our analysis, we reduce the general problem of discrimination of two
density
matrices to that where the two ranks r1 and r2 add up to the
dimension
of the Hilbert space. In that context, we review previously obtained
results
for pure states (r1=1, r2=1) [1] and pure and mixed states (r1=1
r2=2) [2]. Furthermore, we summarize our researche towards the solution
of
higher classes e.g. r1=1 and r2=N which builds on the
techniques developped
in [2].
[1] For review, see A. Chefles, arXiv:quant-ph/0010114 [2] Y. Sun, J.A. Bergou, M. Hillery, to appear in Physical Review A, arXiv:quant-ph/0112051