Heidelberg 1999 – wissenschaftliches Programm
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SYQI: Symposium Quanteninformationsverarbeitung
SYQI 2: Quanteninformationsverarbeitung II
SYQI 2.5: Vortrag
Montag, 15. März 1999, 15:15–15:30, PH1
Lower Bounds for Attainable Fidelities in Entanglement Purification — •Geza Giedke1, Hans J. Briegel1,2, Ignacio Cirac1, and Peter Zoller1 — 1Institut für Theoretische Physik, Universität Innsbruck, A–6020 Innsbruck — 2Sektion Physik, Ludwig-Maximilians-Universität, Theresienstr. 37, D–80333 München
We derive lower bounds for the attainable fidelity of standard entanglement purification protocols when local operations and measurements are subjected to errors. We introduce an error parameter which measures the distance between the ideal completely positive map describing a purification step and the one in the presence of errors. We derive non–linear maps for a lower bound of the fidelity at each purification step in terms of this parameter. From these we obtain expressions for an error threshold and for lower bounds for the asymptotically attainable fidelity.