München 2004 – scientific programme
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Q: Quantenoptik und Photonik
Q 2: Quanteninformation I
Q 2.8: Talk
Monday, March 22, 2004, 15:45–16:00, HS 101
Cloning Gaussian States — •Ole Krüger1, Reinhard F. Werner1, and Michael M. Wolf2 — 1Institut für Mathematische Physik, TU Braunschweig, Germany — 2Max-Planck-Institut für Quantenoptik, Garching, Germany
Bright laser beams offer a practicable alternative for the realization of quantum information tasks. In particular, they play an important role in the transmission of quantum information over large distances. The simultaneous access of third parties to this information during transmission is governed by the restrictions on cloning. This is important for the procedures of quantum cryptography.
The theoretical description of such beams is based on states of continuous variable systems, most notably Gaussian states. Unifying and extending previous approaches, we consider the question of optimal cloning of Gaussian states under various settings. These include different figure of merit functionals, joint vs. single-copy comparison and covariance properties. We especially investigate in which sense, i. e. for which settings, cloners with Gaussian output states are optimal.