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An Isaac Newton Institute Workshop

Quantum Statistics - quantum measurements, estimation and related topics

OPTIMAL REALIZATION OF NON-UNITARY MAPS FOR QUANTUM INFORMATION

Author: Francesco De Martini (Universita' di Roma "La Sapienza", Italy 00185)

Abstract

It is well known that several state transformations, allowed in the framework of classical information theory, cannot be realized exactly in the quantum realm. Precisely, these correspond to the non “Completely Positive” (Non-CP) Maps wich play a substantial role in fundamental issues as the superluminal signaling in Einstein-Podolsky-Rosen correlations or within any universal “spin flip” process. We outline the behaviour of the most important Non-CP Maps of general relevance in quantum information and the strategy adopted to implement them “optimally” and “universally”. All that will be substantiated by corresponding experiments based on two different methods of modern quantum optics: the photon stimulated emission process in a quantum injected optical parametric amplifier or the Ou-Mandel quantum-state photon symmetrization procedure.