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Q: Quantenoptik und Photonik

Q 75: Poster Quanteninformation

Q 75.14: Poster

Thursday, March 16, 2006, 16:30–18:30, Labsaal

Real-valued representations in quantum mechanics and decoherence — •Volker Schauer, Alexander Wolf, and Matthias Freyberger — Abteilung Quantenphysik, Universität Ulm, 89069 Ulm, Germany

The problem of representing a quantum state is discussed since the early days of quantum mechanics. We give a representation of a quantum state as the real part of an entire function on a closed path in complex plane. The quantum state is therefore completely encoded in a real-valued function of just one variable. This representation is closely linked to entangled position and momentum measurements on a coupled system, which uses a Schroedinger cat-like state as a reference state. Therefore, these measurements can be used to reconstruct nonclassical states. Moreover the corresponding algorithm turns out to be stable with respect to decoherence since we can correct the measurement data by a rescaling procedure.