Frankfurt 2006 – scientific programme

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Q: Quantenoptik und Photonik

Q 50: Quanteninformation IV

Q 50.1: Talk

Wednesday, March 15, 2006, 14:00–14:15, HI

Quantum estimation of damping — •Hannah Venzl and Matthias Freyberger — Abteilung Quantenphysik, Universität Ulm, 89069 Ulm

It is generally not possible to transmit a signal error free, since there is always a coupling to the external environment due to imperfections of the transmitting medium. This coupling causes dissipation and decoherence effects. It is thus of great interest to get as much information as possible about the unknown damping constant.

We discuss a quantum interferometric approach to the estimation of damping. We study both entangled and separable probe states consisting of superpositions of coherent states, since for those states an analytical description of damping is available. The effect of damping on such states is analysed using a suitable generalised homodyne detection. We investigate whether entanglement can improve the estimation of an unknown damping constant.