Heidelberg 2015 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 15: Poster: Quantum Optics and Photonics I

Q 15.76: Poster

Montag, 23. März 2015, 17:00–19:00, C/Foyer

Models of coherent averaging for quantum enhanced measurements — •Julien Fraisse1,2 and Daniel Braun1,21Laboratoire de physique théorique, Université Paul Sabatier, 118 route de Narbonne Toulouse, France — 2Institut für Theoretische Physik, Eberhard-Karls-Universität Tübingen, Auf der Morgenstelle 14 Tübingen, Germany

We are interested in the "coherent averaging’ method’ which comprises coupling N quantum resources (probes) to a (N+1) system, called quantum bus and reading out the latest. It was already shown that this method allows one to reach the Heisenberg scaling (standard deviation of the estimation that scales as 1/N with the number of quantum resources N) in estimating a parameter linked to the interaction.

We expand this result to the estimation of a parameter linked to the free Hamiltonian of the probes, adding some constraints on the Hamiltonian, and we discuss the range of validity of our result. We study both analytically and numerically a qubit model (probes and bus are qubits) of coherent averaging. QFI calculations have been performed for this model and used to verify the general theory. We use the numerical calculation to check if the Heisenberg scaling still exists when the analytical result is not valid anymore.

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DPG-Physik > DPG-Verhandlungen > 2015 > Heidelberg