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arXiv · 1305.3069

Quantum parameter estimation affected by unitary disturbance

A. De Pasquale·D. Rossini·P. Facchi·V. Giovannetti
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Abstract

We provide a general framework for handling the effects of a unitary disturbance on the estimation of the amplitude $λ$ associated to a unitary dynamics. By computing an analytical and general expression for the quantum Fisher information, we prove that the optimal estimation precision for $λ$ cannot be outperformed through the addition of such a unitary disturbance. However, if the dynamics of the system is already affected by an external field, increasing its strength does not necessary imply a loss in the optimal estimation precision.

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A. De Pasquale, D. Rossini, P. Facchi, V. Giovannetti. 2013-11-19. Quantum parameter estimation affected by unitary disturbance. https://doi.org/10.1103/physreva.88.052117

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