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Advancement of estimation fidelity in continuous quantum measurement

Lajos Diosi
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Abstract

We estimate an unknown qubit from the long sequence of n random polarization measurements of precision Delta. Using the standard Ito-stochastic equations of the aposteriori state in the continuous measurement limit we calculate the advancement of fidelity. We show that the standard optimum value 2/3 is achieved asymptotically for n >> Delta^2 / 96 >> 1. We append a brief derivation of novel Ito-equations for the estimate state.

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Lajos Diosi. 2002-02-09. Advancement of estimation fidelity in continuous quantum measurement. https://doi.org/10.1088/0305-4470%2F35%2F12%2F311

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