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arXiv · 2106.03101

Quantum estimation of a time dependent perturbation

Claus Normann Madsen·Lia Valdetaro·Klaus Mølmer
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Abstract

We analyze the estimation of a time dependent perturbation acting on a continuously monitored quantum system. We describe the temporal fluctuations of the perturbation by a Hidden Markov Model, and we combine quantum measurement theory and classical filter theory into a time evolving hybrid quantum and classical trajectory. The forward-backward analysis that permits smoothed estimates of classical Hidden Markov Models has a counterpart in the theory of retrodiction and Past Quantum States. As a specific example, we apply our hybrid trajectory and Past Quantum State theory to the sensing of a fluctuating magnetic field by microwave interrogation of a single quantum spin.

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Claus Normann Madsen, Lia Valdetaro, Klaus Mølmer. 2021-06-06. Quantum estimation of a time dependent perturbation. https://arxiv.org/abs/2106.03101

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