Generalized phase estimation in noisy quantum gates
We examine metrological scenarios where the parameter of interest is encoded onto a quantum state through the action of a noisy quantum gate and investigate the ultimate bound to precision by analyzing the behaviour of the Quantum Fisher Information (QFI). We focus on qubit gates and consider the po...
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Main Authors | , , , |
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Format | Journal Article |
Language | English |
Published |
03.06.2024
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Subjects | |
Online Access | Get full text |
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Summary: | We examine metrological scenarios where the parameter of interest is encoded
onto a quantum state through the action of a noisy quantum gate and investigate
the ultimate bound to precision by analyzing the behaviour of the Quantum
Fisher Information (QFI). We focus on qubit gates and consider the possibility
of employing successive applications of the gate. We go beyond the trivial case
of unitary gates and characterize the robustness of the metrological procedure
introducing noise in the performed quantum operation, looking at how this
affects the QFI at different steps (gate applications). We model the dephasing
and tilting noise affecting qubit rotations as classical fluctuations governed
by a Von Mises-Fisher distribution. Compared to the noiseless case, in which
the QFI grows quadratically with the number of steps, we observe a non
monotonic behavior, and the appearance of a maximum in the QFI, which defines
the ideal number of steps that should be performed in order to precisely
characterize the action of the gate. |
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DOI: | 10.48550/arxiv.2406.01590 |