Entanglement Enhanced Sensing with Qubits affected by non-Markovian Dephasing

Fuente: arXiv
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Autori principali: Kaufmann, Noah, Nielsen, Kasper H., González-Ruiz, Eva M., Sørensen, Anders S.
Natura: Preprint
Pubblicazione: 2026
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author Kaufmann, Noah
Nielsen, Kasper H.
González-Ruiz, Eva M.
Sørensen, Anders S.
author_facet Kaufmann, Noah
Nielsen, Kasper H.
González-Ruiz, Eva M.
Sørensen, Anders S.
contents Entanglement has been proposed as a means to improve the sensitivity of sensing weak signals. While the degree of this quantum advantage is well understood in noiseless settings, the situation is more complex under realistic conditions, where the system is subject to decoherence. In this case, the enhancement depends on the specific noise characteristics. Previous treatments of colored noise typically assume that the noise is uncorrelated between successive experiments. Here, we consider the scenario in which the noise exhibits correlations across multiple shots. We derive a simple fundamental limit to the sensitivity based on the fact that the sensitivity cannot be better than the signal-to-noise ratio seen by the probe. Focusing on Ramsey spectroscopy with probes affected by pure classical dephasing, we show that, for suitable spatial and temporal noise correlations, entangled probes achieve a better scaling of the sensitivity with the number of probes than separable states. This demonstrates that entanglement can provide a substantial improvement for Ramsey spectroscopy subject to correlated noise.
format Preprint
id arxiv_https___arxiv_org_abs_2604_22368
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Entanglement Enhanced Sensing with Qubits affected by non-Markovian Dephasing
Kaufmann, Noah
Nielsen, Kasper H.
González-Ruiz, Eva M.
Sørensen, Anders S.
Quantum Physics
Entanglement has been proposed as a means to improve the sensitivity of sensing weak signals. While the degree of this quantum advantage is well understood in noiseless settings, the situation is more complex under realistic conditions, where the system is subject to decoherence. In this case, the enhancement depends on the specific noise characteristics. Previous treatments of colored noise typically assume that the noise is uncorrelated between successive experiments. Here, we consider the scenario in which the noise exhibits correlations across multiple shots. We derive a simple fundamental limit to the sensitivity based on the fact that the sensitivity cannot be better than the signal-to-noise ratio seen by the probe. Focusing on Ramsey spectroscopy with probes affected by pure classical dephasing, we show that, for suitable spatial and temporal noise correlations, entangled probes achieve a better scaling of the sensitivity with the number of probes than separable states. This demonstrates that entanglement can provide a substantial improvement for Ramsey spectroscopy subject to correlated noise.
title Entanglement Enhanced Sensing with Qubits affected by non-Markovian Dephasing
topic Quantum Physics
url https://arxiv.org/abs/2604.22368