Distributed quantum sensing with squeezed-vacuum light in a configurable array of Mach-Zehnder interferometers

Year: 2023

Authors: Malitesta M., Smerzi A., Pezzè L.

Autors Affiliation: QSTAR, INO CNR & LENS, Largo Enr Fermi 2, I-50125 Florence, Italy; Univ Napoli Feder II, Dipartimento Biol, Via Cinthia 21, I-80126 Naples, Italy.

Abstract: We study an entangled distributed quantum sensing scheme based on an array of d Mach-Zehnder interferometers (MZIs) for the estimation of relative phase shifts. The scheme uses d coherent states and a single squeezed-vacuum state that is distributed among the MZIs by a quantum circuit (QC). The protocol can be optimized analytically: it overcomes the shot-noise limit and reaches the Heisenberg limit with respect to the average total number of probe particles, n(T) , for the estimation of arbitrary linear combinations of the d phases. We compare the entangled strategy with a separable one that uses d coherent and d squeezed-vacuum states and the same n(T) . The entangled strategy benefits for a substantial reduction of resource overhead and can achieve a maximum gain equal to d when using the same total squeezed-light intensity as the separable strategy. Interestingly, the entangled strategy using a single squeezed-vacuum state can reach the same sensitivity as the separable strategy that uses d copies of the same state. Finally, given a random choices of the QC, we identify the optimal linear combination of the phases that can be estimated with maximum sensitivity. Our scheme paves the ways for a variety of applications in distributed quantum sensing with photonic and atomic interferometers.

Journal/Review: PHYSICAL REVIEW A

Volume: 108 (3)      Pages from: 32621-1  to: 32621-24

More Information: We thank R. Corgier and V. Gebhart for discussions. We acknowledge financial support from the European Union’s Horizon 2020 Qombs Project (FET Flagship on Quantum Technologies Grant No. 820419) and the QuantEra grant SQUEIS.
KeyWords: States; Limits; Noise
DOI: 10.1103/PhysRevA.108.032621

Citations: 3
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