Multiparameter Estimation in Networked Quantum Sensors

Proctor, Timothy J.; Knott, Paul A.; Dunningham, Jacob A.

doi:10.1103/PhysRevLett.120.080501

Title: Multiparameter Estimation in Networked Quantum Sensors

Journal Article · 21 February 2018 · Physical Review Letters

DOI: https://doi.org/10.1103/PhysRevLett.120.080501 · OSTI ID:1429719

Proctor, Timothy J. ^[1]; Knott, Paul A. ^[2]; Dunningham, Jacob A. ^[3]

Sandia National Lab. (SNL-CA), Livermore, CA (United States); Univ. of California, Berkeley, CA (United States)
Univ. of Nottingham (United Kingdom); Univ. of Sussex, Brighton (United Kingdom)
Univ. of Sussex, Brighton (United Kingdom)

We introduce a general model for a network of quantum sensors, and we use this model to consider the question: When can entanglement between the sensors, and/or global measurements, enhance the precision with which the network can measure a set of unknown parameters? We rigorously answer this question by presenting precise theorems proving that for a broad class of problems there is, at most, a very limited intrinsic advantage to using entangled states or global measurements. Moreover, for many estimation problems separable states and local measurements are optimal, and can achieve the ultimate quantum limit on the estimation uncertainty. This immediately implies that there are broad conditions under which simultaneous estimation of multiple parameters cannot outperform individual, independent estimations. Our results apply to any situation in which spatially localized sensors are unitarily encoded with independent parameters, such as when estimating multiple linear or non-linear optical phase shifts in quantum imaging, or when mapping out the spatial profile of an unknown magnetic field. We conclude by showing that entangling the sensors can enhance the estimation precision when the parameters of interest are global properties of the entire network.

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Research Organization:: Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

Sponsoring Organization:: USDOE National Nuclear Security Administration (NNSA)

Grant/Contract Number:: AC04-94AL85000; NA0003525

OSTI ID:: 1429719

Alternate ID(s):: OSTI ID: 1422465

Report Number(s):: SAND-2017-13642J; PRLTAO; 659588; TRN: US1802617

Journal Information:: Physical Review Letters, Vol. 120, Issue 8; ISSN 0031-9007

Publisher:: American Physical Society (APS)Copyright Statement

Country of Publication:: United States

Language:: English

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Cited by: 136 works

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