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Multiparameter estimation in networked quantum sensors
journal contribution
posted on 2023-06-09, 09:19 authored by Timothy J Proctor, Paul A Knott, Jacob DunninghamJacob DunninghamWe introduce a general model for a network of quantum sensors, and we use this model to consider the following 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 nonlinear 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.
Funding
UK Quantum Technology Hub: NQIT-Networked Quantum Information Technologies; G1503; EPSRC-ENGINEERING & PHYSICAL SCIENCES RESEARCH COUNCIL; EP/M013243/1
History
Publication status
- Published
File Version
- Accepted version
Journal
Physical Review LettersISSN
0031-9007Publisher
American Physical SocietyExternal DOI
Issue
8Volume
120Article number
a080501Department affiliated with
- Physics and Astronomy Publications
Research groups affiliated with
- Sussex Centre for Quantum Technologies Publications
Full text available
- Yes
Peer reviewed?
- Yes
Legacy Posted Date
2017-12-12First Open Access (FOA) Date
2017-12-12First Compliant Deposit (FCD) Date
2017-12-12Usage metrics
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