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Local versus global strategies in multi-parameter estimation

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Version 2 2023-06-12, 08:34
Version 1 2023-06-09, 04:07
journal contribution
posted on 2023-06-12, 08:34 authored by P A Knott, T J Proctor, A J Hayes, J F Ralph, P Kok, Jacob DunninghamJacob Dunningham
We consider the problem of estimating multiple phases using a multi-mode interferometer. In this setting we show that while global strategies that estimate all the phases simultaneously can lead to high precision gains, the same enhancements can be obtained with local strategies where each phase is estimated individually. A key resource for the enhancement is shown to be a large particle-number variance in the probe state, and for states where the total particle number is not fixed, this can be obtained for mode-separable states and the phases can be read out with local measurements. This has important practical implications because local strategies are generally preferred to global ones for their robustness to local estimation failure, flexibility in the distribution of resources, and comparatively easier state preparation. We obtain our results by analyzing two different schemes: the first uses a set of interferometers, which can be used as a model for a network of quantum sensors, and the second looks at measuring a number of phases relative to a reference, which is concerned primarily with quantum imaging.

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

  • Published version

Journal

Physical Review A

ISSN

1050-2947

Publisher

American Physical Society

Issue

6

Volume

94

Article number

a2312

Department affiliated with

  • Physics and Astronomy Publications

Research groups affiliated with

  • Atomic, Molecular and Optical Physics Research Group Publications

Full text available

  • Yes

Peer reviewed?

  • Yes

Legacy Posted Date

2016-11-22

First Open Access (FOA) Date

2016-11-22

First Compliant Deposit (FCD) Date

2016-11-22

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