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Quantum Fisher information as a predictor of decoherence in the preparation of spin-cat states for quantum metrology

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posted on 2023-06-09, 07:19 authored by Samuel Nolan, Simon Haine
In its simplest form, decoherence occurs when a quantum state is entangled with a second state, but the results of measurements made on the second state are not accessible. As the second state has effectively “measured” the first, in this paper we argue that the quantum Fisher information is the relevant metric for predicting and quantifying this kind of decoherence. The quantum Fisher information is usually used to determine an upper bound on how precisely measurements on a state can be used to estimate a classical parameter, and as such it is an important resource. Quantum-enhanced metrology aims to create nonclassical states with large quantum Fisher information and utilize them in precision measurements. In the process of doing this it is possible for states to undergo decoherence; for instance atom-light interactions used to create coherent superpositions of atomic states may result in atom-light entanglement. Highly nonclassical states, such as spin-cat states (Schrödinger cat states constructed from superpositions of collective spins) are shown to be highly susceptible to this kind of decoherence. We also investigate the required field occupation of the second state, such that this decoherence is negligible.

Funding

QBAS; G1862; European Commission; 704672

History

Publication status

  • Published

File Version

  • Published version

Journal

Physical Review A

ISSN

2469-9926

Publisher

American Physical Society

Issue

4

Volume

95

Page range

043642

Department affiliated with

  • Mathematics Publications

Research groups affiliated with

  • Atomic, Molecular and Optical Physics Research Group Publications

Full text available

  • Yes

Peer reviewed?

  • Yes

Legacy Posted Date

2017-07-21

First Open Access (FOA) Date

2017-07-21

First Compliant Deposit (FCD) Date

2017-07-21

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