Achieving sub-shot-noise sensing at finite temperatures

Mehboudi, Mohammad, Correa, Luis A. and Sanpera, Anna (2016) Achieving sub-shot-noise sensing at finite temperatures. Physical Review A, 94 (4). 042121/1-042121/7. ISSN 2469-9934

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We investigate sensing of magnetic fields using quantum spin chains at finite temperature and exploit quantum phase crossovers to improve metrological bounds on the estimation of the chain parameters. In particular, we analyze the XX spin chain and show that the magnetic sensitivity of this system is dictated by its adiabatic magnetic susceptibility, which scales extensively (linearly) in the number of spins N. Next, we introduce an iterative feedforward protocol that actively exploits features of quantum phase crossovers to enable super-extensive scaling of the magnetic sensitivity. Moreover, we provide experimentally realistic observables to saturate the quantum metrological bounds. Finally, we also address magnetic sensing in the Heisenberg XY spin chain.

Item Type: Article
Additional Information: ©2016 American Physical Society
Schools/Departments: University of Nottingham, UK > Faculty of Science > School of Mathematical Sciences
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Depositing User: Correa Marichal, Luis
Date Deposited: 03 Oct 2017 10:15
Last Modified: 04 May 2020 18:16

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