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Achieving sub-shot-noise sensing at finite temperatures

Mehboudi, Mohammad; Correa, Luis A.; Sanpera, Anna


Mohammad Mehboudi

Luis A. Correa

Anna Sanpera


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.


Mehboudi, M., Correa, L. A., & Sanpera, A. (2016). Achieving sub-shot-noise sensing at finite temperatures. Physical Review A, 94(4), Article 042121.

Journal Article Type Article
Acceptance Date Oct 21, 2016
Publication Date Oct 21, 2016
Deposit Date Oct 3, 2017
Publicly Available Date Oct 3, 2017
Journal Physical Review A
Print ISSN 2469-9926
Electronic ISSN 2469-9934
Publisher American Physical Society
Peer Reviewed Peer Reviewed
Volume 94
Issue 4
Article Number 042121
Public URL
Publisher URL
Additional Information ©2016 American Physical Society


PhysRevA.94.042121.pdf (875 Kb)

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