Achieving sub-shot-noise sensing at finite temperatures

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

Abstract

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.

Citation

Mehboudi, M., Correa, L. A., & Sanpera, A. (2016). Achieving sub-shot-noise sensing at finite temperatures. Physical Review A, 94(4), Article 042121. https://doi.org/10.1103/PhysRevA.94.042121

• 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
• DOI: https://doi.org/10.1103/PhysRevA.94.042121
• Public URL: https://nottingham-repository.worktribe.com/output/822300
• Publisher URL: https://link.aps.org/doi/10.1103/PhysRevA.94.042121
• Additional Information: ©2016 American Physical Society