Quantum-limited metrology with product states

Boixo, Sergio, Datta, Animesh, Flammia, Steven T., Shaji, Anil, Bagan, Emilio and Caves, Carlton M. (2008) Quantum-limited metrology with product states. Physical Review A, 77 1: 012317-1-012317-15. doi:10.1103/PhysRevA.77.012317

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Author Boixo, Sergio
Datta, Animesh
Flammia, Steven T.
Shaji, Anil
Bagan, Emilio
Caves, Carlton M.
Title Quantum-limited metrology with product states
Journal name Physical Review A   Check publisher's open access policy
ISSN 1050-2947
1094-1622
Publication date 2008-01-15
Sub-type Article (original research)
DOI 10.1103/PhysRevA.77.012317
Open Access Status File (Publisher version)
Volume 77
Issue 1
Start page 012317-1
End page 012317-15
Total pages 15
Place of publication College Park, MD, United States
Publisher American Physical Society
Collection year 2009
Language eng
Abstract We study the performance of initial product states of n-body systems in generalized quantum metrology protocols that involve estimating an unknown coupling constant in a nonlinear k-body (kn) Hamiltonian. We obtain the theoretical lower bound on the uncertainty in the estimate of the parameter. For arbitrary initial states, the lower bound scales as 1/nk, and for initial product states, it scales as 1/nk−1/2. We show that the latter scaling can be achieved using simple, separable measurements. We analyze in detail the case of a quadratic Hamiltonian (k=2), implementable with Bose-Einstein condensates. We formulate a simple model, based on the evolution of angular-momentum coherent states, which explains the O(n−3/2) scaling for k=2; the model shows that the entanglement generated by the quadratic Hamiltonian does not play a role in the enhanced sensitivity scaling. We show that phase decoherence does not affect the O(n−3/2) sensitivity scaling for initial product states.
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: 2009 Higher Education Research Data Collection
School of Mathematics and Physics
 
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Citation counts: TR Web of Science Citation Count  Cited 49 times in Thomson Reuters Web of Science Article | Citations
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Created: Mon, 30 Mar 2009, 22:05:55 EST by Jo Hughes on behalf of School of Mathematics & Physics