publication . Article . Preprint . Other literature type . 2009

Entanglement, Nonlinear Dynamics, and the Heisenberg Limit

Pezzé, Luca; Smerzi, A.;
Open Access English
  • Published: 10 Mar 2009
  • Publisher: HAL CCSD
  • Country: France
Abstract
We show that the quantum Fisher information provides a sufficient condition to recognize multi-particle entanglement in a $N$ qubit state. The same criterion gives a necessary and sufficient condition for sub shot-noise phase sensitivity in the estimation of a collective rotation angle $\theta$. The analysis therefore singles out the class of entangled states which are {\it useful} to overcome classical phase sensitivity in metrology and sensors. We finally study the creation of useful entangled states by the non-linear dynamical evolution of two decoupled Bose-Einstein condensates or trapped ions.
Subjects
free text keywords: [PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], Quantum Physics, Condensed Matter - Other Condensed Matter, General Physics and Astronomy
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d'Optique, Campus Polytechnique, F-91127 Palaiseau

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pj 0 and Pjpj ¼ 1). The QFI can always be saturated

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