Multipath interferometer with ultracold atoms trapped in an optical lattice

Year: 2013

Authors: Chwedenczuk J., Piazza F., Smerzi A.

Autors Affiliation: Faculty of Physics, University of Warsaw, ul. Hoża 69, PL-00-681 Warszawa, Poland;
Physik Department, Technische Universität München, D-85747 Garching, Germany;
QSTAR Center for Quantum Science and Technology, CNR-INO and LENS, Largo Enrico Fermi 2, I-50125 Arcetri, Italy

Abstract: We study an ultracold gas of N bosons trapped in a one-dimensional M-site optical lattice perturbed by a spatially dependent potential gx(j), where the unknown coupling strength g is to be estimated. We find that the measurement uncertainty is bounded by Delta g alpha 1/N(M-j-1). For a typical case of a linear potential, the sensitivity improves as M-1, which is a result of multiple interferences between the sites, an advantage of multipath interferometers over two-mode setups. Next, we calculate the estimation sensitivity for a specific measurement where, after the action of the potential, the particles are released from the lattice and form an interference pattern. If the parameter is estimated by a least-squares fit of the average density to the interference pattern, the sensitivity still scales like M-1 for linear potentials. We finally discuss the role of useful entanglement of the initial state in the lattice to beat the shot-noise limit. DOI: 10.1103/PhysRevA.87.033607

Journal/Review: PHYSICAL REVIEW A

Volume: 87 (3)      Pages from: 33607-1  to: 33607-10

More Information: We thank Alessio Recati for useful remarks and Markus Oberthaler for pointing out the possibility of measuring the shape of nonlinear potentials. J.Ch. acknowledges the Foundation for Polish Science International TEAM Program cofinanced by the EU European Regional Development Fund and the support of National Science Center Grant No. DEC-2011/03/D/ST2/00200. F.P. acknowledges support by the Alexander Von Humboldt Foundation. A.S. acknowledges the support of the EU-STREP Project QIBEC.
KeyWords: Standard Quantum Limit; Entanglement; Precision; States
DOI: 10.1103/PhysRevA.87.033607

Citations: 16
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