Stuttgart 2012 – scientific programme
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SYQM: Symposium Quantum Limited Measurement: Applications in Metrology, Biology and Solid State Research
SYQM 2: Quantum limited measurement applications 2
SYQM 2.6: Talk
Friday, March 16, 2012, 15:45–16:00, V47.01
Sub shot-noise interferometry from measurements of the one-body density — Jan Chwedenczuk1,2, •Philipp Hyllus1,3, Francesco Piazza1,4, and Augusto Smerzi1,5 — 1INO-CNR BEC Center and Dipartimento di Fisica, Università di Trento, 38123 Povo, Italy — 2Faculty of Physics, University of Warsaw, ul. Hȯza 69, 00-681 Warsaw, Poland — 3Department of Theoretical Physics, The University of the Basque Country, P.O. Box 644, E-48080 Bilbao, Spain — 4Physik Department T34,Technische Universität München, James-Franck-Straße, 85747 Garching, Germany — 5INO-CNR and LENS, 50125 Firenze, Italy
We show that a sub shot-noise sensitivity – associated with the quantum correlations present in the state entering the interferometer – can be achieved with particle-position measurements using a new phase estimator which does not require any knowledge about these correlations, and is based on the single-body density. For the case of the estimation of the relative phase θ between two interfering wave-packets we demonstrate that the sensitivity can scale as Δ2θ∝ N−1.33 with the total number of particles N when phase-squeezed states are used. The necessary amount of squeezing could be created using a Bose-Einstein Condensate trapped in a double-well potential, and we argue that even with finite detection efficiency/resolution, sub shot-noise sensitivity can be preserved.