Issue
EPL
Volume 85, Number 3, February 2009
Article Number 31001
Number of page(s) 5
Section The Physics of Elementary Particles and Fields
DOI http://dx.doi.org/10.1209/0295-5075/85/31001
Published online 22 January 2009
EPL, 85 (2009) 31001
DOI: 10.1209/0295-5075/85/31001

Quantitative non-contact dynamic Casimir force measurements

G. Jourdan1, 2, 3, A. Lambrecht3, F. Comin4 and J. Chevrier1, 2, 4

1   Institut Néel, CNRS-UJF - BP 166, 38042, Grenoble Cedex 9, France, EU
2   Université Joseph Fourier - BP 53, 38041, Grenoble Cedex 9, France, EU
3   Laboratoire Kastler Brossel, CNRS-ENS-UPMC - 4 Place Jussieu, 75252 Cedex 05, France, EU
4   ESRF - 6 rue Jules Horowitz, BP 220, 38043, Grenoble Cedex, France, EU

guillaume.jourdan@crans.org

received 15 December 2008; accepted in final form 6 January 2009; published February 2009
published online 22 January 2009

Abstract
We show that the Casimir force (CF) gradient can be measured with no contact involved. Results of the CF measurement with systematic uncertainty of $3{\%}$ are presented for the distance range of 100$\hbox{--} $600 nm. The statistical uncertainty is shown to be due to the thermal fluctuations of the force probe. The corresponding signal-to-noise ratio equals unity at the distance of 600 nm. Direct contact between surfaces used in most previous studies to determine absolute distance separation is here precluded. Use of direct contact to identify the origin of distances is a severe limitation for studies of the CF on structured surfaces as it deteriorates irreversibly the studied surface and the probe. This force machine uses a dynamical method with an inserted gold sphere probe glued to a lever. The lever is mechanically excited at resonant frequency in front of a chosen sample. The absolute distance determination is achieved to be possible, without any direct probe/sample contact, using an electrostatic method associated to a real time correction of the mechanical drift. The positioning shift uncertainty is as low as 2 nm. Use of this instrument to probe a very thin film of gold (10 nm) reveals important spatial variations in the measurement.

PACS
12.20.Fv - Quantum electrodynamics: Experimental tests.
42.50.Lc - Quantum fluctuations, quantum noise, and quantum jumps.
03.70.+k - Theory of quantized fields.

© EPLA 2009