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Issue Eur. Phys. J. Special Topics
Volume 163, October I 2008
Atomic Clocks and Fundamental Constants
Page(s) 101 - 111
DOI 10.1140/epjst/e2008-00813-9
Published online 25 October 2008

Eur. Phys. J. Special Topics 163, 101-111 (2008)
DOI: 10.1140/epjst/e2008-00813-9

Precise determination of ${h/m_{\rm Rb}}$ using Bloch oscillations and atomic interferometry: A mean to deduce the fine structure constant

M. Cadoret1, E. de Mirandes1, P. Cladé1, S. Guellati-Khélifa2, C. Schwob1, F. Nez1, L. Julien1 and F. Biraben1

1  Laboratoire Kastler Brossel, ENS, CNRS, UPMC, 4 place Jussieu, 75252 Paris Cedox 05, France
2  INM, Conservatoire National des Arts et Métiers, 61 rue Landy, 93210 La plaine Saint-Denis, France

biraben@spectro.jussieu.fr

Abstract
We use Bloch oscillations to transfer coherently many photon momenta to atoms. Then we can measure accurately the ratio ${h/m_{\rm Rb}}$ and deduce the fine structure constant $\alpha$. The velocity variation due to the Bloch oscillations is measured thanks to Raman transitions. In a first experiment, two Raman $\pi$ pulses are used to select and measure a very narrow velocity class. This method yields to a value of the fine structure constant $\alpha^{-1}= 137.035\,998\,84\,(91)$ with a relative uncertainty of about 6.6 ppb. More recently we use an atomic interferometer consisting in two pairs of $\pi$/2 pulses. We present here the first results obtained with this method.



© EDP Sciences, Springer-Verlag 2008


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