Precise determination of h/mRb using Bloch oscillations and atomic interferometry: A mean to deduce the fine structure constant

M. Cadoret; E. de Mirandes; P. Cladé; S. Guellati-Khélifa; C. Schwob; F. Nez; L. Julien; F. Biraben

doi:10.1140/epjst/e2008-00813-9

EPJ

Precise determination of h/m_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 Cedex 05, France
² INM, Conservatoire National des Arts et Métiers, 61 rue Landy, 93210 La plaine Saint-Denis, France

Abstract

We use Bloch oscillations to transfer coherently many photon momenta to atoms. Then we can measure accurately the ratio h/m_Rb and deduce the fine structure constant α. The velocity variation due to the Bloch oscillations is measured thanks to Raman transitions. In a first experiment, two Raman π pulses are used to select and measure a very narrow velocity class. This method yields to a value of the fine structure constant α^-1= 137.03599884(91) with a relative uncertainty of about 6.6 ppb. More recently we use an atomic interferometer consisting in two pairs of π/2 pulses. We present here the first results obtained with this method.