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

Malo Cadoret (1) , Estefania de Mirandes (1) , Pierre Cladé (1) , Saïda Guellati-Khélifa (2) , Catherine Schwob (1) , François Nez (1) , Lucile Julien (1) , François Biraben (1)

1 LKB (Jussieu) - Laboratoire Kastler Brossel
2 LCM - Laboratoire commun de métrologie LNE-CNAM

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 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.

Domaines: Physique Atomique [physics.atom-ph]

Malo Cadoret, Estefania de Mirandes, Pierre Cladé, Saïda Guellati-Khélifa, Catherine Schwob, et al.. Precise determination of h/m_Rb using Bloch oscillations and atomic interferometry: a mean to deduce the fine structure constant. The European Physical Journal. Special Topics, 2008, 163, pp.101. ⟨10.1140/epjst/e2008-00813-9⟩. ⟨hal-00322765⟩