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Cadoret, Malo; de Mirandes, Estefania; Cladé, Pierre; Guellati-Khélifa, Saïda; Schwob, Catherine; Nez, François; Julien, Lucile; Biraben, François
The European physical journal. ST, Special topics, 2008, Letnik: 163Journal Article
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.
