Precise determination of h/mRb using Bloch oscillations and atomic interferometry: a mean to deduce the fine structure constant
Abstract
We use Bloch oscillations to transfer coherently many photon momenta to atoms. Then we can measure accurately the ratio h/mRb 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 π 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.
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