Determination of the fine structure constant with atom interferometry and Bloch oscillations

The fine structure constant α sets the scale of the electromagnetic interaction so it can be determined in different domains of physics. As α is dimensionless, it does not depend on any unit system. Hence this allows the comparison of various accurate determinations which constitutes an interesting test of the consistency of physics. The most precise determination of α comes from the measurement of the electron magnetic moment anomaly ae, but this determination is strongly dependent on QED calculations. There are many reasons to realize an other determination of α. (i) The CODATA value is determined mainly by only one value of α, this is a true weakness. (ii) The comparison of α(ae) with another measurement which is weakly dependent on QED provides an accurate test of QED. (iii) Assuming QED is exact, a determination of α with the same uncertainty as α(ae) gives an upper limit upon a possible internal electron structure. We report a new measurement of the atomic recoil using atom interferometry and Bloch oscillations (BO) in a vertical accelerated optical lattice. Such a measurement yields to a determination of h/m (m is the mass of the atom) which can be used to obtain a value of the fine structure constant following the equation: