Combination of Bloch Oscillations with a Ramsey-Bordé Interferometer: New Determination of the Fine Structure Constant

We report a new experimental scheme which combines atom interferometry with Bloch oscillations to provide a new measurement of the ratio h/mRb. By using Bloch oscillations, we impart to the atoms up to 1600 recoil momenta and thus we improve the accuracy on the recoil velocity measurement. The deduced value of h/mRb leads to a new determination of the fine structure constant α^-1=137.035 999 45 (62) with a relative uncertainty of 4.6×10^-9. The comparison of this result with the value deduced from the measurement of the electron anomaly provides the most stringent test of QED.