Determination of the fine structure constant based on Bloch oscillations of ultracold atoms in a vertical optical lattice -: art. no. 033001

We report an accurate measurement of the recoil velocity of Rb-87 atoms based on Bloch oscillations in a vertical accelerated optical lattice. We transfer about 900 recoil momenta with an efficiency of 99.97% per recoil. A set of 72 measurements of the recoil velocity, each one with a relative uncertainty of about 33 ppb in 20 min integration time, leads to a determination of the fine structure constant alpha with a statistical relative uncertainty of 4.4 ppb. The detailed analysis of the different systematic errors yields to a relative uncertainty of 6.7 ppb. The deduced value of alpha(-1) is 137.035 998 78(91).