A promising method for the measurement of the local acceleration of gravity using Bloch oscillations of ultracold atoms in a vertical standing wave

¹ Laboratoire Kastler-Brossel, École Normale Supérieure, CNRS, UPMC 4 place Jussieu, 75252 Paris Cedex 05, France
² CNAM-INM, Conservatoire National des Arts et Métiers 292 rue Saint Martin, 75141 Paris Cedex 03, France

Received: 17 March 2005
Accepted: 11 July 2005

Abstract

An obvious determination of the local acceleration of gravity g can be deduced from the measurement of the velocity of falling atoms using a π-π pulses sequence of stimulated Raman transitions. By using a vertical standing wave to hold atoms against gravity, we expect to improve the relative accuracy by increasing the upholding time in the gravity field and to minimize the systematic errors induced by inhomogeneous fields, owing to the very small spatial amplitude of the atomic center-of-mass wavepacket periodic motion. We also propose to use such an experimental setup nearby a Watt balance. By exploiting the (h is the Planck constant) dependence of the Bloch frequency, this should provide a way to link a macroscopic mass to an atomic mass.