Eur. Phys. J. D 38, 353-365 (2006)
https://doi.org/10.1140/epjd/e2006-00015-5

Atom interferometry measurement of the electric polarizability of lithium

Laboratoire Collisions Agrégats Réactivité, IRSAMC, Université Paul Sabatier and CNRS UMR 5589, 118 route de Narbonne, 31062 Toulouse Cedex, France

Corresponding author: ^a jacques.vigue@irsamc.ups-tlse.fr

Received: 29 July 2005
Revised: 2 December 2005
Published online: 17 January 2006

Abstract

Using an atom interferometer, we have measured the static electric polarizability of ⁷Li α=(24.33 ±0.16)×10^-30  m³ = 164.2±1.1 atomic units with a 0.66% uncertainty. Our experiment, which is similar to an experiment done on sodium in 1995 by Pritchard and co-workers, consists in applying an electric field on one of the two interfering beams and measuring the resulting phase-shift. With respect to Pritchard's experiment, we have made several improvements which are described in detail in this paper: the capacitor design is such that the electric field can be calculated analytically; the phase sensitivity of our interferometer is substantially better, near 16 mrad/; finally our interferometer is species selective so that impurities present in our atomic beam (other alkali atoms or lithium dimers) do not perturb our measurement. The extreme sensitivity of atom interferometry is well illustrated by our experiment: our measurement amounts to measuring a slight increase Δv of the atom velocity v when it enters the electric field region and our present sensitivity is sufficient to detect a variation Δv/v ≈6 ×10^-13.