First observation of feshbach resonances at very low magnetic field in a 133Cs fountain.

H. Marion (1) , S. Bize (1) , L. Cacciapuoti (1) , D. Chambon (1) , F. Pereira Dos Santos (1) , G. Santarelli (1) , P. Wolf (1) , A. Clairon (1) , A. Luiten (2) , M. Tobar (2) , S. Kokkelmans (3) , C. Salomon (3)

1 SYRTE - Systèmes de Référence Temps Espace
2 UWA - The University of Western Australia
3 LKB (Lhomond) - Laboratoire Kastler Brossel

One of the main limitations of cesium atomic fountains has been the cold collision frequency shift. By using a method based on a transfer of population by adiabatic passage allowing to prepare cold atomic samples with a well defined ratio of atomic density as well as atom number the collisional shift is controlled at the 10E-3 of its value. A calibration of Zeeman sub-states contribution to the clock shift as a function of the field has been performed. Feshbach resonances have been observed for the first time at very low magnetic field and with a very good resolution. A Monte Carlo simulation has been performed and could fit properly some of experimental data. This constrains some parameters of the theory of collisions.

Keywords: Atomic fountain; cryogenic oscillator; frequency measurement; cold collisions; adiabatic passage; Feshbach resonance

Domains: Atomic Physics [physics.atom-ph]; Other [cond-mat.other]

H. Marion, S. Bize, L. Cacciapuoti, D. Chambon, F. Pereira Dos Santos, et al.. First observation of feshbach resonances at very low magnetic field in a 133Cs fountain.. 2004. ⟨hal-00002196v1⟩