Guided atom laser: transverse mode quality and longitudinal momentum distribution

François Vermersch (1) , Charlotte Fabre (1) , Pierrick Cheiney (1) , Giovanni Luca Gattobigio (1) , Renaud Mathevet (1) , David Guéry-Odelin (1)

1 LCAR - Laboratoire Collisions Agrégats Réactivité

We analyze the outcoupling of a matter wave into a guide by a time-dependent spilling of the atoms from an initially trapped Bose-Einstein condensate. This process yields intrinsically a breakdown of the adiabatic condition that triggers the outcoupling of the wave function. Our analysis of the time-dependent engineering and manipulation of condensates in momentum space in this context enables to work out the limits due to interactions in the mode quality of a guided atom laser. This study is consistent with recent experimental observations of low transverse excitations of guided atom lasers and suggests (i) an optimal strategy to realize such quasi-monomode guided atom lasers with, in addition, the lowest possible longitudinal velocity dispersion, or alternatively (ii) a strategy for engineering the atomic flux of the atom laser.

Domaines: Gaz Quantiques [cond-mat.quant-gas]

François Vermersch, Charlotte Fabre, Pierrick Cheiney, Giovanni Luca Gattobigio, Renaud Mathevet, et al.. Guided atom laser: transverse mode quality and longitudinal momentum distribution. 2011. ⟨hal-00612351v1⟩