Investigations of a two-mode atom-laser model - art. no. 053611

Atom lasers based on rf outcoupling from a trapped Bose-Einstein condensate can be described by a set of generalized, coupled Gross-Pitaevskii equatio ns (GPEs). If not only one but two radio frequencies are used for outcoupli ng, the atoms emerging from the trap have two different energies and the to tal wave function of the untrapped spin state is a coherent superposition w hich leads to a pulsed atomic beam. We present results for such a situation obtained from a one-dimensional GPE model for magnetically trapped Rb-87 i n the F = 1 state. The wave function of the atomic beam can be approximated by a sum of two Airy functions. In the limit bf weak coupling we calculate the intensity analytically.