Photoassociative frequency shift in a quantum degenerate gas - art. no. 053410

A light-induced frequency shift is observed in single-photon photoassociati ve spectra of magnetically trapped, quantum degenerate Li-7. The shift is a manifestation of the coupling between the threshold continuum scattering s tates and discrete bound levels in the excited-state molecular potential in duced by the photoassociation laser. The frequency shift is observed to be linear in the laser intensity with a measured proportionality constant that is in good agreement with theoretical predictions. This phenomenon has imp ortant implications for a scheme to alter the interactions between atoms in a Bose-Einstein condensate using photoassociation resonances.