title: Controlling condensate collapse and expansion with an optical Feshbach resonance.
abstract: We demonstrate control of the collapse and expansion of an (88)Sr Bose-Einstein condensate using an optical Feshbach resonance near the (1)S(0)-(3)P(1) intercombination transition at 689 nm. Significant changes in dynamics are caused by modifications of scattering length by up to ± 10a(bg), where the background scattering length of (88)Sr is a(bg) = -2a(0) (1a(0) = 0.053 nm). Changes in scattering length are monitored through changes in the size of the condensate after a time-of-flight measurement. Because the background scattering length is close to zero, blue detuning of the optical Feshbach resonance laser with respect to a photoassociative resonance leads to increased interaction energy and a faster condensate expansion, whereas red detuning triggers a collapse of the condensate. The results are modeled with the time-dependent nonlinear Gross-Pitaevskii equation.
authors.affiliation: Department of Physics and Astronomy, Rice University, Houston, Texas 77251, USA.
authors.forename: Mi
authors.initials: M
authors.lastname: Yan
authors.affiliation: Department of Physics and Astronomy, Rice University, Houston, Texas 77251, USA.
authors.forename: B J
authors.initials: BJ
authors.lastname: DeSalvo
authors.affiliation: Department of Physics and Astronomy, Rice University, Houston, Texas 77251, USA.
authors.forename: B
authors.initials: B
authors.lastname: Ramachandhran
authors.affiliation: Department of Physics and Astronomy, Rice University, Houston, Texas 77251, USA.
authors.forename: H
authors.initials: H
authors.lastname: Pu
authors.affiliation: Department of Physics and Astronomy, Rice University, Houston, Texas 77251, USA.
authors.forename: T C
authors.initials: TC
authors.lastname: Killian