title: Scattering length instability in dipolar Bose-Einstein condensates.
abstract: We predict a new kind of instability in a Bose-Einstein condensate composed of dipolar particles. Namely, a comparatively weak dipole moment can produce a large, negative two-body scattering length that can collapse the Bose-Einstein condensate. To verify this effect, we validate mean-field solutions to this problem using exact, diffusion Monte Carlo methods. We show that the diffusion Monte Carlo energies are reproduced accurately within a mean-field framework if the variation of the s-wave scattering length with the dipole strength is accounted for properly.
authors.affiliation: JILA, NIST and Department of Physics, University of Colorado, Boulder, CO 80309-0440, USA.
authors.forename: D C E
authors.initials: DC
authors.lastname: Bortolotti
authors.forename: S
authors.initials: S
authors.lastname: Ronen
authors.forename: J L
authors.initials: JL
authors.lastname: Bohn
authors.forename: D
authors.initials: D
authors.lastname: Blume