Stability of quasi-two-dimensional Bose-Einstein condensates with dominant dipole-dipole interactions

We consider quasi-two-dimensional atomic or molecular Bose-Einstein condensates with both contact and dipole-dipole interactions. It is shown that as a consequence of the dimensional reduction, and within mean-field theory, the condensates do not develop unstable excitation spectra, even when the dipole-dipole interaction completely dominates the contact interaction.