We study a nonlinear Schroedinger equation arising in the mean-field
description of dipolar quantum gases. Under the assumption of sufficiently
strong dipolar interactions, the existence of standing waves, and hence
solitons, is proved together with some of their properties. This gives a
rigorous argument for the possible existence of solitary waves in Bose-Einstein
condensates, which originate solely due to the dipolar interaction between the
particles.Comment: Minor modifications; more explanations added. To appear in Physica