Symmetry breaking in the collisions of double channel BEC solitons

We investigate an attractive Bose-Einstein condensate in two coupled one dimensional channels. In this system, a stable double channel soliton can form. It is symmetric for small interaction parameters but asymmetric for large ones. We study this symmetry breaking phenomenon. Next, we investigate the dynamics of symmetric double channel soliton collisions. For sufficiently strong interactions we observe spontaneous symmetry breaking during the collision. Approximate considerations based on two different methods, Bogoliubov and variational, are used to describe this effect. The results are largely compatible.