Confinement of matter-wave solitons on top of a pedestal-shaped potential

Reflection of wave packets from downward potential steps and attractive potentials, known as a quantum reflection, has been explored for bright matter-wave solitons with the main emphasis on the possibility to trap them on top of a pedestal-shaped potential. In numerical simulations, we observed that moving solitons return from the borders of the potential and remain trapped for a sufficiently long time. The shuttle motion of the soliton is accompanied by shedding some amount of matter at each reflection from the borders of the trap, thus reducing its norm. The one- and two- soliton configurations are considered. A discontinuous jump of trajectories of colliding solitons has been discussed. The time-shift observed in a step-like decay of the moving soliton's norm in the two-soliton configuration is linked to the trajectory jump phenomenon. The obtained results can be of interest for the design of new soliton experiments with Bose-Einstein condensates.
Comment: 4 pages, 5 figures