Fig. 3: Trajectories of a soliton with an offset barrier.

The soliton undergoes centre of mass oscillations and interacts twice with a barrier that is offset 10 μm from the centre of the harmonic potential. a, b The results for the wide barrier where the soliton kinetic energy per atom at the barrier is E_k/k_B = 19.0 ± 0.5 nK. a The experimental image sequence, with the upper panel displaying the signal obtained by integrating across the final image. b The results of quasi-1D Gross–Pitaevskii equation (GPE) simulations, with the upper panel displaying the convolution of the final 1D density and the resolution of the imaging system. The barrier is indicated by the green line and the barrier power is held constant throughout each sequence to give a transmission of 0.5 at the first barrier interaction. c, d Similar results for the narrow barrier where the soliton kinetic energy per atom at the barrier is E_k/k_B = 2.5 ± 0.4 nK.