Non-adiabatic population transfer in coupled bosonic systems

We study nonlinear Landau-Zener tunnelling in discrete Gross-Pitaevskii systems accounting for finite energy-level shifts generated by broadened pulse shapes in the non-adiabatic regime. Under these conditions, the tunnelling dynamics is generally sensitive to the pulse arrival time, however, we show that through variation of the pulse shape one can recover a case of rapid high fidelity population transfer independent of the pulse arrival time. We demonstrate how population transfer is possible in two-mode and three-mode systems. In large systems, we expect that population transfer between a pair of modes can be achieved through the application of a sequence of pulses that select pairs of neighbouring modes at each step.