“…On the other hand, it is well-known that the BEC governed by a Gross-Pitaevskii equation (GPE) without external potential is an integrable system and the integrability could be easily broken by external potentials of different forms [11]. So previously, only few analytical works concern exact solutions of the system, where one-dimensional (1D) stationary systems with some simple potentials are treated, such as the infinite or finite square-wells [12,13,14,15], the step-potentials [16], δ or δ comb potentials [17,18,19], linear ramp potential [20,21] and optical lattice potentials [22,23]. Under some rigorous conditions on the interaction intensities or external potentials, several exact nonstationary-state solutions were constructed [24,25], including the exact soliton solutions [26,27,28,29,30].…”