Quantum tunnelling is a phenomenon of non-equilibrium quantum dynamics and its detailed process is largely unexplored. We report the experimental observation of macroscopic quantum tunnelling of Bose–Einstein condensate in a hybrid trap. By exerting a non-adiabatic kick to excite a collective rotation mode of the trapped condensate, a periodic pulse train, which remains as condensate, is then out-coupled by quantum tunnelling. This non-equilibrium dynamics is analogue to tunnelling ionization. The imaged tunnelling process shows the splitting of matter wave packet by the potential barrier. The controversial “tunnelling time" question is found inadequate, from the point of view of wave propagation. The realized matter wave pulse train can also be a passive pulsed atom laser for atom interferometer applications.

量子隧穿是一种非平衡量子动力​​学现象，其详细过程在很大程度上尚待探索。我们报告了在混合阱中宏观玻色-爱因斯坦凝聚物量子隧穿的实验观察。通过施加非绝热的反冲来激发被捕集的凝结水的集体旋转模式，然后通过量子隧穿将保持为凝结水的周期性脉冲串耦合出去。这种非平衡动力学类似于隧穿电离。成像隧道过程显示了势垒对物质波包的分裂。从波传播的角度来看，有争议的“隧道时间”问题被认为是不充分的，所实现的物质波脉冲列也可以是用于原子干涉仪应用的无源脉冲原子激光器。