Macroscopic quantum self-trapping

In quantum mechanics, macroscopic quantum self-trapping is when two Bose–Einstein condensates weakly linked by an energy barrier which particles can tunnel through, nevertheless end up with a higher average number of bosons on one side of the junction than the other. The junction of two Bose–Einstein condensates is mostly analogous to a Josephson junction, which is made of two superconductors linked by a non-conducting barrier.

Source: Wikipedia — Macroscopic quantum self-trapping (CC BY-SA 4.0)