  Conservation of angular momentum depends on the existence of rotational
symmetry. However, even in systems where this symmetry is broken, flipping
between angular momentum eigenstates often requires an activation energy. Here
we discuss an example of superfluid flow in an azimuthally asymmetric toroidal
potential, which shows sustained oscillations between two different rotation
directions. The energy required to change the direction of rotation is taken
out of and temporarily restored into the rotational and intra-component
interaction energies of the system.
