Spatial distributions of the wavepackets associated with two stationary degenerate ground states for ϕ′ = 3, α = 0.1: (a) wavepackets associated with an ill kitten state with l = 0; (b) wavepackets corresponding to a kitten state with l = 1. Quantum transition between these degenerate ground states can be manipulated via ac-driven interchange of the wavepackets.