where v(ω) is an interaction function, n0 represents an integer number of discrete 3PB states, ω is the frequency, κ0 is the electron hopping amplitude between adjacent 3PB states, and k is a continuous variable in the range 0 < k < π. By applying multiple-scale asymptotic analysis in the Van Hove λ 2 t limit, an assumed infinitesimally small coupling λ of a decaying discrete 3PB state reveals discrete states embedded in the continuum acting as transient trapping states that slow down the decay (Fig. ).