Existence and nonexistence of wave operators for time-decaying harmonic oscillators

Controlled time-decaying harmonic potentials decelerate the velocity of the charged particle but the particle never be trapped by this harmonic potentials. This physical phenomena changes threshold between the short range class of potential and long-range class of potential in the sense of the existence of physical wave operators. In this paper, we reveal such a threshold is $1/(1-\lambda)$ for some $0\leq \lambda<1/2$ , which is determined by the mass of the particle and a coefficient of harmonic potential.