Wave tails in time-dependent backgrounds

It is well known that waves propagating under the influence of a scattering potential develop ``tails.'' However, the study of late-time tails has so far been restricted to time-independent backgrounds. In this paper, we explore the late-time evolution of spherical waves propagating under the influence of a time-dependent scattering potential. It is shown that the tail structure is modified due to the temporal dependence of the potential. The analytical results are confirmed by numerical calculations.