The evolution of a surface excitation in a two dimentional model is analyzed. I) It starts quadratically up to a spreading time tS. II) It follows an exponential behavior governed by a self-consistent Fermi Golden Rule. III) At longer times, the exponential is overrun by an inverse power law describing return processes governed by quantum diffusion. At this last transition time tRa survival collapse becomes possible, bringing the survival probability down by several orders of magnitude. We identify this strongly destructive interference as an antiresonance in the time domain.
Memory effects; Interference in time domain
