Relaxation of Inter-Landau-level excitations in the Quatized Hall Regime

Relaxation of collective plasmon inter-Landau-level excitation is determined by emission of LO-phonons or by Auger-like processes when this emission is suppressed off the magneto-phonon resonance conditions. The decay of "one-cyclotron" magneto-plasmons with wave-vectors near the roton minimum is studied under the condition of filling $\nu=1$. Some features of this relaxation should be helpful for the experimental detection of the magneto-rotons in a strongly correlated 2D electron gas.