Femtosecond dynamics of inter-Landau level excitations of a two-dimensional electron gas in the quantum Hall regime

We use degenerate four-wave mixing to investigate the dynamics of electron–hole pairs interacting with magnetoplasmon excitations of a two-dimensional electron gas (2DEG) in the quantum Hall effect regime. We observe a strong coupling between Landau levels induced by the magnetoplasmon interactions, leading to a transfer of our signal strength to the lowest Landau level, as well as strong non-Markovian effects. These observations are interpreted within a model taking into account the many body Hamiltonian for the 2DEG system.