Induced charge-density oscillation under a quantizing magnetic field and intense terahertz radiation

The time-dependent Schro¨dinger equation for a two-dimensional electron gas in a strong magnetic field and an intense terahertz laser field is solved by constructing unitary transformations. We calculate the chargedensity fluctuation under a weak probing potential. It is found that the induced charge density oscillates rapidly in time with two characteristic frequencies, the cyclotron frequency and the laser frequency.