Oscillatory Behavior of a Superradiating System Coupled to Electron Reservoirs

We investigate a superradiating system coupled to external reservoirs. Under conditions where electrons tunneling at a rate $T$ act like an electron pump, we predict a novel phenomenon in the form of oscillations with a frequency $\omega \simeq \sqrt{2\Gamma T}$ that appears in the (photon) emission intensity, where $\Gamma$ is the spontaneous decay rate of a single two-level system. The effect, together with a strong enhancement of the superradiant peak, should be observable in semiconductor quantum wells in strong magnetic fields or in quantum dot arrays.