  Using Maxwell-Bloch equations it has been shown how the superradiance can
lead to amplification and gain at a frequency much larger than the pumping
frequency. This remarkable effect has been examined in terms of a simpler model
involving two coupled oscillators with one of them paramet- rically driven. We
show that this coupled oscillator model has a hidden parity-time (PT) symmetry
for QASER, we thus bring PT symmetry to the realm of parametrically coupled
resonators. More- over, we find that the QASER gain arises from the broken PT
symmetry phase. We then quantize the simplified version of the QASER using
quantum Langevin equations. The quantum description enables us to understand
how the system starts from quantum fluctuations.
