Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Hidden PT Symmetry and quantization of coupled-oscillators model of
  QASER   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.

26
The categories of this paper are: bayes-an
14
The categories of this paper are: math-ph
20
The categories of this paper are: acc-phys
27
The categories of this paper are: comp-gas
6
The categories of this paper are: astro-ph
10
The categories of this paper are: q-bio
2
The categories of this paper are: math
29
The categories of this paper are: funct-an
33
The categories of this paper are: plasm-ph
9
The categories of this paper are: nlin
22
The categories of this paper are: chao-dyn
15
The categories of this paper are: nucl-ex
3
The categories of this paper are: physics
16
The categories of this paper are: stat
23
The categories of this paper are: solv-int
35
The categories of this paper are: mtrl-th