Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Lasing at arbitrary frequencies with atoms with broken inversion
  symmetry and an engineered electromagnetic environment   With the purpose to devise a novel lasing scheme, we consider a two level
system with both a transversal and longitudinal coupling to the electromagnetic
field. If the longitudinal coupling is sufficiently strong, multi-photon
transitions become possible. We assume furthermore that the electromagnetic
environment has a spectrum with a single sharp resonance, which serves as a
lasing cavity. Additionally, the electromagnetic environment should have a very
broad resonance around a frequency which differs form the sharp resonance. We
use the polaron transformation and derive a rate equation to describe the
dynamics of such system. We find that lasing at the frequency of the sharp mode
is possible, if the energy difference of the atomic transition is similar to
the sum of the frequencies of both peaks in the spectral function. This allows
for the creation of lasing over a large frequency range and may in perspective
enable THz lasing at room temperature.

15
The categories of this paper are: nucl-ex
9
The categories of this paper are: nlin
34
The categories of this paper are: chem-ph
0
The categories of this paper are: hep-ph
10
The categories of this paper are: q-bio
18
The categories of this paper are: econ
22
The categories of this paper are: chao-dyn
8
The categories of this paper are: hep-ex
27
The categories of this paper are: comp-gas
30
The categories of this paper are: q-alg
3
The categories of this paper are: physics
5
The categories of this paper are: gr-qc
19
The categories of this paper are: eess
36
The categories of this paper are: cmp-lg
12
The categories of this paper are: nucl-th
1
The categories of this paper are: cs