Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Flexible generation of correlated photon pairs in different frequency
  ranges   The feasibility to generate correlated photon pairs at variable frequencies
is investigated. For this purpose, we consider the interaction of an
off-resonant laser field with a two-level system possessing broken inversion
symmetry. We show that the system generates non-classical photon pairs
exhibiting strong intensity-intensity correlations. The intensity of the
applied laser tunes the degree of correlation while the detuning controls the
frequency of one of the photons which can be in the THz-domain. Furthermore, we
observe the violation of a Cauchy-Schwarz inequality characterizing these
photons.

29
The categories of this paper are: funct-an
4
The categories of this paper are: cond-mat
7
The categories of this paper are: hep-th
5
The categories of this paper are: gr-qc
18
The categories of this paper are: econ
15
The categories of this paper are: nucl-ex
26
The categories of this paper are: bayes-an
9
The categories of this paper are: nlin
25
The categories of this paper are: patt-sol
0
The categories of this paper are: hep-ph
27
The categories of this paper are: comp-gas
16
The categories of this paper are: stat
30
The categories of this paper are: q-alg
12
The categories of this paper are: nucl-th
24
The categories of this paper are: dg-ga
34
The categories of this paper are: chem-ph