Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Statistical properties of twin beams generated in spontaneous parametric
  downconversion   Measurement of photon-number statistics of fields composed of photon pairs
generated in spontaneous parametric downcoversion pumped by strong ultrashort
pulses is described. Final detection quantum efficiencies, noises as well as
possible loss of one or both photons from a pair are taken into account.
Measured data provided by an intensified single-photon CCD camera are analyzed
along the developed model. The joint signal-idler photon-number distribution is
obtained using the expectation maximization algorithm. Covariance of the signal
and idler photon-numbers equals 80 %. Statistics of the generated photon pairs
are identified to be Poissonian in our case. Distribution of the integrated
intensities of the signal and idler fields shows strong correlations between
the fields. Negative values of this distribution occurring in some regions
clearly demonstrate a nonclassical character of the light composed of photon
pairs.

18
The categories of this paper are: econ
20
The categories of this paper are: acc-phys
0
The categories of this paper are: hep-ph
9
The categories of this paper are: nlin
14
The categories of this paper are: math-ph
22
The categories of this paper are: chao-dyn
2
The categories of this paper are: math
17
The categories of this paper are: q-fin
30
The categories of this paper are: q-alg
32
The categories of this paper are: atom-ph
35
The categories of this paper are: mtrl-th
37
The categories of this paper are: supr-con
26
The categories of this paper are: bayes-an
8
The categories of this paper are: hep-ex
5
The categories of this paper are: gr-qc
29
The categories of this paper are: funct-an