Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the van Cittert - Zernike theorem for intensity correlations and its
  applications   A reciprocal relationship between the autocovariance of the light intensity
in the source plane and in the far-field detector plane is presented in a form
analogous to the classical van Cittert - Zernike theorem, but involving
intensity correlation functions. A "classical" version of the reciprocity
relationship is considered first, based on the assumption of circular Gaussian
statistics of the complex amplitudes in the source plane. The result is
consistent with the theory of Hanbury Brown - Twiss interferometry, but it is
shown to be also applicable to estimation of the source size or the spatial
resolution of the detector from the noise power spectrum of flat-field images.
An alternative version of the van Cittert - Zernike theorem for intensity
correlations is then derived for a quantized electromagnetic beam in a coherent
state, which leads to Poisson statistics for the intrinsic intensity of the
beam.

14
The categories of this paper are: math-ph
33
The categories of this paper are: plasm-ph
16
The categories of this paper are: stat
2
The categories of this paper are: math
34
The categories of this paper are: chem-ph
28
The categories of this paper are: alg-geom
29
The categories of this paper are: funct-an
9
The categories of this paper are: nlin
11
The categories of this paper are: hep-lat
22
The categories of this paper are: chao-dyn
37
The categories of this paper are: supr-con
17
The categories of this paper are: q-fin
21
The categories of this paper are: adap-org
23
The categories of this paper are: solv-int
31
The categories of this paper are: ao-sci
0
The categories of this paper are: hep-ph