Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Integral representation of the scalar propagators on the de Sitter
  expanding universe   A new type of integral representation is proposed for the propagators of the
massive Klein-Gordon field minimally coupled to the gravity of the de Sitter
expanding universe. This representation encapsulates the effects of the
Heaviside step functions of the Feynman propagators making possible for the
first time the calculation of Feynman diagrams involving scalar particles on
this background. In order to convince that, a simple example is given outlining
the amplitudes in the second order of perturbations of the Compton effect in
the de Sitter scalar quantum electrodynamics.

36
The categories of this paper are: cmp-lg
6
The categories of this paper are: astro-ph
8
The categories of this paper are: hep-ex
7
The categories of this paper are: hep-th
23
The categories of this paper are: solv-int
35
The categories of this paper are: mtrl-th
13
The categories of this paper are: quant-ph
21
The categories of this paper are: adap-org
32
The categories of this paper are: atom-ph
3
The categories of this paper are: physics
9
The categories of this paper are: nlin
0
The categories of this paper are: hep-ph
30
The categories of this paper are: q-alg
26
The categories of this paper are: bayes-an
25
The categories of this paper are: patt-sol
31
The categories of this paper are: ao-sci