Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Green Function for Metric Perturbations due to Cosmological Density
  Fluctuations   We study scalar perturbations to a Robertson-Walker cosmological metric in
terms of a pseudo-Newtonian potential, which emerges naturally from the
solution of the field equations. This potential is given in terms of a Green
function for matter density fluctuations of arbitrary amplitude whose time and
spatial dependence are assumed known. The results obtained span both the
linearized and Newtonian limits, and do not explicitly depend on any kind of
averaging procedure, but make the valid assumption that the global expansion
rate is that of a Friedmann-Robertson-Walker model. In addition, we discuss the
similarity to diffusive processes in the evolution of the potential, and
possible applications.

8
The categories of this paper are: hep-ex
31
The categories of this paper are: ao-sci
21
The categories of this paper are: adap-org
4
The categories of this paper are: cond-mat
15
The categories of this paper are: nucl-ex
7
The categories of this paper are: hep-th
24
The categories of this paper are: dg-ga
37
The categories of this paper are: supr-con
16
The categories of this paper are: stat
10
The categories of this paper are: q-bio
36
The categories of this paper are: cmp-lg
14
The categories of this paper are: math-ph
25
The categories of this paper are: patt-sol
11
The categories of this paper are: hep-lat
1
The categories of this paper are: cs
23
The categories of this paper are: solv-int