Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Statistical Mechanics of gravitating systems in static and cosmological
  backgrounds   This pedagogical review addresses several issues related to statistical
description of gravitating systems in both static and expanding backgrounds,
focusing on the latter. After briefly reviewing the results for the static
background, I describe the key issues and recent progress in the context of
gravitational clustering of collision-less particles in an expanding universe.
The questions addressed include: (a) How does the power injected into the
system at a given wave number spread to smaller and larger scales? (b) How does
the power spectrum of density fluctuations behave asymptotically at late times?
(c) What are the universal characteristics of gravitational clustering that are
independent of the initial conditions and manifest at the late time evolution
of the system? The review is intended for non cosmologists and will be of
interest to people working in fluid mechanics, non linear dynamics and
condensed matter physics.

33
The categories of this paper are: plasm-ph
21
The categories of this paper are: adap-org
17
The categories of this paper are: q-fin
31
The categories of this paper are: ao-sci
0
The categories of this paper are: hep-ph
37
The categories of this paper are: supr-con
20
The categories of this paper are: acc-phys
10
The categories of this paper are: q-bio
36
The categories of this paper are: cmp-lg
5
The categories of this paper are: gr-qc
16
The categories of this paper are: stat
25
The categories of this paper are: patt-sol
1
The categories of this paper are: cs
15
The categories of this paper are: nucl-ex
27
The categories of this paper are: comp-gas
13
The categories of this paper are: quant-ph