Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Equation of State for a van der Waals Universe during Reissner-Nordstrom
  Expansion   In a previous work [E.M. Prodanov, R.I. Ivanov, and V.G. Gueorguiev,
Reissner-Nordstrom Expansion, Astroparticle Physics 27 (150-154) 2007], we
proposed a classical model for the expansion of the Universe during the
radiation-dominated epoch based on the gravitational repulsion of the
Reissner-Nordstrom geometry - naked singularity description of particles that
"grow" with the drop of the temperature. In this work we model the Universe
during the Reissner-Nordstrom expansion as a van der Waals gas and determine
the equation of state.

32
The categories of this paper are: atom-ph
30
The categories of this paper are: q-alg
35
The categories of this paper are: mtrl-th
8
The categories of this paper are: hep-ex
10
The categories of this paper are: q-bio
16
The categories of this paper are: stat
25
The categories of this paper are: patt-sol
29
The categories of this paper are: funct-an
24
The categories of this paper are: dg-ga
17
The categories of this paper are: q-fin
21
The categories of this paper are: adap-org
19
The categories of this paper are: eess
26
The categories of this paper are: bayes-an
36
The categories of this paper are: cmp-lg
23
The categories of this paper are: solv-int
4
The categories of this paper are: cond-mat