Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Scalar Field Dynamics in Friedman Robertson Walker Spacetimes   We study the non-linear dynamics of quantum fields in matter and radiation
dominated universes, using the non-equilibrium field theory approach combined
with the non-perturbative Hartree and the large N approximations. We examine
the phenomenon of explosive particle production due to spinodal instabilities
and parametric amplification in expanding universes with and without symmetry
breaking. For a variety of initial conditions, we compute the evolution of the
inflaton, its quantum fluctuations, and the equation of state. We find
explosive growth of quantum fluctuations, although particle production is
somewhat sensitive to the expansion of the universe. In the large N limit for
symmetry breaking scenarios, we determine generic late time solutions for any
flat Friedman-Robertson-Walker cosmology. We also present a complete and
numerically implementable renormalization scheme for the equation of motion and
the energy momentum tensor in flat FRW cosmologies. In this scheme the
renormalization constants are independent of time and of the initial
conditions.

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The categories of this paper are: cs
32
The categories of this paper are: atom-ph
7
The categories of this paper are: hep-th
28
The categories of this paper are: alg-geom
23
The categories of this paper are: solv-int
12
The categories of this paper are: nucl-th
37
The categories of this paper are: supr-con
9
The categories of this paper are: nlin
2
The categories of this paper are: math
17
The categories of this paper are: q-fin
13
The categories of this paper are: quant-ph
3
The categories of this paper are: physics
5
The categories of this paper are: gr-qc
27
The categories of this paper are: comp-gas
34
The categories of this paper are: chem-ph
8
The categories of this paper are: hep-ex