Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Nonequilibrium inflaton dynamics and reheating: Back reaction of
  parametric particle creation and curved spacetime effects   We present a detailed and systematic analysis of the nonperturbative,
nonequilibrium dynamics of a quantum field in the reheating phase of
inflatonary cosmology, including full back reactions of the quantum field on
the curved spacetime, as well as the fluctuations on the mean field. We use the
O(N) field theory with unbroken symmetry in a spatially flat FRW universe to
study the dynamics of the inflaton in the post-inflaton, preheating stage.
Oscillations of the inflaton's zero mode induce parametric amplification of
quantum fluctuations, resulting in a rapid transfer of energy to the
inhomogeneous modes of the inflaton field. We adopt the coupled nonperturbative
equations for the mean field and variance derived in a preceding paper
[gr-qc/9706001] by means of a two-particle-irreducible (2PI), closed-time-path
(CTP) effective action for curved spacetime while specialized to leading order
in the 1/N expansion. Adiabatic regularization is employed. The renormalized
dynamical equations are evolved numerically from initial data which are generic
to the end state of slow roll in many inflatonary cosmological scenarios. The
initial conditions consist of a large-amplitude, quasiclassical, oscillating
mean field, and a variance given by the de Sitter-invariant vacuum. We find
that for sufficiently large initial mean-field amplitudes in this model, the
parametric resonance effect alone (in a collisionless approximation) is not an
efficient means to "preheat" the quantum field. For small initial mean-field
amplitude, damping of the mean field via parametric amplification of quantum
fluctuations is seen to occur. Our results indicate that the self-consistent
dynamics of spacetime plays an important role in determining the physics of the
post-inflatonary Universe.

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The categories of this paper are: math-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: math
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The categories of this paper are: bayes-an
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The categories of this paper are: eess
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The categories of this paper are: acc-phys
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The categories of this paper are: supr-con
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The categories of this paper are: hep-th
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The categories of this paper are: q-bio
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The categories of this paper are: chao-dyn
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The categories of this paper are: quant-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: patt-sol
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The categories of this paper are: astro-ph
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The categories of this paper are: econ
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The categories of this paper are: adap-org