Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Inflation and Preheating in NO models   We study inflationary models in which the effective potential of the inflaton
field does not have a minimum, but rather gradually decreases at large $\phi$.
In such models the inflaton field does not oscillate after inflation, and its
effective mass becomes vanishingly small, so the standard theory of reheating
based on the decay of the oscillating inflaton field does not apply. For a long
time the only mechanism of reheating in such non-oscillatory (NO) models was
based on gravitational particle production in an expanding universe. This
mechanism is very inefficient. We will show that it may lead to cosmological
problems associated with large isocurvature fluctuations and overproduction of
dangerous relics such as gravitinos and moduli fields. We also note that the
setting of initial conditions for the stage of reheating in these models should
be reconsidered. All of these problems can be resolved in the context of the
recently proposed scenario of instant preheating if there exists an interaction
${g^2} \phi^2\chi^2$ of the inflaton field $\phi$ with another scalar field
$\chi$. We show that the mechanism of instant preheating in NO models is much
more efficient than the usual mechanism of gravitational particle production
even if the coupling constant $g^2$ is extremely small, $10^{-14} \ll g^2 \ll
1$.

31
The categories of this paper are: ao-sci
18
The categories of this paper are: econ
34
The categories of this paper are: chem-ph
33
The categories of this paper are: plasm-ph
16
The categories of this paper are: stat
20
The categories of this paper are: acc-phys
8
The categories of this paper are: hep-ex
29
The categories of this paper are: funct-an
9
The categories of this paper are: nlin
24
The categories of this paper are: dg-ga
26
The categories of this paper are: bayes-an
3
The categories of this paper are: physics
30
The categories of this paper are: q-alg
21
The categories of this paper are: adap-org
14
The categories of this paper are: math-ph
23
The categories of this paper are: solv-int