Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Use of delta N formalism - Difficulties in generating large local-type
  non-Gaussianity during inflation -   We discuss generation of non-Gaussianity in density perturbation through the
super-horizon evolution during inflation by using the so-called $\delta N$
formalism. We first provide a general formula for the non-linearity parameter
generated during inflation. We find that it is proportional to the slow-roll
parameters, multiplied by the model dependent factors that may enhance the
non-gaussianity to the observable ranges. Then we discuss three typical
examples to illustrate how difficult to generate sizable non-Gaussianity
through the super-horizon evolution. First example is the double inflation
model, which shows that temporal violation of slow roll conditions is not
enough for the generation of non-Gaussianity. Second example is the ordinary
hybrid inflation model, which illustrates the importance of taking into account
perturbations on small scales. Finally, we discuss Kadota-Stewart model. This
model gives an example in which we have to choose rather unnatural initial
conditions even if large non-Gaussianity can be generated.

9
The categories of this paper are: nlin
1
The categories of this paper are: cs
24
The categories of this paper are: dg-ga
37
The categories of this paper are: supr-con
3
The categories of this paper are: physics
34
The categories of this paper are: chem-ph
29
The categories of this paper are: funct-an
17
The categories of this paper are: q-fin
28
The categories of this paper are: alg-geom
27
The categories of this paper are: comp-gas
8
The categories of this paper are: hep-ex
26
The categories of this paper are: bayes-an
31
The categories of this paper are: ao-sci
22
The categories of this paper are: chao-dyn
25
The categories of this paper are: patt-sol
19
The categories of this paper are: eess