Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Evolution of quantum field, particle content and classicality in the
  three stage universe   We study the evolution of a quantum scalar field in a toy universe which has
three stages of evolution, viz., (i) an early (inflationary) de Sitter phase
(ii) radiation dominated phase and (iii) late-time (cosmological constant
dominated) de Sitter phase. Using Schr\"odinger picture, the scalar field
equations are solved separately for the three stages and matched at the
transition points. The boundary conditions are chosen so that field modes in
the early de Sitter evolves from Bunch-Davies vacuum state. We determine the
(time-dependent) particle content of this quantum state for the entire
evolution of the universe and describe the various features both numerically
and analytically. We also describe the quantum to classical transition in terms
of a {\it classicality parameter} which tracks the particle creation and its
effect on phase space correlation of the quantum field.

26
The categories of this paper are: bayes-an
0
The categories of this paper are: hep-ph
36
The categories of this paper are: cmp-lg
24
The categories of this paper are: dg-ga
3
The categories of this paper are: physics
12
The categories of this paper are: nucl-th
34
The categories of this paper are: chem-ph
8
The categories of this paper are: hep-ex
2
The categories of this paper are: math
35
The categories of this paper are: mtrl-th
23
The categories of this paper are: solv-int
13
The categories of this paper are: quant-ph
22
The categories of this paper are: chao-dyn
28
The categories of this paper are: alg-geom
29
The categories of this paper are: funct-an
10
The categories of this paper are: q-bio