Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: An exact model for evaporating primordial black holes in cosmological
  space-time   Primordial black holes (PBHs) in the mass range $10^{17} - 10^{23}~{\rm gm}$
are considered as possible dark matter candidates as they are not subject to
big-bang nucleosynthesis constraints and behave like cold dark matter. If PBHs
are indeed dark matter, they cannot be treated as isolated objects in
asymptotic flat space-time. Furthermore, when compared to stellar-mass black
holes, the rate at which the Hawking particles radiate out from PBHs is
significantly faster. In this work, we obtain an exact time-dependent solution
that models evaporating black holes in the cosmological background. As a
result, the solution considers all three aspects of PBHs -- mass-loss due to
Hawking radiation, black hole surrounded by mass distribution, and cosmological
background. Furthermore, our model predicts that the decay of PBHs occurs
faster for larger masses; however, \emph{the decay rate reduces for lower
mass}. Finally, we discuss the implications of theoretical constraints on PBHs
as dark matter.

37
The categories of this paper are: supr-con
9
The categories of this paper are: nlin
12
The categories of this paper are: nucl-th
16
The categories of this paper are: stat
13
The categories of this paper are: quant-ph
17
The categories of this paper are: q-fin
28
The categories of this paper are: alg-geom
30
The categories of this paper are: q-alg
32
The categories of this paper are: atom-ph
1
The categories of this paper are: cs
14
The categories of this paper are: math-ph
3
The categories of this paper are: physics
15
The categories of this paper are: nucl-ex
20
The categories of this paper are: acc-phys
10
The categories of this paper are: q-bio
18
The categories of this paper are: econ