Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Direct Detection of the Primordial Inflationary Gravitational Waves   Inflationary cosmology is successful in explaining a number of outstanding
cosmological issues including the flatness, the horizon and the relic issues.
More spectacular is the experimental confirmation of the structure as arose
from the inflationary quantum fluctuations. However, the physics in the
inflationary era is unclear. Polarization observations of Cosmic Microwave
Background (CMB) missions may detect the tensor mode effects of inflationary
gravitational waves (GWs) and give an energy scale of inflation. To probe the
inflationary physics, direct observation of gravitational waves generated in
the inflationary era is needed. In this essay, we advocate that the direct
observation of these GWs with sensitivity Omega-gw down to 10**(-23) is
possible using present projected technology development if foreground could be
separated.

23
The categories of this paper are: solv-int
25
The categories of this paper are: patt-sol
3
The categories of this paper are: physics
20
The categories of this paper are: acc-phys
4
The categories of this paper are: cond-mat
24
The categories of this paper are: dg-ga
13
The categories of this paper are: quant-ph
12
The categories of this paper are: nucl-th
33
The categories of this paper are: plasm-ph
36
The categories of this paper are: cmp-lg
18
The categories of this paper are: econ
37
The categories of this paper are: supr-con
32
The categories of this paper are: atom-ph
19
The categories of this paper are: eess
8
The categories of this paper are: hep-ex
27
The categories of this paper are: comp-gas