Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Cosmic 21-cm Fluctuations as a Probe of Fundamental Physics   Fluctuations in high-redshift cosmic 21-cm radiation provide a new window for
observing unconventional effects of high-energy physics in the primordial
spectrum of density perturbations. In scenarios for which the initial state
prior to inflation is modified at short distances, or for which deviations from
scale invariance arise during the course of inflation, the cosmic 21-cm power
spectrum can in principle provide more precise measurements of exotic effects
on fundamentally different scales than corresponding observations of cosmic
microwave background anisotropies.

34
The categories of this paper are: chem-ph
2
The categories of this paper are: math
35
The categories of this paper are: mtrl-th
26
The categories of this paper are: bayes-an
22
The categories of this paper are: chao-dyn
10
The categories of this paper are: q-bio
19
The categories of this paper are: eess
27
The categories of this paper are: comp-gas
21
The categories of this paper are: adap-org
8
The categories of this paper are: hep-ex
24
The categories of this paper are: dg-ga
28
The categories of this paper are: alg-geom
14
The categories of this paper are: math-ph
9
The categories of this paper are: nlin
37
The categories of this paper are: supr-con
31
The categories of this paper are: ao-sci