Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Amplification of Cosmological Inhomogeneities by the QCD Transition   The cosmological QCD transition affects primordial density perturbations. If
the QCD transition is first order, the sound speed vanishes during the
transition and density perturbations fall freely. For scales below the Hubble
radius at the transition the primordial Harrison-Zel'dovich spectrum of density
fluctuations develops large peaks and dips. These peaks grow with wave number
for both the hadron-photon-lepton fluid and for cold dark matter. At the
horizon scale the enhancement is small. This by itself does not lead to the
formation of black holes at the QCD transition. The peaks in the
hadron-photon-lepton fluid are wiped out during neutrino decoupling. For cold
dark matter that is kinetically decoupled at the QCD transition (e.g., axions
or primordial black holes) these peaks lead to the formation of CDM clumps of
masses $10^{-20} M_\odot< M_{\rm clump} < 10^{-10} M_\odot$.

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The categories of this paper are: bayes-an
15
The categories of this paper are: nucl-ex
8
The categories of this paper are: hep-ex
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The categories of this paper are: dg-ga
18
The categories of this paper are: econ
31
The categories of this paper are: ao-sci
7
The categories of this paper are: hep-th
16
The categories of this paper are: stat
34
The categories of this paper are: chem-ph
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The categories of this paper are: q-fin
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The categories of this paper are: solv-int
2
The categories of this paper are: math
36
The categories of this paper are: cmp-lg
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The categories of this paper are: comp-gas
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The categories of this paper are: acc-phys
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The categories of this paper are: supr-con