Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Statistics of CMB polarization angles   We study the distribution functions of the CMB polarization angle $\psi$,
focusing on the Planck 2018 CMB maps. We extend the model of Preece & Battye
(2014) of Gaussian correlated $Q$ and $U$ Stokes parameters to allow nonzero
means. When the variances of $Q$ and $U$ are equal and their covariance and
means are zero, the polarization angle is uniformly distributed. Otherwise the
uniform distribution will be modulated by harmonics with $2\psi$ and $4\psi$
phases. These modulations are visible in the Planck 2018 CMB maps. Furthermore,
the mean value of $U$ is peculiar compared to the power spectrum.

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The categories of this paper are: quant-ph
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The categories of this paper are: supr-con
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The categories of this paper are: acc-phys
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The categories of this paper are: nucl-th
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The categories of this paper are: gr-qc
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The categories of this paper are: atom-ph
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The categories of this paper are: hep-th
36
The categories of this paper are: cmp-lg
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The categories of this paper are: patt-sol
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The categories of this paper are: alg-geom
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The categories of this paper are: eess
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The categories of this paper are: dg-ga
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-lat
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The categories of this paper are: mtrl-th
22
The categories of this paper are: chao-dyn