Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Observing Ultra-High Energy Cosmic Rays with Smartphones   We propose a novel approach for observing cosmic rays at ultra-high energy
($>10^{18}$~eV) by repurposing the existing network of smartphones as a ground
detector array. Extensive air showers generated by cosmic rays produce muons
and high-energy photons, which can be detected by the CMOS sensors of
smartphone cameras. The small size and low efficiency of each sensor is
compensated by the large number of active phones. We show that if user adoption
targets are met, such a network will have significant observing power at the
highest energies.

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The categories of this paper are: alg-geom
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The categories of this paper are: hep-lat
19
The categories of this paper are: eess
37
The categories of this paper are: supr-con
8
The categories of this paper are: hep-ex
32
The categories of this paper are: atom-ph
34
The categories of this paper are: chem-ph
13
The categories of this paper are: quant-ph
5
The categories of this paper are: gr-qc
9
The categories of this paper are: nlin
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The categories of this paper are: solv-int
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The categories of this paper are: patt-sol
4
The categories of this paper are: cond-mat
21
The categories of this paper are: adap-org
7
The categories of this paper are: hep-th
29
The categories of this paper are: funct-an