Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Volkov States and Non-linear Compton Scattering in Short and Intense
  Laser Pulses   The collision of ultra-relativistic electron beams with intense short laser
pulses makes possible to study QED in the high-intensity regime. Present day
high-intensity lasers mostly operate with short pulse durations of several tens
of femtoseconds, i.e. only a few optical cycles. A profound theoretical
understanding of short pulse effects is important not only for studying
fundamental aspects of high-intensity laser matter interaction, but also for
applications as novel X- and gamma-ray radiation sources. In this article we
give a brief overview of the theory of high-intensity QED with focus on effects
due to the short pulse duration. The non-linear spectral broadening in
non-linear Compton scattering due to the short pulse duration and its
compensation is discussed.

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The categories of this paper are: astro-ph
29
The categories of this paper are: funct-an
26
The categories of this paper are: bayes-an
30
The categories of this paper are: q-alg
12
The categories of this paper are: nucl-th
20
The categories of this paper are: acc-phys
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The categories of this paper are: dg-ga
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The categories of this paper are: nlin
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The categories of this paper are: cs
32
The categories of this paper are: atom-ph
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The categories of this paper are: gr-qc
28
The categories of this paper are: alg-geom
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The categories of this paper are: quant-ph
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The categories of this paper are: nucl-ex
22
The categories of this paper are: chao-dyn
4
The categories of this paper are: cond-mat