Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Emergence of Classical Orbits in Few-Cycle Above-Threshold Ionization   The time-dependent Schr\"odinger equation for atomic hydrogen in few-cycle
laser pulses is solved numerically. Introducing a positive definite quantum
distribution function in energy-position space, a straightforward comparison of
the numerical ab initio results with classical orbit theory is facilitated.
Integration over position space yields directly the photoelectron spectra so
that the various pathways contributing to a certain energy in the photoelectron
spectra can be established in an unprecedented direct and transparent way.

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The categories of this paper are: comp-gas
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The categories of this paper are: eess
32
The categories of this paper are: atom-ph
22
The categories of this paper are: chao-dyn
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The categories of this paper are: solv-int
10
The categories of this paper are: q-bio
0
The categories of this paper are: hep-ph
29
The categories of this paper are: funct-an
8
The categories of this paper are: hep-ex
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The categories of this paper are: ao-sci
9
The categories of this paper are: nlin
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The categories of this paper are: econ
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The categories of this paper are: quant-ph
5
The categories of this paper are: gr-qc
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The categories of this paper are: cmp-lg
33
The categories of this paper are: plasm-ph