Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Photoionization of hydrogen atom by coherent intense high-frequency
  short laser pulses: Direct propagation of electron wave packets on large
  spatial grids   The time-dependent Schr\"{o}dinger equation for the hydrogen atom and its
interaction with coherent intense high-frequency short laser pulses is solved
numerically exactly by propagating the single-electron wave packets. Thereby,
the wavefunction is followed in space and time for times longer than the pulse
duration. Results are explicitly shown for 3 and 10 fs pulses. Particular
attention is paid to identifying the effect of dynamic interference of
photoelectrons emitted with the same kinetic energy at different times during
the rising and falling sides of the pulse predicted in [\emph{Ph.V. Demekhin
and L.S. Cederbaum}, Phys. Rev. Lett. \textbf{108}, 253001 (2012)]. In order to
be able to see the dynamic interference pattern in the computed electron
spectra, the photoelectron wave packet has to be propagated over long
distances. Clearly, complex absorption potentials often employed to compute
spectra of emitted particles cannot be used to detect dynamic interference. For
the considered high-frequency pulses of 3 and 10 fs durations, this requires
enormously large spatial grids. The presently computed photoionization and
above-threshold ionization spectra are found to exhibit pronounced dynamic
interference patterns. Where available, the patterns are in very good agreement
with previously published results on the photoionization spectra which have
been computed using a completely different method, thus supporting the
previously made assumption that the above-threshold ionization processes are
very weak for the considered pulse intensities and high carrier frequency. The
quiver motion in space and time of a free electron in strong laser pulses is
also investigated numerically. Finally, a discussion is presented of how fast
the atom is ionized by an intense pulse.

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The categories of this paper are: nlin
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The categories of this paper are: nucl-th
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The categories of this paper are: q-bio
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The categories of this paper are: cond-mat
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The categories of this paper are: supr-con
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The categories of this paper are: solv-int
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The categories of this paper are: dg-ga
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The categories of this paper are: stat
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The categories of this paper are: mtrl-th
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The categories of this paper are: ao-sci
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The categories of this paper are: patt-sol
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The categories of this paper are: cmp-lg
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The categories of this paper are: nucl-ex
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The categories of this paper are: math-ph
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The categories of this paper are: hep-th
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The categories of this paper are: hep-ex