Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Femtosecond pulses and dynamics of molecular photoexcitation: RbCs
  example   We investigate the dynamics of molecular photoexcitation by unchirped
femtosecond laser pulses using RbCs as a model system. This study is motivated
by a goal of optimizing a two-color scheme of transferring
vibrationally-excited ultracold molecules to their absolute ground state. In
this scheme the molecules are initially produced by photoassociation or
magnetoassociation in bound vibrational levels close to the first dissociation
threshold. We analyze here the first step of the two-color path as a function
of pulse intensity from the low-field to the high-field regime. We use two
different approaches, a global one, the 'Wavepacket' method, and a restricted
one, the 'Level by Level' method where the number of vibrational levels is
limited to a small subset. The comparison between the results of the two
approaches allows one to gain qualitative insights into the complex dynamics of
the high-field regime. In particular, we emphasize the non-trivial and
important role of far-from-resonance levels which are adiabatically excited
through 'vertical' transitions with a large Franck-Condon factor. We also point
out spectacular excitation blockade due to the presence of a quasi-degenerate
level in the lower electronic state. We conclude that selective transfer with
femtosecond pulses is possible in the low-field regime only. Finally, we extend
our single-pulse analysis and examine population transfer induced by coherent
trains of low-intensity femtosecond pulses.

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The categories of this paper are: gr-qc
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The categories of this paper are: eess
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The categories of this paper are: astro-ph
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The categories of this paper are: math-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: dg-ga
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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: hep-lat
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The categories of this paper are: stat
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The categories of this paper are: nlin
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The categories of this paper are: q-alg
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The categories of this paper are: solv-int
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The categories of this paper are: plasm-ph
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The categories of this paper are: math
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The categories of this paper are: hep-th