Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Memory Effect in the Photoinduced Femtosecond Rotation of Magnetization
  in the Ferromagnetic Semiconductor GaMnAs   We report a femtosecond response in photoinduced magnetization rotation in
the ferromagnetic semiconductor GaMnAs, which allows for detection of a
four-state magnetic memory at the femtosecond time scale. The temporal profile
of this cooperative magnetization rotation exhibits a discontinuity that
reveals two distinct temporal regimes, marked by the transition from a highly
non-equilibrium, carrier-mediated regime within the first 200 fs, to a thermal,
lattice-heating picosecond regime.

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The categories of this paper are: quant-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: chao-dyn
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The categories of this paper are: hep-lat
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The categories of this paper are: hep-ph
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The categories of this paper are: cs
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The categories of this paper are: hep-th
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The categories of this paper are: plasm-ph
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The categories of this paper are: adap-org
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The categories of this paper are: nlin
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The categories of this paper are: atom-ph
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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: math-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: econ