Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Ab initio investigation of light-induced relativistic spin-flip effects
  in magneto-optics   Excitation of a metallic ferromagnet such as Ni with an intensive femtosecond
laser pulse causes an ultrafast demagnetization within approximately 300 fs. It
was proposed that the ultrafast demagnetization measured in femtosecond
magneto-optical experiments could be due to relativistic light-induced
processes. We perform an ab initio investigation of the influence of
relativistic effects on the magneto-optical response of Ni. To this end, we
develop, first, a response theory formulation of the additional appearing
ultra-relativistic terms in the Foldy-Wouthuysen transformed Dirac Hamiltonian
due to the electromagnetic field, and, second, compute the influence of
relativistic light-induced spin-flip transitions on the magneto-optics. Our ab
initio calculations of relativistic spin-flip optical excitations predict that
these can give only a very small contribution ($\leq 0.1$%) to the
laser-induced magnetization change in Ni.

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The categories of this paper are: nucl-ex
3
The categories of this paper are: physics
0
The categories of this paper are: hep-ph
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The categories of this paper are: econ
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The categories of this paper are: chao-dyn
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The categories of this paper are: funct-an
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The categories of this paper are: q-fin
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The categories of this paper are: stat
28
The categories of this paper are: alg-geom
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The categories of this paper are: acc-phys
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The categories of this paper are: adap-org
33
The categories of this paper are: plasm-ph
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The categories of this paper are: chem-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: astro-ph
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The categories of this paper are: quant-ph