Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Polarization Transfer from the Twisted Light to an Atom   When polarized light is absorbed by an atom, the excited atomic system
carries information about the initial polarization of light. For the light that
carries an orbital angular momentum, or the twisted light, the polarization
states are described by eight independent parameters, as opposed to three
Stokes parameters for plane waves. We use a parameterization of the
spin-density matrix of the twisted light in terms of vector and tensor
polarization, in analogy with massive spin-1 particles, and derive formulae
that define atom's response to specific polarization components of the twisted
light. It is shown that for dipole ($S\to P$) atomic transitions, the atom's
polarization is in one-to-one correspondence with polarization of the incident
light; this relation is violated, however, for the transitions of higher
multipolarity ($S\to D$, $S\to F$, etc.) We pay special attention to
contributions of the longitudinal electric field into the matrix elements of
atomic transitions.

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The categories of this paper are: plasm-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: econ
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The categories of this paper are: cs
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The categories of this paper are: chem-ph
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The categories of this paper are: math
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The categories of this paper are: nucl-ex
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The categories of this paper are: cmp-lg
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The categories of this paper are: hep-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: stat
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The categories of this paper are: astro-ph
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The categories of this paper are: adap-org
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The categories of this paper are: acc-phys
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The categories of this paper are: math-ph
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The categories of this paper are: q-fin