Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Filtered Talbot lens: Producing $\lambda /2n$-periodic atomic patterns
  with standing wave fields having period $\lambda $   We propose a scheme to create high-contrast, periodic atom density
distributions having period $\lambda /2n$ using the Talbot effect, where $%
\lambda $ is the wave length of the optical fields that scatter the atoms and
$n$ is a positive integer. This {\em filtered Talbot lens} is comprised of two
standing-wave optical fields. An atomic beam propagates perpendicular to the
fields. The first field, which is far-detuned from the atomic transition
frequency, acts as an array of lenses that focuses the atoms. The second field,
positioned at the atom optical focus of the first, is resonant with the atomic
transition frequency and acts as an amplitude mask, leaving unperturbed only
those atoms that pass through its nodes. At distances following the interaction
with the second field that are equal to an integral fraction of the Talbot
length, atomic density gratings having period $\lambda /2n$ are formed.

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The categories of this paper are: cs
9
The categories of this paper are: nlin
37
The categories of this paper are: supr-con
24
The categories of this paper are: dg-ga
10
The categories of this paper are: q-bio
25
The categories of this paper are: patt-sol
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The categories of this paper are: hep-th
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The categories of this paper are: math
34
The categories of this paper are: chem-ph
14
The categories of this paper are: math-ph
31
The categories of this paper are: ao-sci
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The categories of this paper are: hep-ph
33
The categories of this paper are: plasm-ph
26
The categories of this paper are: bayes-an
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The categories of this paper are: nucl-th
35
The categories of this paper are: mtrl-th