Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Cooperative spontaneous emission of three identical atoms   We study the influence of the distribution of atoms on the cooperative
spontaneous emission by a simple model of three identical atoms. The effects of
counter rotating terms are included by a unitary transformation method. By
discussing two special cases that the three atoms are arranged as an
equilateral triangle and in a straight line, we find that the superradiance of
the coherent system largely dependent on the homogeneity of the atoms'
distribution. If the atoms distribute symmetrically, the superradiant emission
will be enhanced. Next, we calculate the emission spectra of three identical
atoms under the single-photon state. We find that the distribution of atoms
also has a great impact on the lamb shift and the spectrum. If three atoms are
placed into an equilateral triangle and the same dipole moment is perpendicular
to the plane of the three atoms, the spectrum will degenerate into two peaks
from the three peaks for general case.

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The categories of this paper are: supr-con
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The categories of this paper are: q-fin
11
The categories of this paper are: hep-lat
23
The categories of this paper are: solv-int
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The categories of this paper are: adap-org
6
The categories of this paper are: astro-ph
28
The categories of this paper are: alg-geom
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The categories of this paper are: dg-ga
15
The categories of this paper are: nucl-ex
5
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: nucl-th
30
The categories of this paper are: q-alg
1
The categories of this paper are: cs
33
The categories of this paper are: plasm-ph
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The categories of this paper are: chem-ph