Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Band structure loops and multistability in cavity-QED   We calculate the band structure of ultracold atoms located inside a
laser-driven optical cavity. For parameters where the atom-cavity system
exhibits bistability, the atomic band structure develops loop structures akin
to the ones predicted for Bose-Einstein condensates in ordinary (non-cavity)
optical lattices. However, in our case the nonlinearity derives from the cavity
back-action rather than from direct interatomic interactions. We find both bi-
and tri-stable regimes associated with the lowest band, and show that the
multistability we observe can be analyzed in terms of swallowtail catastrophes.
Dynamic and energetic stability of the mean-field solutions is also discussed,
and we show that the bistable solutions have, as expected, one unstable and two
stable branches. The presence of loops in the atomic band structure has
important implications for proposals concerning Bloch oscillations of atoms
inside optical cavities [Peden et al., Phys. Rev. A 80, 043803 (2009), Prasanna
Venkatesh et al., Phys. Rev. A 80, 063834 (2009)].

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The categories of this paper are: math-ph
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The categories of this paper are: hep-lat
1
The categories of this paper are: cs
20
The categories of this paper are: acc-phys
34
The categories of this paper are: chem-ph
7
The categories of this paper are: hep-th
8
The categories of this paper are: hep-ex
31
The categories of this paper are: ao-sci
21
The categories of this paper are: adap-org
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The categories of this paper are: nucl-th
32
The categories of this paper are: atom-ph
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The categories of this paper are: nucl-ex
9
The categories of this paper are: nlin
27
The categories of this paper are: comp-gas
37
The categories of this paper are: supr-con
6
The categories of this paper are: astro-ph