Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Trapped Fermi Gases in Rotating Optical Lattices: Realization and
  Detection of the Topological Hofstadter Insulator   We consider a gas of non-interacting spinless fermions in a rotating optical
lattice and calculate the density profile of the gas in an external confinement
potential. The density profile exhibits distinct plateaus, which correspond to
gaps in the single particle spectrum known as the Hofstadter butterfly. The
plateaus result from insulating behavior whenever the Fermi energy lies within
a gap. We discuss the necessary conditions to realize the Hofstadter insulator
in a cold atom setup and show how the quantized Hall conductance can be
measured from density profiles using the St\v{r}eda formula.

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The categories of this paper are: hep-ex
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The categories of this paper are: nucl-th
31
The categories of this paper are: ao-sci
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The categories of this paper are: q-fin
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The categories of this paper are: quant-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: econ
15
The categories of this paper are: nucl-ex
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The categories of this paper are: eess
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The categories of this paper are: hep-th
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The categories of this paper are: q-bio
0
The categories of this paper are: hep-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: dg-ga
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The categories of this paper are: astro-ph
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The categories of this paper are: acc-phys