Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Electric Polarization of Heteropolar Nanotubes as a Geometric Phase   The three-fold symmetry of planar boron nitride, the III-V analog to
graphene, prohibits an electric polarization in its ground state, but this
symmetry is broken when the sheet is wrapped to form a BN nanotube. We show
that this leads to an electric polarization along the nanotube axis which is
controlled by the quantum mechanical boundary conditions on its electronic
states around the tube circumference. Thus the macroscopic dipole moment has an
{\it intrinsically nonlocal quantum} mechanical origin from the wrapped
dimension. We formulate this novel phenomenon using the Berry's phase approach
and discuss its experimental consequences.

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The categories of this paper are: physics
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The categories of this paper are: econ
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The categories of this paper are: chem-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: eess
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The categories of this paper are: hep-lat
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The categories of this paper are: funct-an
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The categories of this paper are: math-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: dg-ga
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The categories of this paper are: adap-org
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The categories of this paper are: math
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The categories of this paper are: mtrl-th
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The categories of this paper are: nlin
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The categories of this paper are: bayes-an