Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Berry-phase description of Topological Crystalline Insulators   We study a class of translational-invariant insulators with discrete
rotational symmetry. These insulators have no spin-orbit coupling, and in some
cases have no time-reversal symmetry as well, i.e., the relevant symmetries are
purely crystalline. Nevertheless, topological phases exist which are
distinguished by their robust surface modes. Like many well-known topological
phases, their band topology is unveiled by the crystalline analog of Berry
phases, i.e., parallel transport across certain non-contractible loops in the
Brillouin zone. We also identify certain topological phases without any robust
surface modes -- they are uniquely distinguished by parallel transport along
bent loops, whose shapes are determined by the symmetry group. Our findings
have experimental implications in cold-atom systems, where the crystalline
Berry phase has been directly measured.

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The categories of this paper are: funct-an
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The categories of this paper are: q-bio
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The categories of this paper are: econ
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The categories of this paper are: plasm-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: hep-ex
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The categories of this paper are: cs
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The categories of this paper are: ao-sci
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The categories of this paper are: gr-qc
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The categories of this paper are: nlin
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The categories of this paper are: stat
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The categories of this paper are: adap-org
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The categories of this paper are: math-ph
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The categories of this paper are: eess
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The categories of this paper are: atom-ph
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The categories of this paper are: supr-con